HB2023 - List of Keywords (simulation)

Paper	Title	Other Keywords	Page
TUC1C1	Effect of Three-Dimensional Quadrupole Magnet Model on Beam Dynamics in the FODO Line at the Spallation Neutron Source Beam Test Facility	quadrupole, neutron, permanent-magnet, HOM	65
	T.E. Thompson ORNL RAD, Oak Ridge, Tennessee, USA A.V. Aleksandrov, T.V. Gorlov, K.J. Ruisard, A.P. Shishlo ORNL, Oak Ridge, Tennessee, USA
	Funding: Supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics. Authored by UT- Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The research program at the Spallation Neutron Source (SNS) Beam Test Facility (BTF) focuses on improving accelerator model accuracy. This study explores the effect of two different models of permanent magnet quadrupoles, which comprise a 9.5-cell FODO line in the BTF. The more realistic model includes all higher-order terms, while the simple, in use model, is a perfect quadrupole. Particular attention is paid to high-amplitude particles to understand how the choice of quadrupole model will affect beam halo distributions. In this paper, we compare particle tracking through a FODO line that contains only linear terms - a perfect quadrupole model - to a full 3D model.
	Slides TUC1C1 [1.705 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC1C1
About •	Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 27 October 2023
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TUC1C2	The Impact of High-Dimensional Phase Space Correlations on the Beam Dynamics in a Linear Accelerator	rfq, linac, MEBT, LEBT	68
	A.M. Hoover, A.V. Aleksandrov, S.M. Cousineau, K.J. Ruisard, A.P. Shishlo, A.P. Zhukov ORNL, Oak Ridge, TN, USA
	Hadron beams develop intensity-dependent transverse-longitudinal correlations within radio-frequency quadrupole (RFQ) accelerating structures. These correlations are only visible in six-dimensional phase space and are destroyed by reconstructions from low-dimensional projections. In this work, we estimate the effect of artificial decorrelation on the beam dynamics in the Spallation Neutron Source (SNS) linac and Beam Test Facility (BTF). We show that the evolution of a realistic initial distribution and its decorrelated twin converge during the early acceleration stages; thus, low-dimensional projections are probably sufficient for detailed predictions in high-power linacs.
	Slides TUC1C2 [6.573 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC1C2
About •	Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 13 October 2023
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TUA2I1	Xsuite: An Integrated Beam Physics Simulation Framework	optics, space-charge, radiation, lattice	73
	G. Iadarola, A. Abramov, X. Buffat, R. De Maria, D. Demetriadou, L. Deniau, P.D. Hermes, P. Kicsiny, P.M. Kruyt, A. Latina, S. Łopaciuk, L. Mether, K. Paraschou, T. Pieloni, G. Sterbini, F.F. Van der Veken CERN, Meyrin, Switzerland P. Belanger UBC & TRIUMF, Vancouver, British Columbia, Canada D. Di Croce, M. Seidel, L. van Riesen-Haupt EPFL, Lausanne, Switzerland P.J. Niedermayer GSI, Darmstadt, Germany
	Xsuite is a newly developed modular simulation package combining in a single flexible and modern framework the capabilities of different tools developed at CERN in the past decades, notably Sixtrack, Sixtracklib, COMBI and PyHEADTAIL. The suite is made of a set of python modules (Xobjects, Xparts, Xtrack, Xcoll, Xfields, Xdpes) that can be flexibly combined together and with other accelerator-specific and general-purpose python tools to study complex simulation scenarios. The code allows for symplectic modeling of the particle dynamics, combined with the effect of synchrotron radiation, impedances, feedbacks, space charge, electron cloud, beam-beam, beamstrahlung, electron lenses. For collimation studies, beam-matter interaction is simulated using the K2 scattering model or interfacing Xsuite with the BDSIM/Geant4 library. Tools are available to compute the accelerator optics functions from the tracking model and to generate particle distributions matched to the optics. Different computing platforms are supported, including conventional CPUs, as well as GPUs from different vendors.
	Slides TUA2I1 [4.388 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA2I1
About •	Received ※ 30 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 22 October 2023
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TUA2I2	Community Modeling Tools for High Brightness Beam Physics	space-charge, interface, framework, plasma	81
	C.E. Mitchell, M. Garten, A. Huebl, R. Lehé, J. Qiang, R.T. Sandberg, J.-L. Vay LBNL, Berkeley, California, USA
	Pushing accelerator technology toward operation with higher intensity hadron beams is critical to meet the needs of future colliders, spallation neutron sources, and neutrino sources. To understand the dynamics of such beams requires a community effort with a comprehensive approach to modeling, from the source to the end of the beam lifetime. One needs efficient numerical models with high spatial resolution and particle statistics, insensitivity to numerical noise, and the ability to resolve low-density halo and particle loss. To meet these challenges, LBNL and collaborators have seeded an open ecosystem of codes, the Beam pLasma & Accelerator Simulation Toolkit (BLAST), that can be combined with each other and with machine learning frameworks to enable integrated start-to-end simulation of accelerator beamlines for accelerator design. Examples of BLAST tools include the PIC codes WarpX and ImpactX. These codes feature GPU acceleration and mesh-refinement, and have openPMD standardized data I/O and a Python interface. We describe these tools and the advantages that open community standards provide to inform the modeling and operation of future high-brightness accelerators.
	Slides TUA2I2 [13.597 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA2I2
About •	Received ※ 03 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 01 November 2023
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TUA2C2	Recent Advances in the CERN PS Impedance Model and Instability Simulations	impedance, kicker, proton, synchrotron	86
	S. Joly La Sapienza University of Rome, Rome, Italy G. Iadarola, N. Mounet, B. Salvant, C. Zannini CERN, Meyrin, Switzerland M. Migliorati INFN-Roma1, Rome, Italy
	Transverse instability growth rates in the CERN Proton Synchrotron are studied thanks to the recently updated impedance model of the machine. Using this model, macroparticle tracking simulations were performed with a new method well-suited for the slicing of short wakes, which achieves comparable performance to the originally implemented method while reducing the required number of slices by a factor of 5 to 10. Dedicated beam-based measurement campaigns were carried out to benchmark the impedance model. Until now, the model underestimated instability growth rates at injection energy. Thanks to a recent addition to the impedance model, namely the kicker magnets¿ connecting cables and their external circuits, the simulated instability growth rates are now comparable to the measured ones.
	Slides TUA2C2 [0.736 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA2C2
About •	Received ※ 28 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 21 October 2023
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TUC2C1	Beam Physics Simulation Studies of 70 Mev ISIS Injector Linac	linac, operation, MEBT, DTL	97
	S.A. Ahmadiannamin, H.V. Cavanagh, S.R. Lawrie, A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The ISIS neutron spallation source is a pioneering research infrastructure in the field of high intensity accelerator physics, catering to scientific users. Comprising a 70 MeV injector linac and an 800 MeV Rapid cycling synchrotron with two beam targets, this facility has witnessed significant upgrades in recent years, leading to enhanced transmission efficiency. Further optimization efforts are underway to ensure continuous improvement. This article focuses on beam physics simulation studies conducted on the current ISIS linac, aiming to gain a deeper understanding and analysis of various phenomena observed during routine operations and accelerator physics experimentation. By examining these phenomena, valuable insights can be obtained to inform the future development of high efficiency injector of ISIS-II.
	Slides TUC2C1 [6.467 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC2C1
About •	Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 13 October 2023
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TUC2C2	Evaluating PyORBIT as Unified Simulation Tool for Beam-Dynamics Modeling of the ESS Linac	lattice, DTL, EPICS, space-charge	102
	J.F. Esteban Müller, Y. Levinsen, N. Milas, C.Z. Zlatanov ESS, Lund, Sweden A.P. Shishlo, A.P. Zhukov ORNL, Oak Ridge, Tennessee, USA
	The design of the ESS proton linac was supported by the simulation code TraceWin, a closed-source commercial software for accurate multiparticle simulations. Conversely, the high-level physics applications used for beam commissioning and machine tuning rely on the Open XAL framework and its online model for fast envelope simulations. In this paper, we evaluate PyORBIT for both online modeling of the linac for machine commissioning and tuning as well as for more accurate offline simulations for beam-dynamics studies. We present the modifications done to the code to adapt it to this use case, namely porting the code to Python 3, adding an envelope tracker, and integrating with the EPICS control systems. Finally, we show the results of benchmarking PyORBIT against our current modeling tools.
	Slides TUC2C2 [0.886 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC2C2
About •	Received ※ 08 October 2023 — Revised ※ 09 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 14 October 2023
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TUA3I2	Measurements of Momentum Halo Due to the Reduced RFQ Voltage During the LIPAc Beam Commissioning	rfq, MMI, operation, cryomodule	112
	K. Hirosawa, A. De Franco, K. Hasegawa, K. Kondo, S. Kwon, K. Masuda, A. Mizuno, M. Sugimoto QST Rokkasho, Aomori, Japan F. Bénédetti CEA-DRF-IRFU, France Y. Carin, H. Dzitko, D. Gex, I. Moya, F. Scantamburlo F4E, Germany J.C. Morales Vega Consorcio IFMIF-DONES España, Granada, Spain I. Podadera CIEMAT, Madrid, Spain
	The Linear IFMIF Prototype Accelerator, LIPAc, is being commissioned aiming in particular at validating the RFQ up to 5MeV beam acceleration. Eventually, the nominal beam of 5 MeV-125 mA in 1 ms/1 Hz pulsed mode was achieved in 2019. The beam operation has been resumed since July 2023 after long maintenance including recovery from unexpected problems in the RFQ RF system. This new phase aims at the commissioning of the full configuration except SRF linac, which is replaced by a temporary beam transport line. Focusing on the RFQ behavior, it will be interesting to operate it at higher duty especially for longer pulses. Indeed, a beam simulation study suggested that the beam extracted from the RFQ includes considerable momentum halo when the RFQ voltage reduces by a few percent, with a slight decrease of mean energy. It can be a potential source of quench like the mismatched beam in the cryomodule. This could be studied measuring the energy from the Time-of-Flight among multiple BPMs while monitoring beam loss around the dipole, where momentum halo should be lost. During the upcoming commissioning, we propose to study them by scanning the RFQ voltage.
	Slides TUA3I2 [4.465 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA3I2
About •	Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 29 October 2023
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TUA4I2	1-MW Beam Operation at J-PARC RCS with Minimum Beam Loss	injection, operation, beam-losses, scattering	147
	P.K. Saha, H. Harada, H. Hotchi, K. Okabe, H. Okita, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The 3-GeV RCS of J-PARC now operates at high-intensity to nearly the designed 1 MW beam. The beam loss and the corresponding residual radiation is one of the key limitations against beam intensity ramp up. Recently, by a series of beam studies and feedback from numerical simulations, we have well mitigated the beam loss to a minimum level and also reduced the beam emittances for beam operation to the spallation neutron source as well as to the main ring. The residual beam loss at the designed 1 MW beam power occurs mostly due to the unavoidable foil scattering beam loss during multi-turn injection, while other beam loss sources have been well mitigated to realize a stable and higher availability beam operation at a nearly 1 MW beam power.
	Slides TUA4I2 [2.303 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA4I2
About •	Received ※ 02 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 21 October 2023
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TUC4I1	A Kicker Impedance Reduction Scheme with Diode Stack and Resistor at the RCS in J-PARC	kicker, impedance, emittance, extraction	162
	Y. Shobuda, H. Harada, P.K. Saha, T. Takayanagi, F. Tamura, T. Togashi, Y. Watanabe, K. Yamamoto, M. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	At the 3-GeV Rapid Cycling Synchrotron (RCS) within the Japan Proton Accelerator Research Complex (J-PARC), kicker impedance causes beam instability. A 1-MW beam with a large emittance can be delivered to the Material and Life Science Experimental Facility (MLF) by suppressing beam instabilities without the need for a transverse feedback system¿simply by turning off the sextuple magnets. However, we require other high-intensity and high-quality beams with smaller emittances for the Main Ring (MR). To address this, we proposed a scheme for suppressing the kicker impedance using a diode stack and resistors, which effectively reduces beam instability. Importantly, these devices have a negligible effect on the extracted beam from the RCS.
	Slides TUC4I1 [2.713 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC4I1
About •	Received ※ 26 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 10 October 2023
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TUC4I2	Development of an Impedance Model for the ISIS Synchrotron and Predictions for the Head-Tail Instability	impedance, kicker, synchrotron, coupling	170
	D.W. Posthuma de Boer, B.A. Orton, C.M. Warsop, R.E. Williamson STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	ISIS is a pulsed, spallation neutron and muon source at the Rutherford Appleton Laboratory in the UK. The rapid cycling synchrotron which drives the facility accelerates 3·10¹³ protons-per-pulse from 70 to 800 MeV at 50 Hz, and delivers a mean beam power of 0.2 MW to two target stations. Beam-loss mechanisms must be understood to optimise performance and minimise equipment activation; and to develop mitigation methods for future operations and new accelerators. Substantial beam-losses are driven by a vertical head-tail instability, which has also limited beam intensity. Beam-based impedance measurements suggest the instability is driven by a low-frequency narrowband impedance, but its physical origin remains unknown. More generally, research into the nature of the instability is hindered without a detailed transverse impedance model. This paper presents a survey of vertical impedance estimates for ISIS equipment, using analytical methods, low frequency CST simulations and lab-based coil measurements. The final impedance estimate is then used as an input to a new linearised Vlasov solver, and predicted growth rates compared with previously obtained experimental results.
	Slides TUC4I2 [4.374 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC4I2
About •	Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 31 October 2023
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TUC4C1	Beam Coupling Impedance of the Main Extraction Kickers in the CERN PS	impedance, kicker, coupling, extraction	178
	M. Neroni, M.J. Barnes, A. Lasheen, C. Vollinger CERN, Meyrin, Switzerland A. Mostacci Sapienza University of Rome, Rome, Italy B.K. Popovic ANL, Lemont, Illinois, USA
	In view of the High Luminosity (HL) upgrade of the LHC, the beam intensity must be doubled in the injector chain. To perform reliable beam dynamics simulations, the beam coupling impedance in the injectors, such as the Proton Synchrotron (PS), must be followed closely by including all contributing elements into the impedance model. The existing kicker magnets of the PS had been optimized for large kick strength and short rise/fall times, but not necessarily to minimise beam coupling impedance. Hence, unwanted beam induced voltage can build up in their electrical circuits, with an impact on the beam. The beam coupling impedances of the two main kicker magnets used for the fast extraction from PS, the KFA71 and KFA79, are extensively characterized in this study. In particular, electromagnetic simulation results for the longitudinal and transverse coupling impedance are shown. The critical impedance contributions are identified, and their effect on beam stability is discussed. Moreover, the impact of the cable terminations on the electromagnetic field pattern and possible mitigation techniques are presented, providing a complete impedance evaluation of the entire kicker installation.
	Slides TUC4C1 [2.715 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC4C1
About •	Received ※ 30 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 15 October 2023
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TUC4C2	Mitigating Collimation Impedance and Improving Halo Cleaning with New Optics and Settings Strategy of the HL-LHC Betatron Collimation System	optics, impedance, collimation, experiment	183
	B. Lindström, R. Bruce, X. Buffat, R. De Maria, L. Giacomel, P.D. Hermes, D. Mirarchi, N. Mounet, T.H.B. Persson, S. Redaelli, R. Tomás García, F.F. Van der Veken, A. Wegscheider CERN, Meyrin, Switzerland
	Funding: Work supported by the HL-LHC project With High Luminosity Large Hadron Collider (HL-LHC) beam intensities, there are concerns that the beam losses in the dispersion suppressors around the betatron cleaning insertion might exceed the quench limits. Furthermore, to maximize the beam lifetime it is important to reduce the impedance as much as possible. The collimators constitute one of the main sources of impedance in HL-LHC, given the need to operate with small collimator gaps. To improve this, a new optics was developed which increases the beta function in the collimation area, as well as the single pass dispersion from the primary collimators to the downstream shower absorbers. Other possible improvements from orbit bumps, to further enhance the locally generated dispersion, and from asymmetric collimator settings were also studied. The new solutions were partially tested with 6.8 TeV beams at the LHC in a dedicated machine experiment in 2022. In this paper, the new performance is reviewed and prospects for future operational deployment are discussed.
	Slides TUC4C2 [2.222 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC4C2
About •	Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 28 October 2023
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WEA1C1	Bunch-by-bunch Tune Shift Studies for LHC-type Beams in the CERN SPS	impedance, injection, wakefield, operation	194
	I. Mases Solé, H. Bartosik, K. Paraschou, M. Schenk, C. Zannini CERN, Meyrin, Switzerland
	After the implementation of major upgrades as part of the LHC Injector Upgrade Project (LIU), the Super Proton Synchrotron (SPS) delivers high intensity bunch trains with 25 ns bunch spacing to the Large Hadron Collider (LHC). These beams are exposed to several collective effects in the SPS, such as beam coupling impedance, space charge and electron cloud, leading to relatively large bunch-by-bunch coherent and incoherent tune shifts. Tune correction to the nominal values at injection is crucial to ensure beam stability and good beam transmission. Measurements of the bunch-by-bunch coherent tune shifts have been performed under different beam conditions. In this paper, we present the measurements of the bunch-by-bunch tune shift as function of bunch intensity for trains of 72 bunches. The experimental data are compared to multiparticle tracking simulations (including other beam variants such as 8b4e beam and hybrid beams) using the SPS impedance model.
	Slides WEA1C1 [2.613 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA1C1
About •	Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 09 October 2023
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WEA2I2	Space Charge Induced Resonances and Suppression in J-PARC MR	resonance, optics, space-charge, operation	222
	T. Yasui KEK, Tokai, Ibaraki, Japan
	In the main ring synchrotron (MR) of Japan Proton Accelerator Research Complex (J-PARC), space charge induced resonances are the cause of beam losses. Although we have scanned the tunes to minimize beam losses, it has been difficult to completely avoid high order structure resonances because the MR has only three super-periodicities. In the present settings for the neutrino operation, we identified that the space charge induced resonance 8ny=171 is the main source of beam losses, except for random resonances. We found that this resonance can be suppressed by beam optics modification while maintaining the tune. In this talk, we present the theoretical, simulation, and experimental results showing the advantages of the new beam optics and the reasons for them.
	Slides WEA2I2 [6.189 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2I2
About •	Received ※ 07 November 2023 — Accepted ※ 18 November 2023 — Issued ※ 29 November 2023
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WEA2C1	Tune Optimization for Alleviating Space Charge Effects and Suppressing Beam Instability in the RCS of CSNS	space-charge, resonance, acceleration, ECR	228
	S.Y. Xu, L. Huang, M.Y. Huang, Y. Li, S. Wang IHEP, Beijing, People’s Republic of China
	The design betatron tune of the Rapid Cycling Synchrotron (RCS) of China Spallation Neutron Source (CSNS) is (4.86, 4.80), which allows for incoherent tune shifts to avoid serious systematic betatron resonances. When the operational bare tune was set at the design value, serious beam instability in the horizontal plane and beam loss induced by half-integer resonance in the vertical plane under space charge detuning were observed. The tunes over the whole acceleration process are optimized based on space charge effects and beam instability. In the RCS, manipulating the tune during the beam acceleration process is a challenge due to the quadrupole magnets being powered by resonant circuits. In the RCS of CSNS, a method of waveform compensation for RCS magnets was investigated to accurately manipulate the magnetic field ramping process. The optimized tune pattern was able to well control the beam loss induced by space charge and beam instability. The beam power of CSNS achieved the design value of 100 kW with small uncontrolled beam loss.
	Slides WEA2C1 [4.710 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2C1
About •	Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 23 October 2023
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WEC2C1	Evaluation of Power Deposition in HL-LHC with Crystal-assisted Heavy Ion Collimation	collimation, heavy-ion, operation, betatron	236
	V. Rodin, R. Bruce, R. Cai, M. D’Andrea, L.S. Esposito, A. Lechner, J.B. Potoine, S. Redaelli, J. Schoofs CERN, Meyrin, Switzerland R. Cai EPFL, Lausanne, Switzerland J.B. Potoine IES, Montpellier, France
	The future LHC heavy-ion program, utilizing 208Pb⁸²⁺ beams at up to 7 Z TeV, is anticipated to operate with substantial intensity upgrade. During periods of short beam lifetime, a potential performance limitation may arise from secondary ions produced by electromagnetic dissociation and hadronic fragmentation in the collimators of the betatron cleaning insertion. These off-rigidity fragments risk quenching superconducting magnets when they are lost in the dispersion suppressor. To address this concern, an alternative collimation scheme will be introduced for forthcoming heavy ion runs, employing bent channeling crystals as primary collimators. In this contribution, we detail a thorough study of power deposition levels in superconducting magnets through FLUKA shower simulations in the crystal-based collimation system. The study focuses on the downstream dispersion suppressor regions of the betatron cleaning insertion, where the quench risk is the highest. Based on this work, we quantify the expected quench margin in future runs with 208Pb⁸²⁺ beams, providing crucial insights for the successful execution of the upgraded heavy-ion program at the HL-LHC. Research supported by the HL-LHC project.
	Slides WEC2C1 [3.105 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC2C1
About •	Received ※ 24 November 2023 — Revised ※ 25 November 2023 — Accepted ※ 29 November 2023 — Issued ※ 16 January 2024
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WEA3C1	The Tracking Code RF-Track and Its Application	electron, linac, positron, space-charge	245
	A. Latina CERN, Meyrin, Switzerland
	RF-Track is a CERN-developed particle tracking code that can simulate the generation, acceleration, and tracking of beams of any species through an entire accelerator, both in realistic field maps and conventional elements. RF-Track includes a large set of single-particle and collective effects: space-charge, beam-beam, beam loading in standing and travelling wave structures, short- and long-range wakefield effects, synchrotron radiation emission, multiple Coulomb scattering in materials, and particle lifetime. These effects make it the ideal tool for the simulation of high-intensity machines. RF-Track has been used for the simulation of electron linacs for medical applications, inverse-Compton-scattering sources, positron sources, protons in Linac4, and the cooling channel of a future muon collider. An overview of the code is presented, along with some significant results.
	Slides WEA3C1 [2.696 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA3C1
About •	Received ※ 26 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 12 October 2023
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WEA3C2	Benchmarking of PATH and RF-Track in the Simulation of Linac4	space-charge, linac, DTL, emittance	249
	G. Bellodi, J.-B. Lallement, A. Latina, A.M. Lombardi CERN, Meyrin, Switzerland
	A benchmarking campaign has been initiated to compare PATH and RF-Track in modelling high-intensity, low-energy hadron beams. The development of extra functionalities in RF-Track was required to handle an unbunched beam from the source and to ease the user interface. The Linac4 RFQ and downstream accelerating structures were adopted as test case scenarios. This paper will give an overview of the results obtained so far and plans for future code development.
	Slides WEA3C2 [4.809 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA3C2
About •	Received ※ 27 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 18 October 2023
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WEA3C3	Differential Algebra for Accelerator Optimization with Truncated Green’s Function	space-charge, framework, multipole, operation	254
	C.S. Park Korea University Sejong Campus, Sejong, Republic of Korea
	Accelerator optimization is a critical problem in the design of high-performance particle accelerators. The truncated Green’s function space charge algorithm is a powerful tool for simulating the effects of space charge in accelerators. However, the truncated Green’s function algorithm can be computationally expensive, especially for large accelerators. In this work, we present a new approach to accelerator optimization using differential algebra with the truncated Green’s function space charge algorithm. Our approach uses differential algebra to symbolically represent the equations of the truncated Green’s function algorithm. This allows us to perform efficient symbolic analysis of the equations, which can be used to identify and optimize the accelerator parameters. We demonstrate the effectiveness of our approach by applying it to the optimization of a linear accelerator. We show that our approach can significantly reduce the computational cost of the truncated Green’s function algorithm, while still achieving high accuracy.
	Slides WEA3C3 [0.772 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA3C3
About •	Received ※ 28 September 2023 — Revised ※ 11 October 2023 — Accepted ※ 14 October 2023 — Issued ※ 18 October 2023
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WEC3C3	Simulations and Measurements of Betatron and Off-momentum Cleaning Performance in the Energy Ramp at the LHC	collimation, betatron, injection, optics	279
	N. Triantafyllou, R. Bruce, M. D’Andrea, K.A. Dewhurst, B. Lindström, D. Mirarchi, S. Redaelli, F.F. Van der Veken CERN, Meyrin, Switzerland
	The Large Hadron Collider (LHC) is equipped with a multistage collimation system that protects the machine against unavoidable beam losses at large betatron and energy offsets at all stages of operation. Dedicated validations and an understanding in simulations of the collimation performance are crucial for the energy ramp from 450 GeV to 6.8 TeV because complex changes of optics and orbit take place in this phase. Indeed, the betatron functions are reduced in all experiments for an efficient setup of the collisions at top energy. In this paper, simulations of the betatron and off-momentum cleaning during the energy ramp are presented. A particular focus is given to the off-momentum losses at the start of the ramp. The simulation results are benchmarked against experimental data, demonstrating the accuracy of the newly developed tools used for the simulations.
	Slides WEC3C3 [1.641 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC3C3
About •	Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 19 October 2023
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WEA4I1	Development of Non-Destructive Beam Envelope Measurements Using BPMs for Low Beta Heavy Ion Beams in SRF Cavities	cavity, emittance, quadrupole, heavy-ion	284
	T. Nishi, O. Kamigaito, N. Sakamoto, T. Watanabe, K. Yamada RIKEN Nishina Center, Wako, Japan T. Adachi RIKEN, Saitama, Japan
	Accurate measurement and control of the beam envelope are crucial issues, particularly in high-power accelerator facilities. However, the use of destructive monitors is limited to low-intensity beams. Furthermore, in the case of beam transport between superconducting cavities, these destructive monitors are avoided to prevent the generation of dust particles and outgassing. In the Superconducting RIKEN LINAC, or SRILAC [1], we utilize 8 non-destructive Beam Energy Position Monitors (BEPMs)[2] to measure beam positions and energies. Recently we are developing a method for estimating the beam envelope by combining the quadrupole moments from BEPMs, which consist of four cosine-shape electrodes, with transfer matrix[3]. While this method has been applied to electron and proton beams, it has not been practically demonstrated for heavy ion beams in beta ¿0.1 regions. By combining BEPM simulations, we are making progress toward the reproduction of experimental results, overcoming specific issues associated with low beta. This development will present the possibility of a new method for beam envelope measurement in LEBT and MEBT, especially for hadron beam facilities. [1] K. Yamada et al., in Proc. SRF2021, paper MOOFAV01(2021). [2] T. Watanabe et al., in Proc. IBIC2020, paper FRAO04 (2020). [3] R. H. Miller et al., in Proc. HEAC¿83, pp. 603¿605 (1983).
	Slides WEA4I1 [10.867 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA4I1
About •	Received ※ 12 October 2023 — Revised ※ 13 October 2023 — Accepted ※ 18 October 2023 — Issued ※ 01 November 2023
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WEA4I2	Linac4 Source and Low Energy Experience and Challenges	rfq, emittance, linac, solenoid	290
	E. Sargsyan, G. Bellodi, F.D.L. Di Lorenzo, J. Etxebarria, J.-B. Lallement, A.M. Lombardi, M. O’Neil CERN, Meyrin, Switzerland
	At the end of Long Shutdown 2 (LS2), in 2020 Linac4 became the new injector of CERN’s proton accelerator complex. The previous version of the Linac4 H⁻ ion source (IS03), produced an operational pulsed peak beam current of 35 mA, resulting in 27 mA after the Radio-Frequency Quadrupole (RFQ). This limited transmission was mainly due to the extracted beam emittance exceeding the acceptance of the RFQ. A new geometry of the Linac4 source extraction electrodes has been developed with the aim of decreasing the extracted beam emittance and increasing the transmission through the RFQ. The new source (IS04) has been studied and thoroughly tested at the Linac4 source test stand. At the start of the 2023 run, the IS04 was installed as operational source in the Linac4 tunnel and is being successfully used for operation with 27 mA peak current after the RFQ. During high-intensity tests, the source, the linac, and the transfer-line to the Proton Synchrotron Booster (PSB) were also tested with a peak beam current of up to 50 mA from the source resulting in 35 mA at the PSB injection. This paper discusses the recent developments, tests, and future plans for the Linac4 H⁻ ion source.
	Slides WEA4I2 [2.217 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA4I2
About •	Received ※ 27 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 29 October 2023
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WEA4C2	Beam Loss Simulations for the Proposed TATTOOS Beamline at HIPA	target, proton, cyclotron, septum	300
	M. Hartmann, D.C. Kiselev, D. Reggiani, M. Seidel, J. Snuverink, H. Zhang PSI, Villigen PSI, Switzerland M. Seidel EPFL, Lausanne, Switzerland
	IMPACT (Isotope and Muon Production with Advanced Cyclotron and Target Technology) is a proposed upgrade project for the high-intensity proton accelerator facility (HIPA) at the Paul Scherrer Institute (PSI). As part of IMPACT, a new radioisotope target station, TATTOOS (Targeted Alpha Tumour Therapy and Other Oncological Solutions) will allow to produce promising radionuclides for diagnosis and therapy of cancer in doses sufficient for clinical studies. The proposed TATTOOS beamline and target will be located near the UCN (Ultra Cold Neutron source) target area, branching off from the main UCN beamline. In particular, the 590 MeV proton beamline is intended to operate at a beam intensity of 100 uA (60 kW), requiring a continuous splitting of the main beam via an electrostatic splitter. Beam loss simulations to verify safe operation have been performed and optimised using BDSIM, a Geant4 based tool enabling the simulation of beam transportation through magnets and particle passage through accelerator. In this study, beam profiles, beam transmission and power deposits are generated and studied. Finally, a quantitative description of the beam halo is introduced.
	Slides WEA4C2 [4.534 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA4C2
About •	Received ※ 29 September 2023 — Revised ※ 04 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 28 October 2023
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WEC4C2	Multiharmonic Buncher for the Isolde Superconducting Recoil Separator Project	ISOL, bunching, cavity, linac	321
	J.L. Muñoz, I. Bustinduy, P.J. González, A. Kaftoosian, L.C. Medina, S. Varnasseri ESS Bilbao, Zamudio, Spain I. Martel University of Huelva, Huelva, Spain
	Funding: This work has been supported by the European Union ¿NextGenerationEU program The ISOLDE Superconducting Recoil Separator (ISRS) is a proposal of building a very compact separator ring as an instrument in the HIE-ISOLDE facility. The injection of the HIE-ISOLDE beam into this ring requires a more compact bunch structure, so a Multi-Harmonic Buncher device is proposed for this task. The MHB will operate at a frequency of 10.128 MHz, which is a 10% of the linac frequency, and would be installed before the RFQ. The MHB is desgined as a two electrodes system, and the MHB signal, composed for the first four harmonics of the fundamental frequency, is fed into the electrodes that are connected to the central conductor of a coaxial waveguides. The full design of the MHB is presented, including electromagnetic optimization of the electrode shape, optimization of the weights of each of the harmonic contribution, mechanical and thermal design of the structure. The RF generation and electronics to power up the device are also presented. A solution that generates directly the composed signal andis then amplified by a solid state power amplifier is also presented in this contribution.
	Slides WEC4C2 [4.165 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC4C2
About •	Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 27 October 2023
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THA1I1	Performance and Upgrade Considerations for the CSNS Injection	injection, MMI, neutron, proton	326
	M.Y. Huang, S. Wang, S.Y. Xu IHEP, Beijing, People’s Republic of China
	Funding: This work is jointly supported by the National Natural Science Foundation of China (Nos. 12075134) and the Guangdong Basic and Applied Basic Research Foundation (No. 2021B1515120021). For the proton synchrotron, the beam injection is one of the most important issues. Firstly, based on the China Spallation Neutron Source (CSNS), the injection methods have been comprehensively studied, including phase space painting and H⁻ stripping. In order to solve the key difficulties faced when the beam power exceeds 50% of the design value, flexibility in the CSNS design has been exploited to implement the correlated painting by using the rising current curve of the pulse power supply. The effectiveness of the new method has been verified in the simulation and beam commissioning. By using the new method, the beam power on the target has successfully risen to the design value. Secondly, for the CSNS upgrade, the injection energy is increased from 80 MeV to 300 MeV and the injection beam power is increased by about 19 times. Based on the CSNS experience and simulation results, it is hoped that the new injection scheme can not only be compatible with correlated and anti-correlated painting, but also greatly reduces the peak temperature of the stripping foil. After in-depth study, a new painting scheme has been proposed which has been verified to be feasible in the simulation.
	Slides THA1I1 [2.951 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THA1I1
About •	Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 15 October 2023
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THA1I2	High-Intensity Studies on the ISIS RCS and Their Impact on the Design of ISIS-II	space-charge, operation, controls, impedance	331
	R.E. Williamson, D.J. Adams, H.V. Cavanagh, B.S. Kyle, D.W. Posthuma de Boer, H. Rafique, C.M. Warsop STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	ISIS is the pulsed spallation neutron and muon source at the Rutherford Appleton Laboratory in the UK. Operation centres on a rapid cycling proton synchrotron (RCS) that accelerates 3·10¹³ protons per pulse from 70 MeV to 800 MeV at 50 Hz, delivering a mean beam power of 0.2 MW. As a high-intensity machine, research at ISIS is predominantly focused on understanding, minimising and controlling beam-loss, which is central to sustainable machine operation. Knowledge of beam-loss mechanisms then informs the design of future high power accelerators such as ISIS-II. This paper provides an overview of the R&D studies currently underway on the ISIS RCS and how these relate to ongoing work understanding and optimising designs for ISIS-II. In particular, recent extensive investigations into observed head-tail instabilities are summarised.
	Slides THA1I2 [10.825 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THA1I2
About •	Received ※ 01 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 18 October 2023
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THA2C1	Measurement of Transverse Beam Emittance for a High-Intensity Proton Injector	solenoid, space-charge, emittance, beam-transport	363
	D.-H. Kim, H.S. Kim, H.-J. Kwon, S. Lee KOMAC, KAERI, Gyeongju, Republic of Korea
	Funding: This work was supported through "KOMAC operation fund" of KAERI by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (KAERI-524320-23) We propose a simple and fast diagnostics method for the transverse beam emittance using a solenoid magnet. The solenoid scan data is analyzed employing the hard edge solenoid model and thick lens approximation. The analytical method is validated by beam dynamics simulations with varying input beam parameters. To address the space charge effect in a simplified manner, the space charge force is linearized and incorporated between segments of the drift-solenoid transfer matrix. For intense hadron injectors with higher beam current accounting for space charge prove to be more effective for correction. Building upon the method validated through beam simulation, experiments are conducted on space charge compensation at the beam test stand in the Korea Multipurpose Accelerator Complex (KOMAC). In a constant ion source operating condition, beam emittance is measured from solenoid scans while varying the flow rate of krypton gas injection. Notable shifts are observed in transverse beam emittance attributable to krypton gas injection, implying some optimal gas flow rate for mitigating emittance growth.
	Slides THA2C1 [3.438 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THA2C1
About •	Received ※ 23 October 2023 — Revised ※ 28 October 2023 — Accepted ※ 30 October 2023 — Issued ※ 20 November 2023
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THA2C2	Comparison of Longitudinal Emittance of Various RFQs	rfq, emittance, focusing, linac	368
	M. Comunian, L. Bellan, A. Pisent INFN/LNL, Legnaro (PD), Italy
	In various projects a large variety of RFQs has been developed, for different application, with different average current, frequency, and energy range. On this article a comparison, in a scaled way, will be done, using the build RFQs of IFMIF, ESS, SPES, ANTHEM, PIAVE. On particular the beam dynamics characteristics will be analyzed, like transmission, output longitudinal emittance and real performance versus simulation.
	Slides THA2C2 [6.261 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THA2C2
About •	Received ※ 30 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 16 October 2023
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THC2I2	Extraction of LHC Beam Parameters from Schottky Signals	synchrotron, betatron, diagnostics, octupole	382
	K. Łasocha, D. Alves, C. Lannoy, N. Mounet CERN, Meyrin, Switzerland C. Lannoy, T. Pieloni EPFL, Lausanne, Switzerland
	Analysis of Schottky signals provides rich insights into the dynamics of a hadron beam, with well-established methods of deriving the betatron tune and machine chromaticity. In this contribution, we will report on recent developments in the analysis and understanding of the signals measured at the Large Hadron Collider during proton and Pb⁸²⁺ fills. A fitting-based technique, where the measured spectra are iteratively compared with theoretical predictions, will be presented and compared with the previous methods. As a step beyond the classical theory of Schottky spectra, certain signal modifications due to the activity of the LHC machine systems will be discussed from the perspective of the applicability of the modified signal to the beam diagnostics.
	Slides THC2I2 [9.053 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THC2I2
About •	Received ※ 04 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 12 October 2023
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THC2C1	Shower Simulations for the CERN Proton Synchrotron Internal Dump and Comparison with Beam Loss Monitor Data	proton, flattop, closed-orbit, operation	389
	S. Niang, L.S. Esposito, M. Giovannozzi, C. Hernalsteens, A. Huschauer, T. Pugnat CERN, Meyrin, Switzerland D. Domange ULB, Bruxelles, Belgium
	During the Long Shutdown 2 (LS2), two new internal dumps (TDIs) were installed and successfully put into operation in the CERN Proton Synchrotron (PS) to withstand the intense and bright beams produced for the High Luminosity LHC. TDIs serve as safety devices designed to rapidly enter the beam trajectory and stop the beam over multiple turns. Due to their design, the TDI only absorbs a fraction of the secondary particle shower produced by beam particles that impinge on it. Starting from impacts computed by multi-turn beam dynamics simulations, detailed shower simulations were performed with FLUKA to assess the radiation field’s impact on the downstream equipment, with a particular emphasis on the dose measured by Beam Loss Monitors. The numerical data obtained from the simulations are compared with the experimental data collected during PS operation.
	Slides THC2C1 [2.092 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THC2C1
About •	Received ※ 28 September 2023 — Revised ※ 09 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 29 October 2023
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THAFP01	Probing Transverse Impedances in the High Frequency Range at the CERN SPS	impedance, betatron, optics, coupling	393
	E. de la Fuente, H. Bartosik, I. Mases Solé, G. Rumolo, C. Zannini CERN, Meyrin, Switzerland
	Funding: CERN The SPS transverse impedance model, which includes the major impedance contributions in the machine, can be benchmarked through measurements of the Head-Tail mode zero instability. Since the SPS works above transition energy, the head tail mode zero is unstable for negative values of chromaticity. The measured instability growth rate is proportional to the real part of the transverse impedance. Studies performed after the LHC Injectors Upgrade (LIU) showed a relevant impedance around 2 GHz with high-gamma transition optics (Q26). This paper presents the follow-up studies to probe the behavior of this beam coupling impedance contribution.
	Slides THAFP01 [2.262 MB]
	Poster THAFP01 [1.149 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP01
About •	Received ※ 29 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 10 October 2023
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THAFP05	A Wireless Method for Beam Coupling Impedance Measurements of the LHC Goniometer	impedance, cavity, coupling, scattering	407
	C. Antuono, C. Zannini CERN, Meyrin, Switzerland M. Migliorati, A. Mostacci LNF-INFN, Frascati, Italy
	The beam coupling impedance (BCI) of an accelerator component should be ideally evaluated exciting the device with the beam itself. However, this scenario is not always attainable and alternative methods must be exploited, such as the bench measurements techniques. The stretched Wire Method (WM) is a well established technique for BCI evaluations, although nowadays its limitations are well known. In particular, the stretched wire perturbs the electromagnetic boundary conditions. Therefore, the results obtained could be inaccurate, especially below the cut-off frequency of the beam pipe in the case of cavity-like structures. To overcome these limitations, efforts are being made to investigate alternative bench measurement techniques that will not require the modification of the device under test (DUT). In this framework, a wireless method has been identified and tested for a pillbox cavity. Its potential for more complex structures, such as the LHC crystal goniometer is explored.
	Slides THAFP05 [1.088 MB]
	Poster THAFP05 [1.151 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP05
About •	Received ※ 29 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 11 October 2023
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THAFP06	Beam Dynamics Study of a 400 kW D⁺ Linear Accelerator to Generate Fusion-Like Neutrons for Breeding Blanket Tests in Korea	linac, target, SRF, MEBT	411
	Y.L. Cheon, M.Y. Ahn, S. Cho, H.W. Kim KFE, Daejeon, Republic of Korea M. Chung, E. Cosgun, D. Kwak, S.H. Moon UNIST, Ulsan, Republic of Korea
	Recently, a pre-conceptual design study was conducted in Korea for developing a dedicated linear accelerator (linac) for 400 kW (40 MeV, maximum 10 mA CW) deuteron (D⁺) beams to generate fusion-like neutrons. The accelerated beam hits a solid Beryllium target to produce fusion-like neutrons, which will be utilized for technical feasibility tests of the breeding blanket including tritium production and recovery. In this work, we present a detailed start-to-end simulation and machine imperfection studies with proper beam tuning, to access the target beam availability and validate the machine specifications. We have designed the 2.45 GHz ECR ion source and a 4-vane type 176 MHz RFQ by using IBSimu, Parmteq, and Toutatis simulation codes. We propose a super-conducting linac with HWR cavities and solenoid focusing magnets to accelerate the beam up to 40 MeV. In the HEBT line, we adopt two octupole magnets and subsequent quadrupoles to make a rectangular-shaped and uniform-density beam with 20 cm x 20 cm footprint at the target. Extensive beam dynamics studies along the linac have been performed using the Tracewin simulation code. Y-L. Cheon et al., Journal of the Korean Physical Society (2023): 1-14. ** S-H. Hong et al., Fusion Engineering and Design 189 (2023): 113449.
	Slides THAFP06 [1.039 MB]
	Poster THAFP06 [1.491 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP06
About •	Received ※ 26 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 21 October 2023
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THAFP09	Optimizing Beam Dynamics in LHC with Active Deep Learning	framework, network, dynamic-aperture, hadron	422
	D. Di Croce, T. Pieloni, M. Seidel EPFL, Lausanne, Switzerland M. Giovannozzi, F.F. Van der Veken CERN, Meyrin, Switzerland E. Krymova SDSC, Lausanne, Switzerland M. Seidel PSI, Villigen PSI, Switzerland
	The Dynamic Aperture (DA) is an important concept for the study of non-linear beam dynamics in a circular accelerator. It refers to the region in phase space where a particle’s motion remains bounded over a given number of turns. Understanding the features of DA is crucial for operating circular accelerators as it provides insights on non-linear beam dynamics and the phenomena affecting beam lifetime. The standard approach to calculate the DA is computationally very intensive. In our study, we aim at determining an optimal set of parameters that affect DA, like betatron tune, chromaticity, and Landau octupole strengths, using a Deep Neural Network (DNN) model. The DNN model predicts the so-called angular DA, based on simulated LHC data. To enhance its performance, we integrated the DNN model into an innovative Active Learning (AL) framework. This framework not only enables retraining and updating of the model, but also facilitates efficient data generation through smart sampling. The results demonstrate that the use of the Active Learning (AL) framework allows faster scanning of LHC ring configuration parameters without compromising the accuracy of the DA calculations.
	Slides THAFP09 [1.028 MB]
	Poster THAFP09 [6.173 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP09
About •	Received ※ 01 October 2023 — Revised ※ 04 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 31 October 2023
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THBP03	ESS-Bilbao RFQ Static Tuning Algorithm and Simulation	rfq, cavity, operation, neutron	440
	J.L. Muñoz, I. Bustinduy, A. Conde, N. Garmendia, P.J. González, J. Martin, V. Toyos ESS Bilbao, Zamudio, Spain
	The ESS-Bilbao RFQ operates at 352.2 MHz. The machining of the four RFQ segments has finished and the assembly and tuning operations will follow shorly. The static tuning and field flatness are provided by an array of 60 plunger tuners, distributed along the 3.2 meters length of the structure. There are four tuners per segment per quadrant, except for one of the segments where the ports are used by the power couplers. A bead-pull setup will provide the measurements of the field profiles, that will be collected in a matrix built up with the contributions of individual tuners. The conventional approach of inverting the matrix to get the optimum tuners distribution is explored, as well as additional optimization method. Particularly, a genetic optimization algorithm provides a very succesful tuning of the RFQ. The solution provided by this approach will be used as the initial configuration of the tuners before the bead-pull measurements are carried out. Additionally, static and dynamic tuning of the RFQ is studied by high performance computing simulations of the RFQ. The analysis of the in-house computational electromagnetics suite used for these tasks is also discussed in this paper.
	Poster THBP03 [2.285 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP03
About •	Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 28 October 2023
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THBP06	RFQ Upgrades for IFMIF-DONES	rfq, emittance, neutron, toolkit	451
	M. Comunian, L. Bellan, A. Palmieri, A. Pisent INFN/LNL, Legnaro (PD), Italy
	In the framework of IFMIF-DONES (International Fusion Materials Irradiation Facility- DEMO-Oriented Neutron Early Source) ¿ a powerful neutron irradiation facility for studies and certification of materials to be used in fusion reactors is planned as part of the European roadmap to fusion electricity. A possible RFQ upgrade has been designed. In this article the beam dynamics of an RFQ able to handle CW 200 mA of Deuterium, based on experience of IFMIF RFQ, will be presented.
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP06
About •	Received ※ 24 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 15 October 2023
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THBP10	A Linearized Vlasov Method for the Study of Transverse e-Cloud Instabilities	electron, quadrupole, dipole, betatron	462
	S. Johannesson, M. Seidel EPFL, Lausanne, Switzerland G. Iadarola CERN, Meyrin, Switzerland
	Using a Vlasov approach, electron cloud driven instabilities can be modeled to study beam stability on time scales that conventional Particle In Cell simulation methods cannot access. The Vlasov approach uses a linear description of electron cloud forces that accounts for both the betatron tune modulation along the bunch and the dipolar kicks from the electron cloud. Forces from electron clouds formed in quadrupole magnets as well as dipole magnets have been expressed in this formalism. In addition, the Vlasov approach can take into account the effect of chromaticity. To benchmark the Vlasov approach, it was compared with macroparticle simulations using the same linear description of electron cloud forces. The results showed good agreement between the Vlasov approach and macroparticle simulations for strong electron clouds, with both approaches showing a stabilizing effect from positive chromaticity. This stabilizing effect is consistent with observations from the LHC.
	Poster THBP10 [4.059 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP10
About •	Received ※ 26 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 14 October 2023
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THBP12	Slow vs Fast Landau Damping Threshold Measurement at the LHC and Implications for the HL-LHC	octupole, damping, experiment, emittance	470
	X. Buffat, L. Giacomel, N. Mounet CERN, Meyrin, Switzerland
	The mechanism of Loss of Landau Damping by Diffusion (L2D2) was observed in dedicated experiments at the LHC using a controlled external source of noise. Nevertheless, the predictions of stability threshold by L2D2 models are plagued by the poor knowledge of the natural noise floor affecting the LHC beams. Experimental measurements of the stability threshold on slow and fast time scales are used to better constrain the model. The improved model is then used to quantify requirements in terms of Landau damping for the HL-LHC.
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP12
About •	Received ※ 29 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 30 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP13	Recent Developments with the New Tools for Collimation Simulations in Xsuite	collimation, coupling, scattering, proton	474
	F.F. Van der Veken, A. Abramov, G. Broggi, F. Cerutti, M. D’Andrea, D. Demetriadou, L.S. Esposito, G. Hugo, G. Iadarola, B. Lindström, S. Redaelli, V. Rodin, N. Triantafyllou CERN, Meyrin, Switzerland
	Simulations of single-particle tracking involving collimation systems need dedicated tools to perform the different tasks needed. These include the accurate description of particle-matter interactions when a tracked particle impacts a collimator jaw; a detailed aperture model to identify the longitudinal location of losses; and others. One such tool is the K2 code in SixTrack, which describes the scattering of high-energy protons in matter. This code has recently been ported into the Xsuite tracking code that is being developed at CERN. Another approach is to couple the tracking with existing tools, such as FLUKA or Geant4, that offer better descriptions of particle-matter interactions and can treat lepton and ion beams. This includes the generation of secondary particles and fragmentation when tracking ions. In addition to the development of coupling with Geant4, the SixTrack-FLUKA coupling has recently been translated and integrated into the Xsuite environment as well. In this paper, we present the ongoing development of these tools. A thorough testing of the new implementation was performed, using as case studies various collimation layout configurations for the LHC Run 3.
	Poster THBP13 [2.785 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP13
About •	Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 13 October 2023 — Issued ※ 23 October 2023
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THBP16	Emittance Growth From Electron Clouds Forming in the LHC Arc Quadrupoles	emittance, resonance, optics, electron	487
	K. Paraschou, H. Bartosik, L. Deniau, G. Iadarola, E.H. Maclean, L. Mether, Y. Papaphilippou, G. Rumolo, R. Tomás García CERN, Meyrin, Switzerland T. Pieloni, J.M.B. Potdevin EPFL, Lausanne, Switzerland
	Operation of the Large Hadron Collider with proton bunches spaced 25 ns apart favours the formation of electron clouds. In fact, a slow emittance growth is observed in proton bunches at injection energy (450 GeV), showing a bunch-by-bunch signature that is compatible with electron cloud effects. The study of these effects is particularly relevant in view of the planned HL-LHC upgrade, which relies on significantly increased beam intensity and brightness. Particle tracking simulations that take into account both electron cloud effects and the non-linear magnetic fields of the lattice suggest that the electron clouds forming in the arc quadrupoles are responsible for the observed degradation. In this work, the simulation results are studied to gain insight into the mechanism which drives the slow emittance growth. Finally, it is discussed how optimising the optics of the lattice can allow the mitigation of such effects.
	Poster THBP16 [3.432 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP16
About •	Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 11 October 2023
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THBP17	Transverse Coherent Instability Studies for the High-Energy Part of the Muon Collider Complex	collider, impedance, cavity, synchrotron	491
	D. Amorim, F. Batsch, L. Bottura, D. Calzolari, C. Carli, H. Damerau, A. Grudiev, A. Lechner, E. Métral, D. Schulte, K. Skoufaris CERN, Geneva, Switzerland A. Chancé CEA-DRF-IRFU, France T. Pieloni EPFL, Lausanne, Switzerland
	Funding: This project has received funding from the European Union¿s Research and Innovation programme under GA No 101094300 and the Swiss Accelerator Research and Technology (CHART) program (www.chart.ch). The International Muon Collider Collaboration (IMCC) is studying a 3 TeV center-of-mass muon collider ring, as well as a possible next stage at 10 TeV. Muons being 200 times heavier than electrons, limitations from synchrotron radiation are mostly suppressed, but the muon decay drives the accelerator chain design. After the muon and anti-muon bunches are produced and 6D cooled, a series of Linac, recirculating Linac and Rapid Cycling Synchrotron (RCS) quickly accelerate the bunches before the collider ring. A large number of RF cavities are required in the RCS to ensure that over 90% of the muons survive in each ring. The effects of cavities higher-order modes on transverse coherent stability have been looked at in detail, including the one of a bunch offset in the cavities, along with possible mitigation measures. In the collider ring, the decay of high-energy muons is a challenge for heat load management and radiation shielding. A tungsten liner would protect the superconducting magnet from decay products. Impedance and related beam stability have been investigated to identify the minimum vacuum chamber radius and transverse damper properties required for stable beams.
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP17
About •	Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 01 November 2023
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THBP29	Effects of Cavity Pre-Detuning on RF Power Transients at Injection into the LHC	cavity, injection, operation, controls	530
	B.E. Karlsen-Bæck, T. Argyropoulos, A.C. Butterworth, R. Calaga, I. Karpov, H. Timko, M. Zampetakis CERN, Meyrin, Switzerland
	At injection into the LHC, the RF system is perturbed by beam-induced voltage resulting in strong RF power transients and the instant detuning of the cavities. The automatic tuning system, however, needs time for the mechanical compensation of the resonance frequency to take place. Acting back on the beam, the transients in RF power are expected to limit the maximum injected intensity by generating unacceptable beam loss. Reducing them is therefore essential to reach the target intensity during the High Luminosity (HL) LHC era. At LHC flat bottom, the cavities are operated using the half-detuning beam-loading compensation scheme. As implemented today, the tuner control algorithm starts acting only after the injection of the first longer bunch train which causes the bunches for this injection to experience the largest power spikes. This contribution presents an adapted detuning scheme for the RF cavities before injection. It was proposed as a path to decrease the transients, hence increasing the available intensity margin for the available RF power. The expected gain is evaluated in particle tracking simulations and measurements acquired during operation.
	Poster THBP29 [3.711 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP29
About •	Received ※ 30 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 22 October 2023
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THBP31	Electron Cloud Effects in the CERN Accelerators in Run 3	electron, operation, injection, kicker	538
	L. Mether, H. Bartosik, L. Giacomel, G. Iadarola, S. Johannesson, I. Mases Solé, K. Paraschou, G. Rumolo, L. Sabato, C. Zannini, E. de la Fuente CERN, Meyrin, Switzerland S. Johannesson EPFL, Lausanne, Switzerland
	Several of the machines in the CERN accelerator complex, in particular the Large Hadron Collider (LHC) and the Super Proton Synchrotron (SPS), are prone to the build-up of electron clouds. Electron cloud effects are observed especially when the machines are operated with a 25 ns bunch spacing, which has routinely been used in the LHC since the start of its second operational run in 2015. After the completion of the LHC Injectors Upgrade program during the latest long shutdown period, the machines are currently operated with unprecedented bunch intensity and beam brightness. With the increase in bunch intensity, electron cloud effects have become one of the main performance limitations, as predicted by simulation studies. In this contribution we present the experimental observations of electron cloud effects since 2021 and discuss their implications for the future operation of the complex.
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP31
About •	Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 23 October 2023
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THBP32	Xobjects and Xdeps: Low-Level Libraries Empowering Beam Dynamics Simulations	GPU, target, interface, lattice	543
	S. Łopaciuk, R. De Maria, G. Iadarola CERN, Meyrin, Switzerland
	Xobjects and Xdeps are Python libraries included in the Xsuite beam dynamics simulation software package. These libraries are crucial to achieving two of the main goals of Xsuite: speed and ease of use. Xobjects allows users to run simulations on various hardware in a platform-agnostic way: with little user intervention single- and multi-threading is supported as well as GPU computations using both CUDA and OpenCL. Xdeps provides support for deferred expressions in Xsuite. Relations among simulation parameters and functions driving properties of lattice elements can be defined or indeed imported from other tools such as MAD-X and then easily updated before or during the simulation.
	Poster THBP32 [0.266 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP32
About •	Received ※ 21 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 17 October 2023
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THBP34	PSI Injector II and the 72 MeV Transfer Line: MinT-Simulation vs. Measurements	cyclotron, emittance, space-charge, extraction	547
	C. Baumgarten, H. Zhang PSI, Villigen PSI, Switzerland
	PSI’s Injector II cyclotron is the only cyclotron worldwide that makes use of the so-called "Vortex effect", in which strong space charge forces generate the counter-intuitive effect to "roll up" bunches thus keeping them longitudinally compact. The effect has been verified by bunch shape measurements and the PIC-code OPAL. However, PSI’s new fast matrix code MinT allows to reproduce the Vortex effect by a linear matrix model which is computational much cheaper than PIC simulations, and is suitable for "online use" in Control rooms. Furthermore it provides the second moments of matched distributions.
	Poster THBP34 [0.840 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP34
About •	Received ※ 30 September 2023 — Revised ※ 03 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 31 October 2023
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THBP35	Analysis Tools for Numerical Simulations of Dynamic Aperture with Xsuite	collider, dynamic-aperture, hadron, framework	551
	T. Pugnat, M. Giovannozzi, F.F. Van der Veken CERN, Meyrin, Switzerland D. Di Croce EPFL, Lausanne, Switzerland
	Recently, several efforts have been made at CERN to develop a new tracking tool, Xsuite, which is intended to be the successor to SixTrack. In this framework, analysis tools have also been prepared with the goal of providing advanced post-processing techniques for the interpretation of dynamic aperture simulations. The proposed software suite, named Xdyna, is meant to be a successor to the existing SixDesk environment. It incorporates all recent approaches developed to determine the dynamic aperture for a fixed number of turns. It also enables studying the time evolution of the dynamic aperture and the fitting of rigorous models based on the stability-time estimate provided by the Nekhoroshev theorem. These models make it possible to link the dynamic aperture to beam lifetime, and thus provide very relevant information for the actual performance of particle colliders. These tools have been applied to studies related to the luminosity upgrade of the CERN Large Hadron Collider (HL-LHC), the results of which are presented here.
	Poster THBP35 [0.514 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP35
About •	Received ※ 28 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 11 October 2023
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THBP36	Study of the Performance of the CERN Proton Synchrotron Internal Dump	beam-losses, proton, vacuum, synchrotron	555
	T. Pugnat, L.S. Esposito, M. Giovannozzi, C. Hernalsteens, A. Huschauer, S. Niang CERN, Meyrin, Switzerland D. Domange, E. Gnacadja, R. Tesse ULB, Bruxelles, Belgium
	In the framework of the LHC Injector Upgrade project, a new internal dump for the CERN Proton Synchrotron (PS) has been designed, installed, and successfully commissioned. This device is meant to move rapidly into the beam and stop charged particles over several turns to provide protection to the PS hardware against beam-induced damage. The performance of the dump should ensure efficient use throughout the PS energy range, i.e. from injection at 2 GeV (kinetic energy) to flat top at 26 GeV (total energy). In this paper, detailed numerical simulations are presented, carried out with a combination of sophisticated beam dynamics and beam-matter interaction codes, assessing the behaviour of stopped or scattered particles. The results of these numerical simulations are compared with the data collected during the routine operation of the PS and its internal dump.
	Poster THBP36 [0.609 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP36
About •	Received ※ 26 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 28 October 2023
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THBP37	Refining the LHC Longitudinal Impedance Model	impedance, cavity, injection, damping	559
	M. Zampetakis, T. Argyropoulos, Y. Brischetto, R. Calaga, L. Giacomel, B.E. Karlsen-Bæck, I. Karpov, I. Karpov, N. Mounet, B. Salvant, H. Timko CERN, GENEVA, Switzerland B.E. Karlsen-Bæck INFN-Roma, Roma, Italy
	Modelling the longitudinal impedance for the Large Hadron Collider (LHC) has been a long-standing effort, especially in view of its High-Luminosity (HL) upgrade. The resulting impedance model is an essential input for beam dynamics studies. Increased beam intensities in the HL-LHC era will pose new challenges like RF power limitations, beam losses at injection and coupled-bunch instabilities throughout the acceleration cycle. Starting from the existing longitudinal impedance model, effort has been made to identify the main contributing devices and improve their modelling. Loss of Landau damping (LLD) simulations are performed to investigate the dependence of the stability threshold on the completeness of the impedance model and its broad-band cut-off frequency. Plans to perform beam measurements to estimate the cut-off frequency, by investigating the LLD threshold in operation, are also discussed.
	Poster THBP37 [5.606 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP37
About •	Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 14 October 2023
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THBP45	Longitudinal Collective Effects at Beam Transfer from PS to SPS at CERN	beam-loading, impedance, injection, cavity	587
	A. Lasheen, H. Damerau, I. Karpov, G. Papotti, E.T. Vinten CERN, Meyrin, Switzerland
	The hardware upgrades of the LHC Injectors Upgrade (LIU) project at CERN were completed during the Long Shutdown 2 (2019-2021) to prepare the injectors for the beams required by the High Luminosity (HL) LHC. Doubling the bunch intensity leads to new challenges due to collective effects. Although many bottlenecks were already solved, a remaining limitation is the important loss of particles at transfer from the Proton Synchrotron (PS) to the Super Proton Synchrotron (SPS). The maximum transmission achieved since the restart in 2021 is in the order of 90%, yet leading to unnecessary activation of the SPS. The losses are distributed at various instants of the SPS cycle: fast intensity decay right after injection, slow losses along the injection plateau while waiting for multiple injections from the PS, and uncaptured beam removed at start of acceleration. In this contribution, the focus is on longitudinal aspects of transfer losses and more specifically on intensity effects during the non-adiabatic bunch shorting performed in the PS prior to extraction, as well as on the longitudinal mismatch at injection due to misaligned bunch phases in the SPS caused by transient beam loading.
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP45
About •	Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 15 October 2023
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THBP46	Simulation of the ESS Proton Beam Window Scattering	target, scattering, proton, ion-source	591
	E.D. Fackelman, E. Adli, H.E. Gjersdal, K.N. Sjobak University of Oslo, Oslo, Norway Y. Levinsen, A. Takibayev, C.A. Thomas ESS, Lund, Sweden
	The European Spallation Source produces neutrons used for science by delivering a 5MW proton beam to a tungsten target. The proton beam parameters must remain within a well-defined range during all phases of facility exploitation. The proton beam parameters are measured and monitored by an instrumentation suite, among which are two beam imaging systems. Parameters such as position and beam current density can be calculated from the images, supporting beam tuning and operation. However, one of the two systems may be affected by beam scattering. In this paper, we will focus on modelling the impact of the scattering on the beam on target distribution. The modelling process, involving simulation codes such as Geant4 and two-dimensional convolution in Matlab, is described. Initially, Geant4 simulates a scattered pencil beam. The resulting distribution is fitted and can be used similarly to an instrument response in image processing to model any possible beam distribution. Finally, we discuss the results of the scattered beam imaging model, showing the range of applications of the model and the impact of scattering on the beam parameters.
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP46
About •	Received ※ 01 October 2023 — Revised ※ 09 October 2023 — Accepted ※ 14 October 2023 — Issued ※ 21 October 2023
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THBP47	Studies on the Effect of Beam-Coupling Impedance on Schottky Spectra of Bunched Beams	impedance, synchrotron, coupling, diagnostics	595
	C. Lannoy, D. Alves, K. Łasocha, N. Mounet CERN, Meyrin, Switzerland C. Lannoy, T. Pieloni EPFL, Lausanne, Switzerland
	Schottky monitors can be used for non-invasive beam diagnostics to estimate various bunch characteristics, such as tune, chromaticity, bunch profile or synchrotron frequency distribution. However, collective effects, in particular beam-coupling impedance, can significantly affect Schottky spectra when large bunch charges are involved. In such conditions, the available interpretation methods are difficult to apply directly to the measured spectra, thus preventing the extraction of beam and machine parameters, which is possible for lower bunch charges. To study the impact of impedance on such spectra, we perform here time-domain, macro-particle simulations and apply a semi-analytical method to compute the Schottky signal for various machine and beam conditions, including those corresponding to typical physics operation at the Large Hadron Collider. This study provides preliminary interpretations of the impact of beam-coupling impedance on Schottky spectra by incorporating longitudinal and transverse resonator-like impedance models into the simulations.
	Poster THBP47 [1.133 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP47
About •	Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 21 October 2023
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THBP59	Tomographic Longitudinal Phase Space Reconstruction of Bunch Compression at ISIS	synchrotron, proton, operation, extraction	625
	B.S. Kyle, H.V. Cavanagh, A. Seville, R.E. Williamson STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	ISIS is an 800 MeV, high intensity, rapid-cycling synchrotron (RCS) used as a driver for a spallation neutron and muon spectroscopy (¿SR) facility. The intensity-limited beam and RCS operation at ISIS poses significant challenges, with non-adiabatic acceleration and space charge forces resulting in distortions to the Hamiltonian longitudinal dynamics. Effective modelling of the machine and benchmarking of models with beam measurements is essential both to improving machine performance, and to the development of the proposed ISIS II facility. The tomographic principle is a well-established tool for the reconstruction of the longitudinal phase space (LPS) of synchrotron beams. Is it operationally desirable for the ISIS accelerator to provide longitudinally compressed proton beams for ¿SR instrumentation. A new bunch compression scheme has been developed and validated using tomography. A reconstruction of the LPS of the ISIS high-intensity proton beam is presented, along with accompanying benchmarking measurements and beam physics simulations.
	Poster THBP59 [0.907 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP59
About •	Received ※ 01 October 2023 — Revised ※ 09 October 2023 — Accepted ※ 20 October 2023 — Issued ※ 25 October 2023
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FRA2I1	Summary of the Working Group A: Beam Dynamics in Rings	space-charge, resonance, experiment, impedance	662
	H. Bartosik, G. Rumolo CERN, Meyrin, Switzerland J.-L. Vay LBNL, Berkeley, California, USA N. Wang IHEP, Beijing, People’s Republic of China
	The HB-2023 workshop at CERN from October 9 to 13, 2023 is the continuation of the series of workshops, which started in 2002 at FNAL and rotates every two years between America, Europe and Asia. This contribution summarises the main highlights from Working Group A, Beam Dynamics in Rings, in terms of progress and challenges in the achievement of ever higher intensity and brightness hadron beams in accelerator rings around the world.
	Slides FRA2I1 [4.325 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-FRA2I1
About •	Received ※ 04 December 2023 — Accepted ※ 05 December 2023 — Issued ※ 01 January 2024
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FRA2I2	Summary of the Working Group B	linac, space-charge, rfq, operation	666
	N.J. Evans ORNL RAD, Oak Ridge, Tennessee, USA F. Bouly LPSC, Grenoble Cedex, France H.W. Zhao IMP/CAS, Lanzhou, People’s Republic of China
	Summary of the Working Group on Beam Dynamics in Linacs.
	Slides FRA2I2 [1.306 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-FRA2I2
About •	Received ※ 23 November 2023 — Accepted ※ 29 November 2023 — Issued ※ 24 January 2024
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FRA2I5	Summary of Working Group E: Instrumentation and Intercepting Devices	target, radiation, instrumentation, operation	677
	P. Forck GSI, Darmstadt, Germany P. Hurh Fermilab, Batavia, Illinois, USA K. Satou KEK, Tokai, Ibaraki, Japan
	The talk concerns the summary of the Working Group E related to Instrumentation and Intercepting Devices
	Slides FRA2I5 [6.640 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-FRA2I5
About •	Received ※ 26 November 2023 — Accepted ※ 29 November 2023 — Issued ※ 13 January 2024
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Paper

Title

Other Keywords

Page

Effect of Three-Dimensional Quadrupole Magnet Model on Beam Dynamics in the FODO Line at the Spallation Neutron Source Beam Test Facility

quadrupole, neutron, permanent-magnet, HOM

65

T.E. Thompson
ORNL RAD, Oak Ridge, Tennessee, USA
A.V. Aleksandrov, T.V. Gorlov, K.J. Ruisard, A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA

Funding: Supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics. Authored by UT- Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.
The research program at the Spallation Neutron Source (SNS) Beam Test Facility (BTF) focuses on improving accelerator model accuracy. This study explores the effect of two different models of permanent magnet quadrupoles, which comprise a 9.5-cell FODO line in the BTF. The more realistic model includes all higher-order terms, while the simple, in use model, is a perfect quadrupole. Particular attention is paid to high-amplitude particles to understand how the choice of quadrupole model will affect beam halo distributions. In this paper, we compare particle tracking through a FODO line that contains only linear terms - a perfect quadrupole model - to a full 3D model.

Slides TUC1C1 [1.705 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC1C1

About •

Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 27 October 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUC1C2

The Impact of High-Dimensional Phase Space Correlations on the Beam Dynamics in a Linear Accelerator

rfq, linac, MEBT, LEBT

68

A.M. Hoover, A.V. Aleksandrov, S.M. Cousineau, K.J. Ruisard, A.P. Shishlo, A.P. Zhukov
ORNL, Oak Ridge, TN, USA

Hadron beams develop intensity-dependent transverse-longitudinal correlations within radio-frequency quadrupole (RFQ) accelerating structures. These correlations are only visible in six-dimensional phase space and are destroyed by reconstructions from low-dimensional projections. In this work, we estimate the effect of artificial decorrelation on the beam dynamics in the Spallation Neutron Source (SNS) linac and Beam Test Facility (BTF). We show that the evolution of a realistic initial distribution and its decorrelated twin converge during the early acceleration stages; thus, low-dimensional projections are probably sufficient for detailed predictions in high-power linacs.

Slides TUC1C2 [6.573 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC1C2

About •

Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 13 October 2023

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUA2I1

Xsuite: An Integrated Beam Physics Simulation Framework

optics, space-charge, radiation, lattice

73

G. Iadarola, A. Abramov, X. Buffat, R. De Maria, D. Demetriadou, L. Deniau, P.D. Hermes, P. Kicsiny, P.M. Kruyt, A. Latina, S. Łopaciuk, L. Mether, K. Paraschou, T. Pieloni, G. Sterbini, F.F. Van der Veken
CERN, Meyrin, Switzerland
P. Belanger
UBC & TRIUMF, Vancouver, British Columbia, Canada
D. Di Croce, M. Seidel, L. van Riesen-Haupt
EPFL, Lausanne, Switzerland
P.J. Niedermayer
GSI, Darmstadt, Germany

Xsuite is a newly developed modular simulation package combining in a single flexible and modern framework the capabilities of different tools developed at CERN in the past decades, notably Sixtrack, Sixtracklib, COMBI and PyHEADTAIL. The suite is made of a set of python modules (Xobjects, Xparts, Xtrack, Xcoll, Xfields, Xdpes) that can be flexibly combined together and with other accelerator-specific and general-purpose python tools to study complex simulation scenarios. The code allows for symplectic modeling of the particle dynamics, combined with the effect of synchrotron radiation, impedances, feedbacks, space charge, electron cloud, beam-beam, beamstrahlung, electron lenses. For collimation studies, beam-matter interaction is simulated using the K2 scattering model or interfacing Xsuite with the BDSIM/Geant4 library. Tools are available to compute the accelerator optics functions from the tracking model and to generate particle distributions matched to the optics. Different computing platforms are supported, including conventional CPUs, as well as GPUs from different vendors.

Slides TUA2I1 [4.388 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA2I1

About •

Received ※ 30 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 22 October 2023

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TUA2I2

Community Modeling Tools for High Brightness Beam Physics

space-charge, interface, framework, plasma

81

C.E. Mitchell, M. Garten, A. Huebl, R. Lehé, J. Qiang, R.T. Sandberg, J.-L. Vay
LBNL, Berkeley, California, USA

Pushing accelerator technology toward operation with higher intensity hadron beams is critical to meet the needs of future colliders, spallation neutron sources, and neutrino sources. To understand the dynamics of such beams requires a community effort with a comprehensive approach to modeling, from the source to the end of the beam lifetime. One needs efficient numerical models with high spatial resolution and particle statistics, insensitivity to numerical noise, and the ability to resolve low-density halo and particle loss. To meet these challenges, LBNL and collaborators have seeded an open ecosystem of codes, the Beam pLasma & Accelerator Simulation Toolkit (BLAST), that can be combined with each other and with machine learning frameworks to enable integrated start-to-end simulation of accelerator beamlines for accelerator design. Examples of BLAST tools include the PIC codes WarpX and ImpactX. These codes feature GPU acceleration and mesh-refinement, and have openPMD standardized data I/O and a Python interface. We describe these tools and the advantages that open community standards provide to inform the modeling and operation of future high-brightness accelerators.

Slides TUA2I2 [13.597 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA2I2

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Received ※ 03 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 01 November 2023

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TUA2C2

Recent Advances in the CERN PS Impedance Model and Instability Simulations

impedance, kicker, proton, synchrotron

86

S. Joly
La Sapienza University of Rome, Rome, Italy
G. Iadarola, N. Mounet, B. Salvant, C. Zannini
CERN, Meyrin, Switzerland
M. Migliorati
INFN-Roma1, Rome, Italy

Transverse instability growth rates in the CERN Proton Synchrotron are studied thanks to the recently updated impedance model of the machine. Using this model, macroparticle tracking simulations were performed with a new method well-suited for the slicing of short wakes, which achieves comparable performance to the originally implemented method while reducing the required number of slices by a factor of 5 to 10. Dedicated beam-based measurement campaigns were carried out to benchmark the impedance model. Until now, the model underestimated instability growth rates at injection energy. Thanks to a recent addition to the impedance model, namely the kicker magnets¿ connecting cables and their external circuits, the simulated instability growth rates are now comparable to the measured ones.

Slides TUA2C2 [0.736 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA2C2

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Received ※ 28 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 21 October 2023

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TUC2C1

Beam Physics Simulation Studies of 70 Mev ISIS Injector Linac

linac, operation, MEBT, DTL

97

S.A. Ahmadiannamin, H.V. Cavanagh, S.R. Lawrie, A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The ISIS neutron spallation source is a pioneering research infrastructure in the field of high intensity accelerator physics, catering to scientific users. Comprising a 70 MeV injector linac and an 800 MeV Rapid cycling synchrotron with two beam targets, this facility has witnessed significant upgrades in recent years, leading to enhanced transmission efficiency. Further optimization efforts are underway to ensure continuous improvement. This article focuses on beam physics simulation studies conducted on the current ISIS linac, aiming to gain a deeper understanding and analysis of various phenomena observed during routine operations and accelerator physics experimentation. By examining these phenomena, valuable insights can be obtained to inform the future development of high efficiency injector of ISIS-II.

Slides TUC2C1 [6.467 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC2C1

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Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 13 October 2023

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TUC2C2

Evaluating PyORBIT as Unified Simulation Tool for Beam-Dynamics Modeling of the ESS Linac

lattice, DTL, EPICS, space-charge

102

J.F. Esteban Müller, Y. Levinsen, N. Milas, C.Z. Zlatanov
ESS, Lund, Sweden
A.P. Shishlo, A.P. Zhukov
ORNL, Oak Ridge, Tennessee, USA

The design of the ESS proton linac was supported by the simulation code TraceWin, a closed-source commercial software for accurate multiparticle simulations. Conversely, the high-level physics applications used for beam commissioning and machine tuning rely on the Open XAL framework and its online model for fast envelope simulations. In this paper, we evaluate PyORBIT for both online modeling of the linac for machine commissioning and tuning as well as for more accurate offline simulations for beam-dynamics studies. We present the modifications done to the code to adapt it to this use case, namely porting the code to Python 3, adding an envelope tracker, and integrating with the EPICS control systems. Finally, we show the results of benchmarking PyORBIT against our current modeling tools.

Slides TUC2C2 [0.886 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC2C2

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Received ※ 08 October 2023 — Revised ※ 09 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 14 October 2023

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TUA3I2

Measurements of Momentum Halo Due to the Reduced RFQ Voltage During the LIPAc Beam Commissioning

rfq, MMI, operation, cryomodule

112

K. Hirosawa, A. De Franco, K. Hasegawa, K. Kondo, S. Kwon, K. Masuda, A. Mizuno, M. Sugimoto
QST Rokkasho, Aomori, Japan
F. Bénédetti
CEA-DRF-IRFU, France
Y. Carin, H. Dzitko, D. Gex, I. Moya, F. Scantamburlo
F4E, Germany
J.C. Morales Vega
Consorcio IFMIF-DONES España, Granada, Spain
I. Podadera
CIEMAT, Madrid, Spain

The Linear IFMIF Prototype Accelerator, LIPAc, is being commissioned aiming in particular at validating the RFQ up to 5MeV beam acceleration. Eventually, the nominal beam of 5 MeV-125 mA in 1 ms/1 Hz pulsed mode was achieved in 2019. The beam operation has been resumed since July 2023 after long maintenance including recovery from unexpected problems in the RFQ RF system. This new phase aims at the commissioning of the full configuration except SRF linac, which is replaced by a temporary beam transport line. Focusing on the RFQ behavior, it will be interesting to operate it at higher duty especially for longer pulses. Indeed, a beam simulation study suggested that the beam extracted from the RFQ includes considerable momentum halo when the RFQ voltage reduces by a few percent, with a slight decrease of mean energy. It can be a potential source of quench like the mismatched beam in the cryomodule. This could be studied measuring the energy from the Time-of-Flight among multiple BPMs while monitoring beam loss around the dipole, where momentum halo should be lost. During the upcoming commissioning, we propose to study them by scanning the RFQ voltage.

Slides TUA3I2 [4.465 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA3I2

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Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 29 October 2023

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TUA4I2

1-MW Beam Operation at J-PARC RCS with Minimum Beam Loss

injection, operation, beam-losses, scattering

147

P.K. Saha, H. Harada, H. Hotchi, K. Okabe, H. Okita, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The 3-GeV RCS of J-PARC now operates at high-intensity to nearly the designed 1 MW beam. The beam loss and the corresponding residual radiation is one of the key limitations against beam intensity ramp up. Recently, by a series of beam studies and feedback from numerical simulations, we have well mitigated the beam loss to a minimum level and also reduced the beam emittances for beam operation to the spallation neutron source as well as to the main ring. The residual beam loss at the designed 1 MW beam power occurs mostly due to the unavoidable foil scattering beam loss during multi-turn injection, while other beam loss sources have been well mitigated to realize a stable and higher availability beam operation at a nearly 1 MW beam power.

Slides TUA4I2 [2.303 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA4I2

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Received ※ 02 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 21 October 2023

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TUC4I1

A Kicker Impedance Reduction Scheme with Diode Stack and Resistor at the RCS in J-PARC

kicker, impedance, emittance, extraction

162

Y. Shobuda, H. Harada, P.K. Saha, T. Takayanagi, F. Tamura, T. Togashi, Y. Watanabe, K. Yamamoto, M. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

At the 3-GeV Rapid Cycling Synchrotron (RCS) within the Japan Proton Accelerator Research Complex (J-PARC), kicker impedance causes beam instability. A 1-MW beam with a large emittance can be delivered to the Material and Life Science Experimental Facility (MLF) by suppressing beam instabilities without the need for a transverse feedback system¿simply by turning off the sextuple magnets. However, we require other high-intensity and high-quality beams with smaller emittances for the Main Ring (MR). To address this, we proposed a scheme for suppressing the kicker impedance using a diode stack and resistors, which effectively reduces beam instability. Importantly, these devices have a negligible effect on the extracted beam from the RCS.

Slides TUC4I1 [2.713 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC4I1

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Received ※ 26 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 10 October 2023

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TUC4I2

Development of an Impedance Model for the ISIS Synchrotron and Predictions for the Head-Tail Instability

impedance, kicker, synchrotron, coupling

170

D.W. Posthuma de Boer, B.A. Orton, C.M. Warsop, R.E. Williamson
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

ISIS is a pulsed, spallation neutron and muon source at the Rutherford Appleton Laboratory in the UK. The rapid cycling synchrotron which drives the facility accelerates 3·10¹³ protons-per-pulse from 70 to 800 MeV at 50 Hz, and delivers a mean beam power of 0.2 MW to two target stations. Beam-loss mechanisms must be understood to optimise performance and minimise equipment activation; and to develop mitigation methods for future operations and new accelerators. Substantial beam-losses are driven by a vertical head-tail instability, which has also limited beam intensity. Beam-based impedance measurements suggest the instability is driven by a low-frequency narrowband impedance, but its physical origin remains unknown. More generally, research into the nature of the instability is hindered without a detailed transverse impedance model. This paper presents a survey of vertical impedance estimates for ISIS equipment, using analytical methods, low frequency CST simulations and lab-based coil measurements. The final impedance estimate is then used as an input to a new linearised Vlasov solver, and predicted growth rates compared with previously obtained experimental results.

Slides TUC4I2 [4.374 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC4I2

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Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 31 October 2023

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TUC4C1

Beam Coupling Impedance of the Main Extraction Kickers in the CERN PS

impedance, kicker, coupling, extraction

178

M. Neroni, M.J. Barnes, A. Lasheen, C. Vollinger
CERN, Meyrin, Switzerland
A. Mostacci
Sapienza University of Rome, Rome, Italy
B.K. Popovic
ANL, Lemont, Illinois, USA

In view of the High Luminosity (HL) upgrade of the LHC, the beam intensity must be doubled in the injector chain. To perform reliable beam dynamics simulations, the beam coupling impedance in the injectors, such as the Proton Synchrotron (PS), must be followed closely by including all contributing elements into the impedance model. The existing kicker magnets of the PS had been optimized for large kick strength and short rise/fall times, but not necessarily to minimise beam coupling impedance. Hence, unwanted beam induced voltage can build up in their electrical circuits, with an impact on the beam. The beam coupling impedances of the two main kicker magnets used for the fast extraction from PS, the KFA71 and KFA79, are extensively characterized in this study. In particular, electromagnetic simulation results for the longitudinal and transverse coupling impedance are shown. The critical impedance contributions are identified, and their effect on beam stability is discussed. Moreover, the impact of the cable terminations on the electromagnetic field pattern and possible mitigation techniques are presented, providing a complete impedance evaluation of the entire kicker installation.

Slides TUC4C1 [2.715 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC4C1

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Received ※ 30 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 15 October 2023

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TUC4C2

Mitigating Collimation Impedance and Improving Halo Cleaning with New Optics and Settings Strategy of the HL-LHC Betatron Collimation System

optics, impedance, collimation, experiment

183

B. Lindström, R. Bruce, X. Buffat, R. De Maria, L. Giacomel, P.D. Hermes, D. Mirarchi, N. Mounet, T.H.B. Persson, S. Redaelli, R. Tomás García, F.F. Van der Veken, A. Wegscheider
CERN, Meyrin, Switzerland

Funding: Work supported by the HL-LHC project
With High Luminosity Large Hadron Collider (HL-LHC) beam intensities, there are concerns that the beam losses in the dispersion suppressors around the betatron cleaning insertion might exceed the quench limits. Furthermore, to maximize the beam lifetime it is important to reduce the impedance as much as possible. The collimators constitute one of the main sources of impedance in HL-LHC, given the need to operate with small collimator gaps. To improve this, a new optics was developed which increases the beta function in the collimation area, as well as the single pass dispersion from the primary collimators to the downstream shower absorbers. Other possible improvements from orbit bumps, to further enhance the locally generated dispersion, and from asymmetric collimator settings were also studied. The new solutions were partially tested with 6.8 TeV beams at the LHC in a dedicated machine experiment in 2022. In this paper, the new performance is reviewed and prospects for future operational deployment are discussed.

Slides TUC4C2 [2.222 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC4C2

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Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 28 October 2023

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WEA1C1

Bunch-by-bunch Tune Shift Studies for LHC-type Beams in the CERN SPS

impedance, injection, wakefield, operation

194

I. Mases Solé, H. Bartosik, K. Paraschou, M. Schenk, C. Zannini
CERN, Meyrin, Switzerland

After the implementation of major upgrades as part of the LHC Injector Upgrade Project (LIU), the Super Proton Synchrotron (SPS) delivers high intensity bunch trains with 25 ns bunch spacing to the Large Hadron Collider (LHC). These beams are exposed to several collective effects in the SPS, such as beam coupling impedance, space charge and electron cloud, leading to relatively large bunch-by-bunch coherent and incoherent tune shifts. Tune correction to the nominal values at injection is crucial to ensure beam stability and good beam transmission. Measurements of the bunch-by-bunch coherent tune shifts have been performed under different beam conditions. In this paper, we present the measurements of the bunch-by-bunch tune shift as function of bunch intensity for trains of 72 bunches. The experimental data are compared to multiparticle tracking simulations (including other beam variants such as 8b4e beam and hybrid beams) using the SPS impedance model.

Slides WEA1C1 [2.613 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA1C1

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Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 09 October 2023

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WEA2I2

Space Charge Induced Resonances and Suppression in J-PARC MR

resonance, optics, space-charge, operation

222

T. Yasui
KEK, Tokai, Ibaraki, Japan

In the main ring synchrotron (MR) of Japan Proton Accelerator Research Complex (J-PARC), space charge induced resonances are the cause of beam losses. Although we have scanned the tunes to minimize beam losses, it has been difficult to completely avoid high order structure resonances because the MR has only three super-periodicities. In the present settings for the neutrino operation, we identified that the space charge induced resonance 8ny=171 is the main source of beam losses, except for random resonances. We found that this resonance can be suppressed by beam optics modification while maintaining the tune. In this talk, we present the theoretical, simulation, and experimental results showing the advantages of the new beam optics and the reasons for them.

Slides WEA2I2 [6.189 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2I2

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Received ※ 07 November 2023 — Accepted ※ 18 November 2023 — Issued ※ 29 November 2023

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WEA2C1

Tune Optimization for Alleviating Space Charge Effects and Suppressing Beam Instability in the RCS of CSNS

space-charge, resonance, acceleration, ECR

228

S.Y. Xu, L. Huang, M.Y. Huang, Y. Li, S. Wang
IHEP, Beijing, People’s Republic of China

The design betatron tune of the Rapid Cycling Synchrotron (RCS) of China Spallation Neutron Source (CSNS) is (4.86, 4.80), which allows for incoherent tune shifts to avoid serious systematic betatron resonances. When the operational bare tune was set at the design value, serious beam instability in the horizontal plane and beam loss induced by half-integer resonance in the vertical plane under space charge detuning were observed. The tunes over the whole acceleration process are optimized based on space charge effects and beam instability. In the RCS, manipulating the tune during the beam acceleration process is a challenge due to the quadrupole magnets being powered by resonant circuits. In the RCS of CSNS, a method of waveform compensation for RCS magnets was investigated to accurately manipulate the magnetic field ramping process. The optimized tune pattern was able to well control the beam loss induced by space charge and beam instability. The beam power of CSNS achieved the design value of 100 kW with small uncontrolled beam loss.

Slides WEA2C1 [4.710 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2C1

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Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 23 October 2023

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WEC2C1

Evaluation of Power Deposition in HL-LHC with Crystal-assisted Heavy Ion Collimation

collimation, heavy-ion, operation, betatron

236

V. Rodin, R. Bruce, R. Cai, M. D’Andrea, L.S. Esposito, A. Lechner, J.B. Potoine, S. Redaelli, J. Schoofs
CERN, Meyrin, Switzerland
R. Cai
EPFL, Lausanne, Switzerland
J.B. Potoine
IES, Montpellier, France

The future LHC heavy-ion program, utilizing 208Pb⁸²⁺ beams at up to 7 Z TeV, is anticipated to operate with substantial intensity upgrade. During periods of short beam lifetime, a potential performance limitation may arise from secondary ions produced by electromagnetic dissociation and hadronic fragmentation in the collimators of the betatron cleaning insertion. These off-rigidity fragments risk quenching superconducting magnets when they are lost in the dispersion suppressor. To address this concern, an alternative collimation scheme will be introduced for forthcoming heavy ion runs, employing bent channeling crystals as primary collimators. In this contribution, we detail a thorough study of power deposition levels in superconducting magnets through FLUKA shower simulations in the crystal-based collimation system. The study focuses on the downstream dispersion suppressor regions of the betatron cleaning insertion, where the quench risk is the highest. Based on this work, we quantify the expected quench margin in future runs with 208Pb⁸²⁺ beams, providing crucial insights for the successful execution of the upgraded heavy-ion program at the HL-LHC.
Research supported by the HL-LHC project.

Slides WEC2C1 [3.105 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC2C1

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Received ※ 24 November 2023 — Revised ※ 25 November 2023 — Accepted ※ 29 November 2023 — Issued ※ 16 January 2024

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WEA3C1

The Tracking Code RF-Track and Its Application

electron, linac, positron, space-charge

245

A. Latina
CERN, Meyrin, Switzerland

RF-Track is a CERN-developed particle tracking code that can simulate the generation, acceleration, and tracking of beams of any species through an entire accelerator, both in realistic field maps and conventional elements. RF-Track includes a large set of single-particle and collective effects: space-charge, beam-beam, beam loading in standing and travelling wave structures, short- and long-range wakefield effects, synchrotron radiation emission, multiple Coulomb scattering in materials, and particle lifetime. These effects make it the ideal tool for the simulation of high-intensity machines. RF-Track has been used for the simulation of electron linacs for medical applications, inverse-Compton-scattering sources, positron sources, protons in Linac4, and the cooling channel of a future muon collider. An overview of the code is presented, along with some significant results.

Slides WEA3C1 [2.696 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA3C1

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Received ※ 26 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 12 October 2023

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WEA3C2

Benchmarking of PATH and RF-Track in the Simulation of Linac4

space-charge, linac, DTL, emittance

249

G. Bellodi, J.-B. Lallement, A. Latina, A.M. Lombardi
CERN, Meyrin, Switzerland

A benchmarking campaign has been initiated to compare PATH and RF-Track in modelling high-intensity, low-energy hadron beams. The development of extra functionalities in RF-Track was required to handle an unbunched beam from the source and to ease the user interface. The Linac4 RFQ and downstream accelerating structures were adopted as test case scenarios. This paper will give an overview of the results obtained so far and plans for future code development.

Slides WEA3C2 [4.809 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA3C2

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Received ※ 27 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 18 October 2023

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WEA3C3

Differential Algebra for Accelerator Optimization with Truncated Green’s Function

space-charge, framework, multipole, operation

254

C.S. Park
Korea University Sejong Campus, Sejong, Republic of Korea

Accelerator optimization is a critical problem in the design of high-performance particle accelerators. The truncated Green’s function space charge algorithm is a powerful tool for simulating the effects of space charge in accelerators. However, the truncated Green’s function algorithm can be computationally expensive, especially for large accelerators. In this work, we present a new approach to accelerator optimization using differential algebra with the truncated Green’s function space charge algorithm. Our approach uses differential algebra to symbolically represent the equations of the truncated Green’s function algorithm. This allows us to perform efficient symbolic analysis of the equations, which can be used to identify and optimize the accelerator parameters. We demonstrate the effectiveness of our approach by applying it to the optimization of a linear accelerator. We show that our approach can significantly reduce the computational cost of the truncated Green’s function algorithm, while still achieving high accuracy.

Slides WEA3C3 [0.772 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA3C3

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Received ※ 28 September 2023 — Revised ※ 11 October 2023 — Accepted ※ 14 October 2023 — Issued ※ 18 October 2023

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WEC3C3

Simulations and Measurements of Betatron and Off-momentum Cleaning Performance in the Energy Ramp at the LHC

collimation, betatron, injection, optics

279

N. Triantafyllou, R. Bruce, M. D’Andrea, K.A. Dewhurst, B. Lindström, D. Mirarchi, S. Redaelli, F.F. Van der Veken
CERN, Meyrin, Switzerland

The Large Hadron Collider (LHC) is equipped with a multistage collimation system that protects the machine against unavoidable beam losses at large betatron and energy offsets at all stages of operation. Dedicated validations and an understanding in simulations of the collimation performance are crucial for the energy ramp from 450 GeV to 6.8 TeV because complex changes of optics and orbit take place in this phase. Indeed, the betatron functions are reduced in all experiments for an efficient setup of the collisions at top energy. In this paper, simulations of the betatron and off-momentum cleaning during the energy ramp are presented. A particular focus is given to the off-momentum losses at the start of the ramp. The simulation results are benchmarked against experimental data, demonstrating the accuracy of the newly developed tools used for the simulations.

Slides WEC3C3 [1.641 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC3C3

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Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 19 October 2023

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WEA4I1

Development of Non-Destructive Beam Envelope Measurements Using BPMs for Low Beta Heavy Ion Beams in SRF Cavities

cavity, emittance, quadrupole, heavy-ion

284

T. Nishi, O. Kamigaito, N. Sakamoto, T. Watanabe, K. Yamada
RIKEN Nishina Center, Wako, Japan
T. Adachi
RIKEN, Saitama, Japan

Accurate measurement and control of the beam envelope are crucial issues, particularly in high-power accelerator facilities. However, the use of destructive monitors is limited to low-intensity beams. Furthermore, in the case of beam transport between superconducting cavities, these destructive monitors are avoided to prevent the generation of dust particles and outgassing. In the Superconducting RIKEN LINAC, or SRILAC [1], we utilize 8 non-destructive Beam Energy Position Monitors (BEPMs)[2] to measure beam positions and energies. Recently we are developing a method for estimating the beam envelope by combining the quadrupole moments from BEPMs, which consist of four cosine-shape electrodes, with transfer matrix[3]. While this method has been applied to electron and proton beams, it has not been practically demonstrated for heavy ion beams in beta ¿0.1 regions. By combining BEPM simulations, we are making progress toward the reproduction of experimental results, overcoming specific issues associated with low beta. This development will present the possibility of a new method for beam envelope measurement in LEBT and MEBT, especially for hadron beam facilities.
[1] K. Yamada et al., in Proc. SRF2021, paper MOOFAV01(2021).
[2] T. Watanabe et al., in Proc. IBIC2020, paper FRAO04 (2020).
[3] R. H. Miller et al., in Proc. HEAC¿83, pp. 603¿605 (1983).

Slides WEA4I1 [10.867 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA4I1

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Received ※ 12 October 2023 — Revised ※ 13 October 2023 — Accepted ※ 18 October 2023 — Issued ※ 01 November 2023

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WEA4I2

Linac4 Source and Low Energy Experience and Challenges

rfq, emittance, linac, solenoid

290

E. Sargsyan, G. Bellodi, F.D.L. Di Lorenzo, J. Etxebarria, J.-B. Lallement, A.M. Lombardi, M. O’Neil
CERN, Meyrin, Switzerland

At the end of Long Shutdown 2 (LS2), in 2020 Linac4 became the new injector of CERN’s proton accelerator complex. The previous version of the Linac4 H⁻ ion source (IS03), produced an operational pulsed peak beam current of 35 mA, resulting in 27 mA after the Radio-Frequency Quadrupole (RFQ). This limited transmission was mainly due to the extracted beam emittance exceeding the acceptance of the RFQ. A new geometry of the Linac4 source extraction electrodes has been developed with the aim of decreasing the extracted beam emittance and increasing the transmission through the RFQ. The new source (IS04) has been studied and thoroughly tested at the Linac4 source test stand. At the start of the 2023 run, the IS04 was installed as operational source in the Linac4 tunnel and is being successfully used for operation with 27 mA peak current after the RFQ. During high-intensity tests, the source, the linac, and the transfer-line to the Proton Synchrotron Booster (PSB) were also tested with a peak beam current of up to 50 mA from the source resulting in 35 mA at the PSB injection. This paper discusses the recent developments, tests, and future plans for the Linac4 H⁻ ion source.

Slides WEA4I2 [2.217 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA4I2

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Received ※ 27 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 29 October 2023

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WEA4C2

Beam Loss Simulations for the Proposed TATTOOS Beamline at HIPA

target, proton, cyclotron, septum

300

M. Hartmann, D.C. Kiselev, D. Reggiani, M. Seidel, J. Snuverink, H. Zhang
PSI, Villigen PSI, Switzerland
M. Seidel
EPFL, Lausanne, Switzerland

IMPACT (Isotope and Muon Production with Advanced Cyclotron and Target Technology) is a proposed upgrade project for the high-intensity proton accelerator facility (HIPA) at the Paul Scherrer Institute (PSI). As part of IMPACT, a new radioisotope target station, TATTOOS (Targeted Alpha Tumour Therapy and Other Oncological Solutions) will allow to produce promising radionuclides for diagnosis and therapy of cancer in doses sufficient for clinical studies. The proposed TATTOOS beamline and target will be located near the UCN (Ultra Cold Neutron source) target area, branching off from the main UCN beamline. In particular, the 590 MeV proton beamline is intended to operate at a beam intensity of 100 uA (60 kW), requiring a continuous splitting of the main beam via an electrostatic splitter. Beam loss simulations to verify safe operation have been performed and optimised using BDSIM, a Geant4 based tool enabling the simulation of beam transportation through magnets and particle passage through accelerator. In this study, beam profiles, beam transmission and power deposits are generated and studied. Finally, a quantitative description of the beam halo is introduced.

Slides WEA4C2 [4.534 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA4C2

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Received ※ 29 September 2023 — Revised ※ 04 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 28 October 2023

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WEC4C2

Multiharmonic Buncher for the Isolde Superconducting Recoil Separator Project

ISOL, bunching, cavity, linac

321

J.L. Muñoz, I. Bustinduy, P.J. González, A. Kaftoosian, L.C. Medina, S. Varnasseri
ESS Bilbao, Zamudio, Spain
I. Martel
University of Huelva, Huelva, Spain

Funding: This work has been supported by the European Union ¿NextGenerationEU program
The ISOLDE Superconducting Recoil Separator (ISRS) is a proposal of building a very compact separator ring as an instrument in the HIE-ISOLDE facility. The injection of the HIE-ISOLDE beam into this ring requires a more compact bunch structure, so a Multi-Harmonic Buncher device is proposed for this task. The MHB will operate at a frequency of 10.128 MHz, which is a 10% of the linac frequency, and would be installed before the RFQ. The MHB is desgined as a two electrodes system, and the MHB signal, composed for the first four harmonics of the fundamental frequency, is fed into the electrodes that are connected to the central conductor of a coaxial waveguides. The full design of the MHB is presented, including electromagnetic optimization of the electrode shape, optimization of the weights of each of the harmonic contribution, mechanical and thermal design of the structure. The RF generation and electronics to power up the device are also presented. A solution that generates directly the composed signal andis then amplified by a solid state power amplifier is also presented in this contribution.

Slides WEC4C2 [4.165 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC4C2

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Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 27 October 2023

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THA1I1

Performance and Upgrade Considerations for the CSNS Injection

injection, MMI, neutron, proton

326

M.Y. Huang, S. Wang, S.Y. Xu
IHEP, Beijing, People’s Republic of China

Funding: This work is jointly supported by the National Natural Science Foundation of China (Nos. 12075134) and the Guangdong Basic and Applied Basic Research Foundation (No. 2021B1515120021).
For the proton synchrotron, the beam injection is one of the most important issues. Firstly, based on the China Spallation Neutron Source (CSNS), the injection methods have been comprehensively studied, including phase space painting and H⁻ stripping. In order to solve the key difficulties faced when the beam power exceeds 50% of the design value, flexibility in the CSNS design has been exploited to implement the correlated painting by using the rising current curve of the pulse power supply. The effectiveness of the new method has been verified in the simulation and beam commissioning. By using the new method, the beam power on the target has successfully risen to the design value. Secondly, for the CSNS upgrade, the injection energy is increased from 80 MeV to 300 MeV and the injection beam power is increased by about 19 times. Based on the CSNS experience and simulation results, it is hoped that the new injection scheme can not only be compatible with correlated and anti-correlated painting, but also greatly reduces the peak temperature of the stripping foil. After in-depth study, a new painting scheme has been proposed which has been verified to be feasible in the simulation.

Slides THA1I1 [2.951 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THA1I1

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Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 15 October 2023

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THA1I2

High-Intensity Studies on the ISIS RCS and Their Impact on the Design of ISIS-II

space-charge, operation, controls, impedance

331

R.E. Williamson, D.J. Adams, H.V. Cavanagh, B.S. Kyle, D.W. Posthuma de Boer, H. Rafique, C.M. Warsop
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

ISIS is the pulsed spallation neutron and muon source at the Rutherford Appleton Laboratory in the UK. Operation centres on a rapid cycling proton synchrotron (RCS) that accelerates 3·10¹³ protons per pulse from 70 MeV to 800 MeV at 50 Hz, delivering a mean beam power of 0.2 MW. As a high-intensity machine, research at ISIS is predominantly focused on understanding, minimising and controlling beam-loss, which is central to sustainable machine operation. Knowledge of beam-loss mechanisms then informs the design of future high power accelerators such as ISIS-II. This paper provides an overview of the R&D studies currently underway on the ISIS RCS and how these relate to ongoing work understanding and optimising designs for ISIS-II. In particular, recent extensive investigations into observed head-tail instabilities are summarised.

Slides THA1I2 [10.825 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THA1I2

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Received ※ 01 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 18 October 2023

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THA2C1

Measurement of Transverse Beam Emittance for a High-Intensity Proton Injector

solenoid, space-charge, emittance, beam-transport

363

D.-H. Kim, H.S. Kim, H.-J. Kwon, S. Lee
KOMAC, KAERI, Gyeongju, Republic of Korea

Funding: This work was supported through "KOMAC operation fund" of KAERI by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (KAERI-524320-23)
We propose a simple and fast diagnostics method for the transverse beam emittance using a solenoid magnet. The solenoid scan data is analyzed employing the hard edge solenoid model and thick lens approximation. The analytical method is validated by beam dynamics simulations with varying input beam parameters. To address the space charge effect in a simplified manner, the space charge force is linearized and incorporated between segments of the drift-solenoid transfer matrix. For intense hadron injectors with higher beam current accounting for space charge prove to be more effective for correction. Building upon the method validated through beam simulation, experiments are conducted on space charge compensation at the beam test stand in the Korea Multipurpose Accelerator Complex (KOMAC). In a constant ion source operating condition, beam emittance is measured from solenoid scans while varying the flow rate of krypton gas injection. Notable shifts are observed in transverse beam emittance attributable to krypton gas injection, implying some optimal gas flow rate for mitigating emittance growth.

Slides THA2C1 [3.438 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THA2C1

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Received ※ 23 October 2023 — Revised ※ 28 October 2023 — Accepted ※ 30 October 2023 — Issued ※ 20 November 2023

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THA2C2

Comparison of Longitudinal Emittance of Various RFQs

rfq, emittance, focusing, linac

368

M. Comunian, L. Bellan, A. Pisent
INFN/LNL, Legnaro (PD), Italy

In various projects a large variety of RFQs has been developed, for different application, with different average current, frequency, and energy range. On this article a comparison, in a scaled way, will be done, using the build RFQs of IFMIF, ESS, SPES, ANTHEM, PIAVE. On particular the beam dynamics characteristics will be analyzed, like transmission, output longitudinal emittance and real performance versus simulation.

Slides THA2C2 [6.261 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THA2C2

About •

Received ※ 30 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 16 October 2023

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THC2I2

Extraction of LHC Beam Parameters from Schottky Signals

synchrotron, betatron, diagnostics, octupole

382

K. Łasocha, D. Alves, C. Lannoy, N. Mounet
CERN, Meyrin, Switzerland
C. Lannoy, T. Pieloni
EPFL, Lausanne, Switzerland

Analysis of Schottky signals provides rich insights into the dynamics of a hadron beam, with well-established methods of deriving the betatron tune and machine chromaticity. In this contribution, we will report on recent developments in the analysis and understanding of the signals measured at the Large Hadron Collider during proton and Pb⁸²⁺ fills. A fitting-based technique, where the measured spectra are iteratively compared with theoretical predictions, will be presented and compared with the previous methods. As a step beyond the classical theory of Schottky spectra, certain signal modifications due to the activity of the LHC machine systems will be discussed from the perspective of the applicability of the modified signal to the beam diagnostics.

Slides THC2I2 [9.053 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THC2I2

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Received ※ 04 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 12 October 2023

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THC2C1

Shower Simulations for the CERN Proton Synchrotron Internal Dump and Comparison with Beam Loss Monitor Data

proton, flattop, closed-orbit, operation

389

S. Niang, L.S. Esposito, M. Giovannozzi, C. Hernalsteens, A. Huschauer, T. Pugnat
CERN, Meyrin, Switzerland
D. Domange
ULB, Bruxelles, Belgium

During the Long Shutdown 2 (LS2), two new internal dumps (TDIs) were installed and successfully put into operation in the CERN Proton Synchrotron (PS) to withstand the intense and bright beams produced for the High Luminosity LHC. TDIs serve as safety devices designed to rapidly enter the beam trajectory and stop the beam over multiple turns. Due to their design, the TDI only absorbs a fraction of the secondary particle shower produced by beam particles that impinge on it. Starting from impacts computed by multi-turn beam dynamics simulations, detailed shower simulations were performed with FLUKA to assess the radiation field’s impact on the downstream equipment, with a particular emphasis on the dose measured by Beam Loss Monitors. The numerical data obtained from the simulations are compared with the experimental data collected during PS operation.

Slides THC2C1 [2.092 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THC2C1

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Received ※ 28 September 2023 — Revised ※ 09 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 29 October 2023

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THAFP01

Probing Transverse Impedances in the High Frequency Range at the CERN SPS

impedance, betatron, optics, coupling

393

E. de la Fuente, H. Bartosik, I. Mases Solé, G. Rumolo, C. Zannini
CERN, Meyrin, Switzerland

Funding: CERN
The SPS transverse impedance model, which includes the major impedance contributions in the machine, can be benchmarked through measurements of the Head-Tail mode zero instability. Since the SPS works above transition energy, the head tail mode zero is unstable for negative values of chromaticity. The measured instability growth rate is proportional to the real part of the transverse impedance. Studies performed after the LHC Injectors Upgrade (LIU) showed a relevant impedance around 2 GHz with high-gamma transition optics (Q26). This paper presents the follow-up studies to probe the behavior of this beam coupling impedance contribution.

Slides THAFP01 [2.262 MB]

Poster THAFP01 [1.149 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP01

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Received ※ 29 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 10 October 2023

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THAFP05

A Wireless Method for Beam Coupling Impedance Measurements of the LHC Goniometer

impedance, cavity, coupling, scattering

407

C. Antuono, C. Zannini
CERN, Meyrin, Switzerland
M. Migliorati, A. Mostacci
LNF-INFN, Frascati, Italy

The beam coupling impedance (BCI) of an accelerator component should be ideally evaluated exciting the device with the beam itself. However, this scenario is not always attainable and alternative methods must be exploited, such as the bench measurements techniques. The stretched Wire Method (WM) is a well established technique for BCI evaluations, although nowadays its limitations are well known. In particular, the stretched wire perturbs the electromagnetic boundary conditions. Therefore, the results obtained could be inaccurate, especially below the cut-off frequency of the beam pipe in the case of cavity-like structures. To overcome these limitations, efforts are being made to investigate alternative bench measurement techniques that will not require the modification of the device under test (DUT). In this framework, a wireless method has been identified and tested for a pillbox cavity. Its potential for more complex structures, such as the LHC crystal goniometer is explored.

Slides THAFP05 [1.088 MB]

Poster THAFP05 [1.151 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP05

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Received ※ 29 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 11 October 2023

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THAFP06

Beam Dynamics Study of a 400 kW D⁺ Linear Accelerator to Generate Fusion-Like Neutrons for Breeding Blanket Tests in Korea

linac, target, SRF, MEBT

411

Y.L. Cheon, M.Y. Ahn, S. Cho, H.W. Kim
KFE, Daejeon, Republic of Korea
M. Chung, E. Cosgun, D. Kwak, S.H. Moon
UNIST, Ulsan, Republic of Korea

Recently, a pre-conceptual design study was conducted in Korea for developing a dedicated linear accelerator (linac) for 400 kW (40 MeV, maximum 10 mA CW) deuteron (D⁺) beams to generate fusion-like neutrons*. The accelerated beam hits a solid Beryllium target to produce fusion-like neutrons, which will be utilized for technical feasibility tests of the breeding blanket including tritium production and recovery**. In this work, we present a detailed start-to-end simulation and machine imperfection studies with proper beam tuning, to access the target beam availability and validate the machine specifications. We have designed the 2.45 GHz ECR ion source and a 4-vane type 176 MHz RFQ by using IBSimu, Parmteq, and Toutatis simulation codes. We propose a super-conducting linac with HWR cavities and solenoid focusing magnets to accelerate the beam up to 40 MeV. In the HEBT line, we adopt two octupole magnets and subsequent quadrupoles to make a rectangular-shaped and uniform-density beam with 20 cm x 20 cm footprint at the target. Extensive beam dynamics studies along the linac have been performed using the Tracewin simulation code.
* Y-L. Cheon et al., Journal of the Korean Physical Society (2023): 1-14.
** S-H. Hong et al., Fusion Engineering and Design 189 (2023): 113449.

Slides THAFP06 [1.039 MB]

Poster THAFP06 [1.491 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP06

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Received ※ 26 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 21 October 2023

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THAFP09

Optimizing Beam Dynamics in LHC with Active Deep Learning

framework, network, dynamic-aperture, hadron

422

D. Di Croce, T. Pieloni, M. Seidel
EPFL, Lausanne, Switzerland
M. Giovannozzi, F.F. Van der Veken
CERN, Meyrin, Switzerland
E. Krymova
SDSC, Lausanne, Switzerland
M. Seidel
PSI, Villigen PSI, Switzerland

The Dynamic Aperture (DA) is an important concept for the study of non-linear beam dynamics in a circular accelerator. It refers to the region in phase space where a particle’s motion remains bounded over a given number of turns. Understanding the features of DA is crucial for operating circular accelerators as it provides insights on non-linear beam dynamics and the phenomena affecting beam lifetime. The standard approach to calculate the DA is computationally very intensive. In our study, we aim at determining an optimal set of parameters that affect DA, like betatron tune, chromaticity, and Landau octupole strengths, using a Deep Neural Network (DNN) model. The DNN model predicts the so-called angular DA, based on simulated LHC data. To enhance its performance, we integrated the DNN model into an innovative Active Learning (AL) framework. This framework not only enables retraining and updating of the model, but also facilitates efficient data generation through smart sampling. The results demonstrate that the use of the Active Learning (AL) framework allows faster scanning of LHC ring configuration parameters without compromising the accuracy of the DA calculations.

Slides THAFP09 [1.028 MB]

Poster THAFP09 [6.173 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP09

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Received ※ 01 October 2023 — Revised ※ 04 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 31 October 2023

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THBP03

ESS-Bilbao RFQ Static Tuning Algorithm and Simulation

rfq, cavity, operation, neutron

440

J.L. Muñoz, I. Bustinduy, A. Conde, N. Garmendia, P.J. González, J. Martin, V. Toyos
ESS Bilbao, Zamudio, Spain

The ESS-Bilbao RFQ operates at 352.2 MHz. The machining of the four RFQ segments has finished and the assembly and tuning operations will follow shorly. The static tuning and field flatness are provided by an array of 60 plunger tuners, distributed along the 3.2 meters length of the structure. There are four tuners per segment per quadrant, except for one of the segments where the ports are used by the power couplers. A bead-pull setup will provide the measurements of the field profiles, that will be collected in a matrix built up with the contributions of individual tuners. The conventional approach of inverting the matrix to get the optimum tuners distribution is explored, as well as additional optimization method. Particularly, a genetic optimization algorithm provides a very succesful tuning of the RFQ. The solution provided by this approach will be used as the initial configuration of the tuners before the bead-pull measurements are carried out. Additionally, static and dynamic tuning of the RFQ is studied by high performance computing simulations of the RFQ. The analysis of the in-house computational electromagnetics suite used for these tasks is also discussed in this paper.

Poster THBP03 [2.285 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP03

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Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 28 October 2023

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THBP06

RFQ Upgrades for IFMIF-DONES

rfq, emittance, neutron, toolkit

451

M. Comunian, L. Bellan, A. Palmieri, A. Pisent
INFN/LNL, Legnaro (PD), Italy

In the framework of IFMIF-DONES (International Fusion Materials Irradiation Facility- DEMO-Oriented Neutron Early Source) ¿ a powerful neutron irradiation facility for studies and certification of materials to be used in fusion reactors is planned as part of the European roadmap to fusion electricity. A possible RFQ upgrade has been designed. In this article the beam dynamics of an RFQ able to handle CW 200 mA of Deuterium, based on experience of IFMIF RFQ, will be presented.

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP06

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Received ※ 24 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 15 October 2023

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THBP10

A Linearized Vlasov Method for the Study of Transverse e-Cloud Instabilities

electron, quadrupole, dipole, betatron

462

S. Johannesson, M. Seidel
EPFL, Lausanne, Switzerland
G. Iadarola
CERN, Meyrin, Switzerland

Using a Vlasov approach, electron cloud driven instabilities can be modeled to study beam stability on time scales that conventional Particle In Cell simulation methods cannot access. The Vlasov approach uses a linear description of electron cloud forces that accounts for both the betatron tune modulation along the bunch and the dipolar kicks from the electron cloud. Forces from electron clouds formed in quadrupole magnets as well as dipole magnets have been expressed in this formalism. In addition, the Vlasov approach can take into account the effect of chromaticity. To benchmark the Vlasov approach, it was compared with macroparticle simulations using the same linear description of electron cloud forces. The results showed good agreement between the Vlasov approach and macroparticle simulations for strong electron clouds, with both approaches showing a stabilizing effect from positive chromaticity. This stabilizing effect is consistent with observations from the LHC.

Poster THBP10 [4.059 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP10

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Received ※ 26 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 14 October 2023

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THBP12

Slow vs Fast Landau Damping Threshold Measurement at the LHC and Implications for the HL-LHC

octupole, damping, experiment, emittance

470

X. Buffat, L. Giacomel, N. Mounet
CERN, Meyrin, Switzerland

The mechanism of Loss of Landau Damping by Diffusion (L2D2) was observed in dedicated experiments at the LHC using a controlled external source of noise. Nevertheless, the predictions of stability threshold by L2D2 models are plagued by the poor knowledge of the natural noise floor affecting the LHC beams. Experimental measurements of the stability threshold on slow and fast time scales are used to better constrain the model. The improved model is then used to quantify requirements in terms of Landau damping for the HL-LHC.

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP12

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Received ※ 29 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 30 October 2023

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THBP13

Recent Developments with the New Tools for Collimation Simulations in Xsuite

collimation, coupling, scattering, proton

474

F.F. Van der Veken, A. Abramov, G. Broggi, F. Cerutti, M. D’Andrea, D. Demetriadou, L.S. Esposito, G. Hugo, G. Iadarola, B. Lindström, S. Redaelli, V. Rodin, N. Triantafyllou
CERN, Meyrin, Switzerland

Simulations of single-particle tracking involving collimation systems need dedicated tools to perform the different tasks needed. These include the accurate description of particle-matter interactions when a tracked particle impacts a collimator jaw; a detailed aperture model to identify the longitudinal location of losses; and others. One such tool is the K2 code in SixTrack, which describes the scattering of high-energy protons in matter. This code has recently been ported into the Xsuite tracking code that is being developed at CERN. Another approach is to couple the tracking with existing tools, such as FLUKA or Geant4, that offer better descriptions of particle-matter interactions and can treat lepton and ion beams. This includes the generation of secondary particles and fragmentation when tracking ions. In addition to the development of coupling with Geant4, the SixTrack-FLUKA coupling has recently been translated and integrated into the Xsuite environment as well. In this paper, we present the ongoing development of these tools. A thorough testing of the new implementation was performed, using as case studies various collimation layout configurations for the LHC Run 3.

Poster THBP13 [2.785 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP13

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Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 13 October 2023 — Issued ※ 23 October 2023

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THBP16

Emittance Growth From Electron Clouds Forming in the LHC Arc Quadrupoles

emittance, resonance, optics, electron

487

K. Paraschou, H. Bartosik, L. Deniau, G. Iadarola, E.H. Maclean, L. Mether, Y. Papaphilippou, G. Rumolo, R. Tomás García
CERN, Meyrin, Switzerland
T. Pieloni, J.M.B. Potdevin
EPFL, Lausanne, Switzerland

Operation of the Large Hadron Collider with proton bunches spaced 25 ns apart favours the formation of electron clouds. In fact, a slow emittance growth is observed in proton bunches at injection energy (450 GeV), showing a bunch-by-bunch signature that is compatible with electron cloud effects. The study of these effects is particularly relevant in view of the planned HL-LHC upgrade, which relies on significantly increased beam intensity and brightness. Particle tracking simulations that take into account both electron cloud effects and the non-linear magnetic fields of the lattice suggest that the electron clouds forming in the arc quadrupoles are responsible for the observed degradation. In this work, the simulation results are studied to gain insight into the mechanism which drives the slow emittance growth. Finally, it is discussed how optimising the optics of the lattice can allow the mitigation of such effects.

Poster THBP16 [3.432 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP16

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Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 11 October 2023

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THBP17

Transverse Coherent Instability Studies for the High-Energy Part of the Muon Collider Complex

collider, impedance, cavity, synchrotron

491

D. Amorim, F. Batsch, L. Bottura, D. Calzolari, C. Carli, H. Damerau, A. Grudiev, A. Lechner, E. Métral, D. Schulte, K. Skoufaris
CERN, Geneva, Switzerland
A. Chancé
CEA-DRF-IRFU, France
T. Pieloni
EPFL, Lausanne, Switzerland

Funding: This project has received funding from the European Union¿s Research and Innovation programme under GA No 101094300 and the Swiss Accelerator Research and Technology (CHART) program (www.chart.ch).
The International Muon Collider Collaboration (IMCC) is studying a 3 TeV center-of-mass muon collider ring, as well as a possible next stage at 10 TeV. Muons being 200 times heavier than electrons, limitations from synchrotron radiation are mostly suppressed, but the muon decay drives the accelerator chain design. After the muon and anti-muon bunches are produced and 6D cooled, a series of Linac, recirculating Linac and Rapid Cycling Synchrotron (RCS) quickly accelerate the bunches before the collider ring. A large number of RF cavities are required in the RCS to ensure that over 90% of the muons survive in each ring. The effects of cavities higher-order modes on transverse coherent stability have been looked at in detail, including the one of a bunch offset in the cavities, along with possible mitigation measures. In the collider ring, the decay of high-energy muons is a challenge for heat load management and radiation shielding. A tungsten liner would protect the superconducting magnet from decay products. Impedance and related beam stability have been investigated to identify the minimum vacuum chamber radius and transverse damper properties required for stable beams.

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP17

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Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 01 November 2023

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THBP29

Effects of Cavity Pre-Detuning on RF Power Transients at Injection into the LHC

cavity, injection, operation, controls

530

B.E. Karlsen-Bæck, T. Argyropoulos, A.C. Butterworth, R. Calaga, I. Karpov, H. Timko, M. Zampetakis
CERN, Meyrin, Switzerland

At injection into the LHC, the RF system is perturbed by beam-induced voltage resulting in strong RF power transients and the instant detuning of the cavities. The automatic tuning system, however, needs time for the mechanical compensation of the resonance frequency to take place. Acting back on the beam, the transients in RF power are expected to limit the maximum injected intensity by generating unacceptable beam loss. Reducing them is therefore essential to reach the target intensity during the High Luminosity (HL) LHC era. At LHC flat bottom, the cavities are operated using the half-detuning beam-loading compensation scheme. As implemented today, the tuner control algorithm starts acting only after the injection of the first longer bunch train which causes the bunches for this injection to experience the largest power spikes. This contribution presents an adapted detuning scheme for the RF cavities before injection. It was proposed as a path to decrease the transients, hence increasing the available intensity margin for the available RF power. The expected gain is evaluated in particle tracking simulations and measurements acquired during operation.

Poster THBP29 [3.711 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP29

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Received ※ 30 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 22 October 2023

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THBP31

Electron Cloud Effects in the CERN Accelerators in Run 3

electron, operation, injection, kicker

538

L. Mether, H. Bartosik, L. Giacomel, G. Iadarola, S. Johannesson, I. Mases Solé, K. Paraschou, G. Rumolo, L. Sabato, C. Zannini, E. de la Fuente
CERN, Meyrin, Switzerland
S. Johannesson
EPFL, Lausanne, Switzerland

Several of the machines in the CERN accelerator complex, in particular the Large Hadron Collider (LHC) and the Super Proton Synchrotron (SPS), are prone to the build-up of electron clouds. Electron cloud effects are observed especially when the machines are operated with a 25 ns bunch spacing, which has routinely been used in the LHC since the start of its second operational run in 2015. After the completion of the LHC Injectors Upgrade program during the latest long shutdown period, the machines are currently operated with unprecedented bunch intensity and beam brightness. With the increase in bunch intensity, electron cloud effects have become one of the main performance limitations, as predicted by simulation studies. In this contribution we present the experimental observations of electron cloud effects since 2021 and discuss their implications for the future operation of the complex.

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP31

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Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 23 October 2023

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THBP32

Xobjects and Xdeps: Low-Level Libraries Empowering Beam Dynamics Simulations

GPU, target, interface, lattice

543

S. Łopaciuk, R. De Maria, G. Iadarola
CERN, Meyrin, Switzerland

Xobjects and Xdeps are Python libraries included in the Xsuite beam dynamics simulation software package. These libraries are crucial to achieving two of the main goals of Xsuite: speed and ease of use. Xobjects allows users to run simulations on various hardware in a platform-agnostic way: with little user intervention single- and multi-threading is supported as well as GPU computations using both CUDA and OpenCL. Xdeps provides support for deferred expressions in Xsuite. Relations among simulation parameters and functions driving properties of lattice elements can be defined or indeed imported from other tools such as MAD-X and then easily updated before or during the simulation.

Poster THBP32 [0.266 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP32

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Received ※ 21 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 17 October 2023

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THBP34

PSI Injector II and the 72 MeV Transfer Line: MinT-Simulation vs. Measurements

cyclotron, emittance, space-charge, extraction

547

C. Baumgarten, H. Zhang
PSI, Villigen PSI, Switzerland

PSI’s Injector II cyclotron is the only cyclotron worldwide that makes use of the so-called "Vortex effect", in which strong space charge forces generate the counter-intuitive effect to "roll up" bunches thus keeping them longitudinally compact. The effect has been verified by bunch shape measurements and the PIC-code OPAL. However, PSI’s new fast matrix code MinT allows to reproduce the Vortex effect by a linear matrix model which is computational much cheaper than PIC simulations, and is suitable for "online use" in Control rooms. Furthermore it provides the second moments of matched distributions.

Poster THBP34 [0.840 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP34

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Received ※ 30 September 2023 — Revised ※ 03 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 31 October 2023

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THBP35

Analysis Tools for Numerical Simulations of Dynamic Aperture with Xsuite

collider, dynamic-aperture, hadron, framework

551

T. Pugnat, M. Giovannozzi, F.F. Van der Veken
CERN, Meyrin, Switzerland
D. Di Croce
EPFL, Lausanne, Switzerland

Recently, several efforts have been made at CERN to develop a new tracking tool, Xsuite, which is intended to be the successor to SixTrack. In this framework, analysis tools have also been prepared with the goal of providing advanced post-processing techniques for the interpretation of dynamic aperture simulations. The proposed software suite, named Xdyna, is meant to be a successor to the existing SixDesk environment. It incorporates all recent approaches developed to determine the dynamic aperture for a fixed number of turns. It also enables studying the time evolution of the dynamic aperture and the fitting of rigorous models based on the stability-time estimate provided by the Nekhoroshev theorem. These models make it possible to link the dynamic aperture to beam lifetime, and thus provide very relevant information for the actual performance of particle colliders. These tools have been applied to studies related to the luminosity upgrade of the CERN Large Hadron Collider (HL-LHC), the results of which are presented here.

Poster THBP35 [0.514 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP35

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Received ※ 28 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 11 October 2023

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THBP36

Study of the Performance of the CERN Proton Synchrotron Internal Dump

beam-losses, proton, vacuum, synchrotron

555

T. Pugnat, L.S. Esposito, M. Giovannozzi, C. Hernalsteens, A. Huschauer, S. Niang
CERN, Meyrin, Switzerland
D. Domange, E. Gnacadja, R. Tesse
ULB, Bruxelles, Belgium

In the framework of the LHC Injector Upgrade project, a new internal dump for the CERN Proton Synchrotron (PS) has been designed, installed, and successfully commissioned. This device is meant to move rapidly into the beam and stop charged particles over several turns to provide protection to the PS hardware against beam-induced damage. The performance of the dump should ensure efficient use throughout the PS energy range, i.e. from injection at 2 GeV (kinetic energy) to flat top at 26 GeV (total energy). In this paper, detailed numerical simulations are presented, carried out with a combination of sophisticated beam dynamics and beam-matter interaction codes, assessing the behaviour of stopped or scattered particles. The results of these numerical simulations are compared with the data collected during the routine operation of the PS and its internal dump.

Poster THBP36 [0.609 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP36

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Received ※ 26 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 28 October 2023

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THBP37

Refining the LHC Longitudinal Impedance Model

impedance, cavity, injection, damping

559

M. Zampetakis, T. Argyropoulos, Y. Brischetto, R. Calaga, L. Giacomel, B.E. Karlsen-Bæck, I. Karpov, I. Karpov, N. Mounet, B. Salvant, H. Timko
CERN, GENEVA, Switzerland
B.E. Karlsen-Bæck
INFN-Roma, Roma, Italy

Modelling the longitudinal impedance for the Large Hadron Collider (LHC) has been a long-standing effort, especially in view of its High-Luminosity (HL) upgrade. The resulting impedance model is an essential input for beam dynamics studies. Increased beam intensities in the HL-LHC era will pose new challenges like RF power limitations, beam losses at injection and coupled-bunch instabilities throughout the acceleration cycle. Starting from the existing longitudinal impedance model, effort has been made to identify the main contributing devices and improve their modelling. Loss of Landau damping (LLD) simulations are performed to investigate the dependence of the stability threshold on the completeness of the impedance model and its broad-band cut-off frequency. Plans to perform beam measurements to estimate the cut-off frequency, by investigating the LLD threshold in operation, are also discussed.

Poster THBP37 [5.606 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP37

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Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 14 October 2023

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THBP45

Longitudinal Collective Effects at Beam Transfer from PS to SPS at CERN

beam-loading, impedance, injection, cavity

587

A. Lasheen, H. Damerau, I. Karpov, G. Papotti, E.T. Vinten
CERN, Meyrin, Switzerland

The hardware upgrades of the LHC Injectors Upgrade (LIU) project at CERN were completed during the Long Shutdown 2 (2019-2021) to prepare the injectors for the beams required by the High Luminosity (HL) LHC. Doubling the bunch intensity leads to new challenges due to collective effects. Although many bottlenecks were already solved, a remaining limitation is the important loss of particles at transfer from the Proton Synchrotron (PS) to the Super Proton Synchrotron (SPS). The maximum transmission achieved since the restart in 2021 is in the order of 90%, yet leading to unnecessary activation of the SPS. The losses are distributed at various instants of the SPS cycle: fast intensity decay right after injection, slow losses along the injection plateau while waiting for multiple injections from the PS, and uncaptured beam removed at start of acceleration. In this contribution, the focus is on longitudinal aspects of transfer losses and more specifically on intensity effects during the non-adiabatic bunch shorting performed in the PS prior to extraction, as well as on the longitudinal mismatch at injection due to misaligned bunch phases in the SPS caused by transient beam loading.

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP45

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Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 15 October 2023

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THBP46

Simulation of the ESS Proton Beam Window Scattering

target, scattering, proton, ion-source

591

E.D. Fackelman, E. Adli, H.E. Gjersdal, K.N. Sjobak
University of Oslo, Oslo, Norway
Y. Levinsen, A. Takibayev, C.A. Thomas
ESS, Lund, Sweden

The European Spallation Source produces neutrons used for science by delivering a 5MW proton beam to a tungsten target. The proton beam parameters must remain within a well-defined range during all phases of facility exploitation. The proton beam parameters are measured and monitored by an instrumentation suite, among which are two beam imaging systems. Parameters such as position and beam current density can be calculated from the images, supporting beam tuning and operation. However, one of the two systems may be affected by beam scattering. In this paper, we will focus on modelling the impact of the scattering on the beam on target distribution. The modelling process, involving simulation codes such as Geant4 and two-dimensional convolution in Matlab, is described. Initially, Geant4 simulates a scattered pencil beam. The resulting distribution is fitted and can be used similarly to an instrument response in image processing to model any possible beam distribution. Finally, we discuss the results of the scattered beam imaging model, showing the range of applications of the model and the impact of scattering on the beam parameters.

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP46

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Received ※ 01 October 2023 — Revised ※ 09 October 2023 — Accepted ※ 14 October 2023 — Issued ※ 21 October 2023

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THBP47

Studies on the Effect of Beam-Coupling Impedance on Schottky Spectra of Bunched Beams

impedance, synchrotron, coupling, diagnostics

595

C. Lannoy, D. Alves, K. Łasocha, N. Mounet
CERN, Meyrin, Switzerland
C. Lannoy, T. Pieloni
EPFL, Lausanne, Switzerland

Schottky monitors can be used for non-invasive beam diagnostics to estimate various bunch characteristics, such as tune, chromaticity, bunch profile or synchrotron frequency distribution. However, collective effects, in particular beam-coupling impedance, can significantly affect Schottky spectra when large bunch charges are involved. In such conditions, the available interpretation methods are difficult to apply directly to the measured spectra, thus preventing the extraction of beam and machine parameters, which is possible for lower bunch charges. To study the impact of impedance on such spectra, we perform here time-domain, macro-particle simulations and apply a semi-analytical method to compute the Schottky signal for various machine and beam conditions, including those corresponding to typical physics operation at the Large Hadron Collider. This study provides preliminary interpretations of the impact of beam-coupling impedance on Schottky spectra by incorporating longitudinal and transverse resonator-like impedance models into the simulations.

Poster THBP47 [1.133 MB]

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reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP47

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Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 21 October 2023

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THBP59

Tomographic Longitudinal Phase Space Reconstruction of Bunch Compression at ISIS

synchrotron, proton, operation, extraction

625

B.S. Kyle, H.V. Cavanagh, A. Seville, R.E. Williamson
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

ISIS is an 800 MeV, high intensity, rapid-cycling synchrotron (RCS) used as a driver for a spallation neutron and muon spectroscopy (¿SR) facility. The intensity-limited beam and RCS operation at ISIS poses significant challenges, with non-adiabatic acceleration and space charge forces resulting in distortions to the Hamiltonian longitudinal dynamics. Effective modelling of the machine and benchmarking of models with beam measurements is essential both to improving machine performance, and to the development of the proposed ISIS II facility. The tomographic principle is a well-established tool for the reconstruction of the longitudinal phase space (LPS) of synchrotron beams. Is it operationally desirable for the ISIS accelerator to provide longitudinally compressed proton beams for ¿SR instrumentation. A new bunch compression scheme has been developed and validated using tomography. A reconstruction of the LPS of the ISIS high-intensity proton beam is presented, along with accompanying benchmarking measurements and beam physics simulations.

Poster THBP59 [0.907 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP59

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Received ※ 01 October 2023 — Revised ※ 09 October 2023 — Accepted ※ 20 October 2023 — Issued ※ 25 October 2023

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FRA2I1

Summary of the Working Group A: Beam Dynamics in Rings

space-charge, resonance, experiment, impedance

662

H. Bartosik, G. Rumolo
CERN, Meyrin, Switzerland
J.-L. Vay
LBNL, Berkeley, California, USA
N. Wang
IHEP, Beijing, People’s Republic of China

The HB-2023 workshop at CERN from October 9 to 13, 2023 is the continuation of the series of workshops, which started in 2002 at FNAL and rotates every two years between America, Europe and Asia. This contribution summarises the main highlights from Working Group A, Beam Dynamics in Rings, in terms of progress and challenges in the achievement of ever higher intensity and brightness hadron beams in accelerator rings around the world.

Slides FRA2I1 [4.325 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-FRA2I1

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Received ※ 04 December 2023 — Accepted ※ 05 December 2023 — Issued ※ 01 January 2024

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FRA2I2

Summary of the Working Group B

linac, space-charge, rfq, operation

666

N.J. Evans
ORNL RAD, Oak Ridge, Tennessee, USA
F. Bouly
LPSC, Grenoble Cedex, France
H.W. Zhao
IMP/CAS, Lanzhou, People’s Republic of China

Summary of the Working Group on Beam Dynamics in Linacs.

Slides FRA2I2 [1.306 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-FRA2I2

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Received ※ 23 November 2023 — Accepted ※ 29 November 2023 — Issued ※ 24 January 2024

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FRA2I5

Summary of Working Group E: Instrumentation and Intercepting Devices

target, radiation, instrumentation, operation

677

P. Forck
GSI, Darmstadt, Germany
P. Hurh
Fermilab, Batavia, Illinois, USA
K. Satou
KEK, Tokai, Ibaraki, Japan

The talk concerns the summary of the Working Group E related to Instrumentation and Intercepting Devices

Slides FRA2I5 [6.640 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-FRA2I5

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Received ※ 26 November 2023 — Accepted ※ 29 November 2023 — Issued ※ 13 January 2024

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