HB2023 - List of Keywords (space-charge)

Paper	Title	Other Keywords	Page
MOA1I3	Intense Beam Issues in CSNS Accelerator Beam Commissioning	MMI, sextupole, injection, cavity	16
	L. Huang, H.Y. Liu, X.H. Lu, X.B. Luo, J. Peng, L. Rao IHEP CSNS, Guangdong Province, People’s Republic of China Y.W. An, J. Chen, M.Y. Huang, Y. Li, Z.P. Li, S. Wang IHEP, Beijing, People’s Republic of China S.Y. Xu DNSC, Dongguan, People’s Republic of China
	The China Spallation Neutron Source (CSNS) consists of an 80 MeV H⁻ Linac, a 1.6 GeV Rapid Cycling Synchrotron (RCS), beam transport lines, a target station, and three spectrometers. The CSNS design beam power is 100 kW, with the capability to upgrade to 500 kW. In August 2018, CSNS was officially opened to domestic and international users. By February 2020, the beam power had reached 100 kW, and through improvements such as adding harmonic cavities, the beam power was increased to 140 kW. During the beam commissioning process, the beam loss caused by space charge effects was the most significant factor limiting the increase in beam power. Additionally, unexpected collective effects were observed, including coherent oscillations of the bunches, after the beam power reached 50 kW. Through a series of measures, the space charge effects and collective instabilities causing beam loss were effectively controlled. This paper mainly introduces the strong beam effects discovered during the beam commissioning at CSNS and their suppression methods. It also briefly discusses the research on beam space charge effects and collective effects in the beam dynamics design of CSNS-II project.
	Slides MOA1I3 [8.597 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-MOA1I3
About •	Received ※ 01 October 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 24 October 2023
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TUA2I1	Xsuite: An Integrated Beam Physics Simulation Framework	simulation, optics, 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	simulation, 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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TUC2C2	Evaluating PyORBIT as Unified Simulation Tool for Beam-Dynamics Modeling of the ESS Linac	lattice, simulation, DTL, EPICS	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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TUC3I1	Ultra-low Emittance Bunches from Laser Cooled Ion Traps for Intense Focal Points	emittance, laser, luminosity, ECR	128
	S.J. Brooks BNL, Upton, New York, USA
	Laser-cooled ion traps are used to prepare groups of ions in very low temperature states, exhibiting such phenomena as Coulomb crystallization. This corresponds to very small normalized RMS emittances of 10^-13–10^-12 m, compared to typical accelerator ion sources in the 10^-7–10^-6 m range. Such bunches could potentially be focused a million times smaller, compensating for the lower number of ions per bunch. Such an ultra-low emittance source could enable high-specific-luminosity colliders where reduced beam current and apertures are needed to produce a given luminosity. Further advances needed to enable such colliders include linear, helical or ring cooling channel designs for increased bunch number or current throughput. Novel high density focal points using only a single bunch also appear possible, where the high density particles collide with themselves. At collider energies ~100 GeV, these approach the nuclear density and offer a way of studying larger quantities of neutron star matter and other custom nuclear matter in the lab.
	Slides TUC3I1 [167.328 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC3I1
About •	Received ※ 26 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 24 October 2023
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WEA1I2	Analytical and Numerical Studies on Kicked Beams in the Context of Half-Integer Studies	resonance, coupling, emittance, damping	188
	G. Franchetti GSI, Darmstadt, Germany F. Asvesta, H. Bartosik, T. Prebibaj CERN, Meyrin, Switzerland
	In the context of the half-integer studies an investigation of the dynamics of the kicked beam has revealed surprising properties. The coupling of space charge with chromatic- ity in addition to usual damping/non-damping dynamics, exhibits new properties typical of a linear coupling. This proceeding covers the status of these studies carried out with analytical and numerical approaches and the prelimi- nary results of experimental investigations in the CERN PS Booster.
	Slides WEA1I2 [24.966 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA1I2
About •	Received ※ 02 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 13 October 2023 — Issued ※ 24 October 2023
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WEA2I1	Compensation of Third-order Resonances in the High Intensity Regime	resonance, sextupole, operation, experiment	215
	C.E. Gonzalez-Ortiz MSU, East Lansing, Michigan, USA R. Ainsworth Fermilab, Batavia, Illinois, USA P.N. Ostroumov FRIB, East Lansing, Michigan, USA
	As the Fermilab Accelerator Complex enters the high-intensity era, the Recycler Ring (RR) needs to mitigate the detrimental effect of third-order resonance crossing. Third-order resonance lines can be compensated to first order by cancelling out the global Resonance Driving Terms (RDTs) using the response matrix method. This compensation scheme has been proven to work at low intensities, i.e., in the single-particle regime. In order to evaluate the effectiveness of this compensation scheme at higher intensities, this study looks at dynamic and static tune scans, with and without resonance compensation, and different space charge tune shifts. Special care was taken in order to disentangle effects from space charge tune shift, structure resonances and space charge driven resonances.
	Slides WEA2I1 [6.714 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2I1
About •	Received ※ 02 October 2023 — Revised ※ 07 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, simulation, 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	resonance, acceleration, ECR, simulation	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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WEA2C2	Measurement of Transverse Statistical Dependence for Non-Gaussian Beam Distributions via Resonances in the CERN PSB	resonance, experiment, factory, luminosity	231
	E.R. Lamb, F. Asvesta, H. Bartosik, G. Sterbini CERN, Meyrin, Switzerland E.R. Lamb EPFL, Lausanne, Switzerland
	This work addresses the origins and the effects of the statistical dependence in non-Gaussian beam distributions with the ultimate goal to identify the most representative case for tracking simulations across the CERN accelerator complex. Starting from the observation that non-Gaussian heavy-tailed transverse beam profiles can be reconstructed from 4D phase space distributions under two different conditions (statistical independence or dependence in the x-y plane), we consider space charge dominated beams interacting with the lattice nonlinear resonances to perform measurements to study the mechanisms that lead to non-Gaussian distributions. Finally, we explore the beam dynamics implications of the above hypotheses in terms of dependent loss processes across the transverse planes.
	Slides WEA2C2 [1.249 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2C2
About •	Received ※ 30 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 21 October 2023
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WEA3C1	The Tracking Code RF-Track and Its Application	electron, simulation, linac, positron	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	linac, DTL, simulation, 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	simulation, 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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WEC3I1	Self-Consistent Injection Painting for Space Charge Mitigation	injection, emittance, solenoid, experiment	258
	N.J. Evans, V.S. Morozov ORNL RAD, Oak Ridge, Tennessee, USA T.V. Gorlov, A.M. Hoover ORNL, Oak Ridge, Tennessee, USA
	Funding: This work was conducted at UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy, with partial funding provided by Field Work Proposal ORNL-ERKCS41. I will present results of experiments at the Spallation Neutron Source to implement a method of phase space painting we refer to as ¿eigenpainting¿, in which beam is injected along one eigenvector of the transfer matrix of a ring with full coupling. The method and resultant distribution were initially proposed by Danilov almost to linearize the space charge force, minimizing space charge tune spread. In the theoretically ideal case this so-called Danilov distribution has uniform charge distribution, elliptical envelope in real-space, and a vanishing 4D transverse emittance. Such a beam can be maintained throughout injection. The Danilov distribution has implications for increasing beam intensity beyond the conventional space charge limit through a reduction of both tune spread and shift, and increasing collider performance. This talk will present current limits on beam quality, and details of the preparation of the optics in the SNS accumulator ring, including the installation of new solenoid magnets. The status of experiments to improve beam quality and characterize the interesting dynamical implications of the defining features of the Danilov distribution will also be discussed.
	Slides WEC3I1 [2.687 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC3I1
About •	Received ※ 28 September 2023 — Revised ※ 10 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 23 October 2023
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WEC3I2	Mitigation of Space Charge Effects in RHIC and Its Injectors	booster, emittance, injection, polarization	264
	V. Schoefer, C.J. Gardner, K. Hock, H. Huang, K. Zeno BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy The RHIC collider physics program, in particular its polarized proton and low energy heavy ion components, present unique challenges for maintaining collider performance in the presence of space charge effects. Polarized beam performance is especially sensitive to emittance increases, since they decrease both the luminosity and polarization. Operation of the collider with gold beams at sub-injection energies (down to 3.85 GeV/n Au) with space charge tune shifts up to 0.1 required special care to optimize both the ion lifetime and its interaction with the electron-beam cooler. We describe the operational experience in these modes and some of the mitigation efforts.
	Slides WEC3I2 [10.503 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC3I2
About •	Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 14 October 2023
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THA1I2	High-Intensity Studies on the ISIS RCS and Their Impact on the Design of ISIS-II	simulation, 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, emittance, simulation, 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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THA2C3	Periodic Solution for Transport of Intense and Coupled Coasting Beams Through Quadrupole Channels	solenoid, coupling, lattice, quadrupole	372
	C. Xiao, L. Groening GSI, Darmstadt, Germany
	Imposing defined spinning to a particle beam increases its stability against perturbations from space charge [Y.-L. Cheon et al., Effects of beam spinning on the fourth-order particle resonance of 3D bunched beams in high intensity linear accelerators, Phys. Rev. Accel. & Beams 25, 064002 (2022)]. In order to fully explore this potential, proper matching of intense coupled beams along regular lattices is mandatory. Herein, a novel procedure assuming matched transport is described and bench-marked through simulations. The concept of matched transport along periodic lattices has been extended from uncoupled beams to those with considerable coupling between the two transverse degrees of freedom. For coupled beams, matching means extension of cell-to-cell periodicity from just transverse envelopes to the coupled beam moments and to quantities being derived from these.
	Slides THA2C3 [1.649 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THA2C3
About •	Received ※ 25 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 19 October 2023
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THAFP04	Investigation of Tail-dominated Instability in the Fermilab Recycler Ring	operation, diagnostics, emittance, coupling	403
	O. Mohsen, R. Ainsworth, A.V. Burov Fermilab, Batavia, Illinois, USA
	In our recent operational run, a single bunch, tail-dominated instability was observed in the Fermilab Recycler ring. This instability exclusively occurs in the vertical plane when the chromaticity is close to zero. In this study, we conduct a detailed analysis of this instability under different operational parameters. We investigate the impact of space charge on the head-tail motion and propose potential interpretations of the underlying mechanism of the instability. Moreover, we explore methods to mitigate this instability in the future.
	Slides THAFP04 [1.429 MB]
	Poster THAFP04 [0.892 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP04
About •	Received ※ 25 September 2023 — Revised ※ 09 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 29 October 2023
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THBP08	Simulation Studies on the Low Energy Beam Transfer (LEBT) System of the ISIS Neutron Spallation Source	ion-source, rfq, LEBT, solenoid	454
	S.A. Ahmadiannamin, D.C. Faircloth, S.R. Lawrie, A.P. Letchford, T.M. Sarmento, O.A. Tarvainen STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The transmission efficiency and beam dynamic parameters of the low-energy beam transfer (LEBT) section of proton accelerators, serving as a neutron spallation source, have a critical impact on beam loss in subsequent sections of the linear accelerator. Due to variations and mismatches, the beam parameters at the entrance of the radio-frequency quadrupole (RFQ) change, significantly affecting the transmission efficiency of the RFQ and the matching between RFQ and drift tube linac (DTL) structures. Recognizing the importance of this concept, particle-in-cell studies were conducted to optimize the LEBT section of the ISIS accelerator. This study presents the results of simulations.
	Poster THBP08 [1.081 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP08
About •	Received ※ 01 October 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 30 October 2023
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THBP09	Pushing High Intensity and High Brightness Limits in the CERN PSB after the LIU Upgrades	resonance, brightness, injection, emittance	458
	F. Asvesta, S.C.P. Albright, H. Bartosik, C. Bracco, G.P. Di Giovanni, T. Prebibaj CERN, Meyrin, Switzerland
	After the successful completion of the LHC Injectors Upgrade (LIU) project, the CERN Proton Synchrotron Booster (PSB) has produced beams with up to two times higher brightness. However, the efforts to continuously improve the beam quality for the CERN physics experiments are ongoing. In particular, the high brightness LHC beams show non-Gaussian tails in the transverse profiles that can cause losses in the downstream machines, and even at LHC injection. As a result, alternative production schemes based on triple harmonic capture are being investigated in order to preserve brightness and reduce transverse tails at the same time. In addition, in view of a possible upgrade to the ISOLDE facility that would require approximately twice the number of protons per ring, the ultimate intensity reach of the PSB is explored. In this context, injection schemes using painting both transversely and longitudinally in order to mitigate the strong space charge effects are developed.
	Poster THBP09 [0.751 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP09
About •	Received ※ 28 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 20 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP19	Experimental Investigations on the High-Intensity Effects Near the Half-Integer Resonance in the PSB	resonance, experiment, emittance, brightness	499
	T. Prebibaj, F. Antoniou, F. Asvesta, H. Bartosik CERN, Meyrin, Switzerland G. Franchetti GSI, Darmstadt, Germany
	Space charge effects are the main limitation for the brightness performance of the Proton Synchrotron Booster (PSB) at CERN. Following the upgrades of the LHC Injectors Upgrade (LIU) project, the PSB delivered unprecedented brightness even exceeding the projected target parameters. A possibility for further increasing the brightness is to operate above the half-integer resonance 2Q_y=9 in order to avoid emittance blow-up from resonances at Q_x,y=4 due to the strong space charge detuning. The half-integer resonance can be compensated to a great extent using the available quadrupole correctors in the PSB, and also deliberately excited in a controlled way. The control of the half-integer resonance and the flexibility of the PSB to create a variety of different beam and machine conditions allowed the experimental characterization of space charge effects near this resonance. This contribution reports the experimental observations of the particle trapping during the dynamic crossing of the half-integer, as well as systematic studies of the beam degradation from space charge induced resonance crossing.
	Poster THBP19 [3.077 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP19
About •	Received ※ 30 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 23 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP23	Exploring Space Charge and Intra-beam Scattering Effects in the CERN Ion Injector Chain	emittance, scattering, injection, operation	515
	E. Waagaard EPFL, Lausanne, Switzerland H. Bartosik CERN, Meyrin, Switzerland
	As of today, the LHC ion physics programme is mostly based on Pb ion collisions. The ALICE3 detector proposal requests significantly higher nucleon-nucleon luminosities, as compared to today¿s operation. This improved performance could be potentially achieved with lighter ion species than Pb. In this respect, the CERN Ion Injector chain (consisting of Linac3, LEIR, PS and SPS) will need to provide significantly higher beam intensities with light ion beams as compared to the present ones, whereas operational experience with such beams is limited. We present space charge and intra-beam scattering studies across the Ion Injector chain and strategies to build benchmarked simulation models for optimised ion performance. This is the first step for identifying the ideal ion isotopes and charge states for maximised LHC luminosity production.
	Poster THBP23 [2.744 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP23
About •	Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 24 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP24	RCS and Accumulator Rings Designs for ISIS II	injection, proton, emittance, lattice	519
	D.J. Adams STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom H.V. Cavanagh, I.S.K. Gardner, B.S. Kyle, H. Rafique, C.M. Warsop, R.E. Williamson STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	ISIS is the spallation neutron source at the Rutherford Appleton Laboratory in the UK, which provides 0.2 MW of beam power via a 50 Hz, 800 MeV proton RCS. Detailed studies are now underway to find the optimal configuration for a next generation, short-pulsed neutron source that will define a major ISIS upgrade, with construction beginning ~2031. Determining the optimal specification for such a facility is the subject of an ongoing study involving neutron users, target and instrument experts. The accelerator designs being considered for the MW beam powers required, include proposals exploiting FFA rings as well as conventional accumulator and RCS rings. This paper summarises work on physics designs for the conventional rings. Details of lattice designs, injection and extraction systems, correction systems as well as detailed 3D PIC simulations used to ensure 0.1% losses and low foil hits are presented. Designs for a 0.4 to 1.2 GeV RCS and 1.2 GeV AR are outlined. Work on the next stages of the study are also summarised to benchmark and minimise predicted losses, and thus maximise the high intensity limit of designs.
	Poster THBP24 [3.231 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP24
About •	Received ※ 28 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 22 October 2023
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THBP27	Experimental Investigation of Nonlinear Integrable Optics in a Paul Trap	lattice, octupole, resonance, experiment	523
	J.A.D. Flowerdew University of Oxford, Oxford, United Kingdom D.J. Kelliher, S. Machida STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom S.L. Sheehy STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	Funding: Work supported by Royal Society grants Octupoles are often used to damp beam instabilities caused by space charge. However, in general the insertion of octupole magnets leads to a nonintegrable lattice which reduces the area of stable particle motion. One proposed solution to this problem is Quasi-Integrable Optics (QIO), where the octupoles are inserted between a specially designed lattice called a T-insert. An octupole with a strength that scales as 1/β³(s) is applied in the drift region to create a time-independent octupole field, leading to a lattice with an invariant Hamiltonian. This means that large tune spreads can be achieved without reducing the dynamic aperture. IBEX is a Paul trap which confines low energy ions with an RF voltage, simulating the transverse dynamics of an alternating gradient accelerator. IBEX has recently undergone an upgrade to allow for octupole fields to be created in the trap in addition to quadrupole focusing. We present our first experimental results from testing QIO with the IBEX trap. jake.flowerdew@physics.ox.ac.uk
	Poster THBP27 [4.163 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP27
About •	Received ※ 30 September 2023 — Revised ※ 09 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 31 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP34	PSI Injector II and the 72 MeV Transfer Line: MinT-Simulation vs. Measurements	cyclotron, emittance, simulation, 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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP42	Longitudinal Loss of Landau Damping in Double Harmonic RF Systems below Transition Energy	synchrotron, damping, impedance, proton	575
	L. Intelisano, H. Damerau, I. Karpov CERN, Meyrin, Switzerland
	Landau damping plays a crucial role in ensuring single-bunch stability in hadron synchrotrons. In the longitudinal plane, loss of Landau damping (LLD) occurs when a coherent mode of oscillation moves out of the incoherent synchrotron frequency band. The LLD threshold is studied for a purely inductive impedance below transition energy, specifically considering the common case of double harmonic RF systems operating in counter-phase at the bunch position. The additional focusing force due to beam-induced voltage distorts the potential well, ultimately collapsing the bucket. The limiting conditions for a binomial particle distribution are calculated. Furthermore, the contribution focuses on the configuration of the higher-harmonic RF system at four times the fundamental RF frequency operating in phase. In this case, the LLD threshold shows a non-monotonic behavior with a zero threshold where the derivative of the synchrotron frequency distribution is positive. The findings are obtained employing semi-analytical calculations using the MELODY code.
	Poster THBP42 [1.710 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP42
About •	Received ※ 30 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 14 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP44	ImpactX Modeling of Benchmark Tests for Space Charge Validation	focusing, emittance, cavity, proton	583
	C.E. Mitchell, M. Garten, A. Huebl, R. Lehé, J. Qiang, R.T. Sandberg, J.-L. Vay LBNL, Berkeley, California, USA
	The code ImpactX represents the next generation of the particle-in-cell code IMPACT-Z, featuring s-based symplectic tracking with 3D space charge, parallelism with GPU acceleration, adaptive mesh-refinement, and modernized language features. With such a code comes a renewed need for space charge validation using well-defined benchmarks. For this purpose, the code is continuously checked against a test suite of exactly-solvable problems. The suite includes field calculation tests, dynamical tests involving coasting or stationary beams, and beams matched to periodic focusing channels. To study the long-time multi-turn performance of the code in a more complex setting, we investigate problems involving high-intensity storage rings, such as the GSI benchmark problem for space charge induced trapping. Comparisons against existing codes are made where possible.
	Poster THBP44 [1.020 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP44
About •	Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 26 October 2023
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FRA1I2	Design and Beam Commissioning of Dual Harmonic RF System in CSNS RCS	cavity, injection, bunching, MMI	633
	H.Y. Liu, L. Huang IHEP CSNS, Guangdong Province, People’s Republic of China Y. Liu DNSC, Dongguan, People’s Republic of China S. Wang, S.Y. Xu IHEP, Beijing, People’s Republic of China
	The CSNS accelerator achieved an average beam power on target of 100 kW in February 2020 and subsequently increased it to 125 kW in March 2022. Building upon this success, CSNS plans to further enhance the average beam power to 200 kW by doubling the particle number of the circulating beam in the RCS, while keeping the injection energy same. The space charge effect is a main limit for the beam intensity increase in high-power particle accelerators. By providing a second harmonic RF cavity with a harmonic number of 4, in combination with the ferrite cavity with a harmonic number of 2, the dual harmonic RF system aims to mitigate emittance increase and beam loss caused by space charge effects, thereby optimizing the longitudinal beam distribution. This paper will concentrate on the beam commissioning for the 140 kW operation subsequent to the installation of the magnetic alloy (MA) cavity. The commissioning process includes the optimization of RF parameters, beam studies, and evaluation of the beam quality and instability.
	Slides FRA1I2 [4.086 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-FRA1I2
About •	Received ※ 30 September 2023 — Revised ※ 09 October 2023 — Accepted ※ 14 October 2023 — Issued ※ 27 October 2023
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FRA2I1	Summary of the Working Group A: Beam Dynamics in Rings	resonance, experiment, simulation, 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, rfq, operation, simulation	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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Paper

Title

Other Keywords

Page

MOA1I3

Intense Beam Issues in CSNS Accelerator Beam Commissioning

MMI, sextupole, injection, cavity

16

L. Huang, H.Y. Liu, X.H. Lu, X.B. Luo, J. Peng, L. Rao
IHEP CSNS, Guangdong Province, People’s Republic of China
Y.W. An, J. Chen, M.Y. Huang, Y. Li, Z.P. Li, S. Wang
IHEP, Beijing, People’s Republic of China
S.Y. Xu
DNSC, Dongguan, People’s Republic of China

The China Spallation Neutron Source (CSNS) consists of an 80 MeV H⁻ Linac, a 1.6 GeV Rapid Cycling Synchrotron (RCS), beam transport lines, a target station, and three spectrometers. The CSNS design beam power is 100 kW, with the capability to upgrade to 500 kW. In August 2018, CSNS was officially opened to domestic and international users. By February 2020, the beam power had reached 100 kW, and through improvements such as adding harmonic cavities, the beam power was increased to 140 kW. During the beam commissioning process, the beam loss caused by space charge effects was the most significant factor limiting the increase in beam power. Additionally, unexpected collective effects were observed, including coherent oscillations of the bunches, after the beam power reached 50 kW. Through a series of measures, the space charge effects and collective instabilities causing beam loss were effectively controlled. This paper mainly introduces the strong beam effects discovered during the beam commissioning at CSNS and their suppression methods. It also briefly discusses the research on beam space charge effects and collective effects in the beam dynamics design of CSNS-II project.

Slides MOA1I3 [8.597 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-MOA1I3

About •

Received ※ 01 October 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 24 October 2023

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TUA2I1

Xsuite: An Integrated Beam Physics Simulation Framework

simulation, optics, 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

simulation, 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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TUC2C2

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

lattice, simulation, DTL, EPICS

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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TUC3I1

Ultra-low Emittance Bunches from Laser Cooled Ion Traps for Intense Focal Points

emittance, laser, luminosity, ECR

128

S.J. Brooks
BNL, Upton, New York, USA

Laser-cooled ion traps are used to prepare groups of ions in very low temperature states, exhibiting such phenomena as Coulomb crystallization. This corresponds to very small normalized RMS emittances of 10^-13–10^-12 m, compared to typical accelerator ion sources in the 10^-7–10^-6 m range. Such bunches could potentially be focused a million times smaller, compensating for the lower number of ions per bunch. Such an ultra-low emittance source could enable high-specific-luminosity colliders where reduced beam current and apertures are needed to produce a given luminosity. Further advances needed to enable such colliders include linear, helical or ring cooling channel designs for increased bunch number or current throughput. Novel high density focal points using only a single bunch also appear possible, where the high density particles collide with themselves. At collider energies ~100 GeV, these approach the nuclear density and offer a way of studying larger quantities of neutron star matter and other custom nuclear matter in the lab.

Slides TUC3I1 [167.328 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC3I1

About •

Received ※ 26 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 24 October 2023

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WEA1I2

Analytical and Numerical Studies on Kicked Beams in the Context of Half-Integer Studies

resonance, coupling, emittance, damping

188

G. Franchetti
GSI, Darmstadt, Germany
F. Asvesta, H. Bartosik, T. Prebibaj
CERN, Meyrin, Switzerland

In the context of the half-integer studies an investigation of the dynamics of the kicked beam has revealed surprising properties. The coupling of space charge with chromatic- ity in addition to usual damping/non-damping dynamics, exhibits new properties typical of a linear coupling. This proceeding covers the status of these studies carried out with analytical and numerical approaches and the prelimi- nary results of experimental investigations in the CERN PS Booster.

Slides WEA1I2 [24.966 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA1I2

About •

Received ※ 02 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 13 October 2023 — Issued ※ 24 October 2023

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WEA2I1

Compensation of Third-order Resonances in the High Intensity Regime

resonance, sextupole, operation, experiment

215

C.E. Gonzalez-Ortiz
MSU, East Lansing, Michigan, USA
R. Ainsworth
Fermilab, Batavia, Illinois, USA
P.N. Ostroumov
FRIB, East Lansing, Michigan, USA

As the Fermilab Accelerator Complex enters the high-intensity era, the Recycler Ring (RR) needs to mitigate the detrimental effect of third-order resonance crossing. Third-order resonance lines can be compensated to first order by cancelling out the global Resonance Driving Terms (RDTs) using the response matrix method. This compensation scheme has been proven to work at low intensities, i.e., in the single-particle regime. In order to evaluate the effectiveness of this compensation scheme at higher intensities, this study looks at dynamic and static tune scans, with and without resonance compensation, and different space charge tune shifts. Special care was taken in order to disentangle effects from space charge tune shift, structure resonances and space charge driven resonances.

Slides WEA2I1 [6.714 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2I1

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Received ※ 02 October 2023 — Revised ※ 07 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, simulation, 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

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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

resonance, acceleration, ECR, simulation

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

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

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WEA2C2

Measurement of Transverse Statistical Dependence for Non-Gaussian Beam Distributions via Resonances in the CERN PSB

resonance, experiment, factory, luminosity

231

E.R. Lamb, F. Asvesta, H. Bartosik, G. Sterbini
CERN, Meyrin, Switzerland
E.R. Lamb
EPFL, Lausanne, Switzerland

This work addresses the origins and the effects of the statistical dependence in non-Gaussian beam distributions with the ultimate goal to identify the most representative case for tracking simulations across the CERN accelerator complex. Starting from the observation that non-Gaussian heavy-tailed transverse beam profiles can be reconstructed from 4D phase space distributions under two different conditions (statistical independence or dependence in the x-y plane), we consider space charge dominated beams interacting with the lattice nonlinear resonances to perform measurements to study the mechanisms that lead to non-Gaussian distributions. Finally, we explore the beam dynamics implications of the above hypotheses in terms of dependent loss processes across the transverse planes.

Slides WEA2C2 [1.249 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2C2

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Received ※ 30 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 21 October 2023

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WEA3C1

The Tracking Code RF-Track and Its Application

electron, simulation, linac, positron

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

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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

linac, DTL, simulation, 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

simulation, 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

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

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WEC3I1

Self-Consistent Injection Painting for Space Charge Mitigation

injection, emittance, solenoid, experiment

258

N.J. Evans, V.S. Morozov
ORNL RAD, Oak Ridge, Tennessee, USA
T.V. Gorlov, A.M. Hoover
ORNL, Oak Ridge, Tennessee, USA

Funding: This work was conducted at UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy, with partial funding provided by Field Work Proposal ORNL-ERKCS41.
I will present results of experiments at the Spallation Neutron Source to implement a method of phase space painting we refer to as ¿eigenpainting¿, in which beam is injected along one eigenvector of the transfer matrix of a ring with full coupling. The method and resultant distribution were initially proposed by Danilov almost to linearize the space charge force, minimizing space charge tune spread. In the theoretically ideal case this so-called Danilov distribution has uniform charge distribution, elliptical envelope in real-space, and a vanishing 4D transverse emittance. Such a beam can be maintained throughout injection. The Danilov distribution has implications for increasing beam intensity beyond the conventional space charge limit through a reduction of both tune spread and shift, and increasing collider performance. This talk will present current limits on beam quality, and details of the preparation of the optics in the SNS accumulator ring, including the installation of new solenoid magnets. The status of experiments to improve beam quality and characterize the interesting dynamical implications of the defining features of the Danilov distribution will also be discussed.

Slides WEC3I1 [2.687 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC3I1

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Received ※ 28 September 2023 — Revised ※ 10 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 23 October 2023

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WEC3I2

Mitigation of Space Charge Effects in RHIC and Its Injectors

booster, emittance, injection, polarization

264

V. Schoefer, C.J. Gardner, K. Hock, H. Huang, K. Zeno
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
The RHIC collider physics program, in particular its polarized proton and low energy heavy ion components, present unique challenges for maintaining collider performance in the presence of space charge effects. Polarized beam performance is especially sensitive to emittance increases, since they decrease both the luminosity and polarization. Operation of the collider with gold beams at sub-injection energies (down to 3.85 GeV/n Au) with space charge tune shifts up to 0.1 required special care to optimize both the ion lifetime and its interaction with the electron-beam cooler. We describe the operational experience in these modes and some of the mitigation efforts.

Slides WEC3I2 [10.503 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC3I2

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Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 14 October 2023

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THA1I2

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

simulation, 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, emittance, simulation, 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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THA2C3

Periodic Solution for Transport of Intense and Coupled Coasting Beams Through Quadrupole Channels

solenoid, coupling, lattice, quadrupole

372

C. Xiao, L. Groening
GSI, Darmstadt, Germany

Imposing defined spinning to a particle beam increases its stability against perturbations from space charge [Y.-L. Cheon et al., Effects of beam spinning on the fourth-order particle resonance of 3D bunched beams in high intensity linear accelerators, Phys. Rev. Accel. & Beams 25, 064002 (2022)]. In order to fully explore this potential, proper matching of intense coupled beams along regular lattices is mandatory. Herein, a novel procedure assuming matched transport is described and bench-marked through simulations. The concept of matched transport along periodic lattices has been extended from uncoupled beams to those with considerable coupling between the two transverse degrees of freedom. For coupled beams, matching means extension of cell-to-cell periodicity from just transverse envelopes to the coupled beam moments and to quantities being derived from these.

Slides THA2C3 [1.649 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THA2C3

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Received ※ 25 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 19 October 2023

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THAFP04

Investigation of Tail-dominated Instability in the Fermilab Recycler Ring

operation, diagnostics, emittance, coupling

403

O. Mohsen, R. Ainsworth, A.V. Burov
Fermilab, Batavia, Illinois, USA

In our recent operational run, a single bunch, tail-dominated instability was observed in the Fermilab Recycler ring. This instability exclusively occurs in the vertical plane when the chromaticity is close to zero. In this study, we conduct a detailed analysis of this instability under different operational parameters. We investigate the impact of space charge on the head-tail motion and propose potential interpretations of the underlying mechanism of the instability. Moreover, we explore methods to mitigate this instability in the future.

Slides THAFP04 [1.429 MB]

Poster THAFP04 [0.892 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP04

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Received ※ 25 September 2023 — Revised ※ 09 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 29 October 2023

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THBP08

Simulation Studies on the Low Energy Beam Transfer (LEBT) System of the ISIS Neutron Spallation Source

ion-source, rfq, LEBT, solenoid

454

S.A. Ahmadiannamin, D.C. Faircloth, S.R. Lawrie, A.P. Letchford, T.M. Sarmento, O.A. Tarvainen
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The transmission efficiency and beam dynamic parameters of the low-energy beam transfer (LEBT) section of proton accelerators, serving as a neutron spallation source, have a critical impact on beam loss in subsequent sections of the linear accelerator. Due to variations and mismatches, the beam parameters at the entrance of the radio-frequency quadrupole (RFQ) change, significantly affecting the transmission efficiency of the RFQ and the matching between RFQ and drift tube linac (DTL) structures. Recognizing the importance of this concept, particle-in-cell studies were conducted to optimize the LEBT section of the ISIS accelerator. This study presents the results of simulations.

Poster THBP08 [1.081 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP08

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Received ※ 01 October 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 30 October 2023

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THBP09

Pushing High Intensity and High Brightness Limits in the CERN PSB after the LIU Upgrades

resonance, brightness, injection, emittance

458

F. Asvesta, S.C.P. Albright, H. Bartosik, C. Bracco, G.P. Di Giovanni, T. Prebibaj
CERN, Meyrin, Switzerland

After the successful completion of the LHC Injectors Upgrade (LIU) project, the CERN Proton Synchrotron Booster (PSB) has produced beams with up to two times higher brightness. However, the efforts to continuously improve the beam quality for the CERN physics experiments are ongoing. In particular, the high brightness LHC beams show non-Gaussian tails in the transverse profiles that can cause losses in the downstream machines, and even at LHC injection. As a result, alternative production schemes based on triple harmonic capture are being investigated in order to preserve brightness and reduce transverse tails at the same time. In addition, in view of a possible upgrade to the ISOLDE facility that would require approximately twice the number of protons per ring, the ultimate intensity reach of the PSB is explored. In this context, injection schemes using painting both transversely and longitudinally in order to mitigate the strong space charge effects are developed.

Poster THBP09 [0.751 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP09

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Received ※ 28 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 20 October 2023

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THBP19

Experimental Investigations on the High-Intensity Effects Near the Half-Integer Resonance in the PSB

resonance, experiment, emittance, brightness

499

T. Prebibaj, F. Antoniou, F. Asvesta, H. Bartosik
CERN, Meyrin, Switzerland
G. Franchetti
GSI, Darmstadt, Germany

Space charge effects are the main limitation for the brightness performance of the Proton Synchrotron Booster (PSB) at CERN. Following the upgrades of the LHC Injectors Upgrade (LIU) project, the PSB delivered unprecedented brightness even exceeding the projected target parameters. A possibility for further increasing the brightness is to operate above the half-integer resonance 2Q_y=9 in order to avoid emittance blow-up from resonances at Q_x,y=4 due to the strong space charge detuning. The half-integer resonance can be compensated to a great extent using the available quadrupole correctors in the PSB, and also deliberately excited in a controlled way. The control of the half-integer resonance and the flexibility of the PSB to create a variety of different beam and machine conditions allowed the experimental characterization of space charge effects near this resonance. This contribution reports the experimental observations of the particle trapping during the dynamic crossing of the half-integer, as well as systematic studies of the beam degradation from space charge induced resonance crossing.

Poster THBP19 [3.077 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP19

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Received ※ 30 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 23 October 2023

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THBP23

Exploring Space Charge and Intra-beam Scattering Effects in the CERN Ion Injector Chain

emittance, scattering, injection, operation

515

E. Waagaard
EPFL, Lausanne, Switzerland
H. Bartosik
CERN, Meyrin, Switzerland

As of today, the LHC ion physics programme is mostly based on Pb ion collisions. The ALICE3 detector proposal requests significantly higher nucleon-nucleon luminosities, as compared to today¿s operation. This improved performance could be potentially achieved with lighter ion species than Pb. In this respect, the CERN Ion Injector chain (consisting of Linac3, LEIR, PS and SPS) will need to provide significantly higher beam intensities with light ion beams as compared to the present ones, whereas operational experience with such beams is limited. We present space charge and intra-beam scattering studies across the Ion Injector chain and strategies to build benchmarked simulation models for optimised ion performance. This is the first step for identifying the ideal ion isotopes and charge states for maximised LHC luminosity production.

Poster THBP23 [2.744 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP23

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Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 24 October 2023

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THBP24

RCS and Accumulator Rings Designs for ISIS II

injection, proton, emittance, lattice

519

D.J. Adams
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
H.V. Cavanagh, I.S.K. Gardner, B.S. Kyle, H. Rafique, C.M. Warsop, R.E. Williamson
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

ISIS is the spallation neutron source at the Rutherford Appleton Laboratory in the UK, which provides 0.2 MW of beam power via a 50 Hz, 800 MeV proton RCS. Detailed studies are now underway to find the optimal configuration for a next generation, short-pulsed neutron source that will define a major ISIS upgrade, with construction beginning ~2031. Determining the optimal specification for such a facility is the subject of an ongoing study involving neutron users, target and instrument experts. The accelerator designs being considered for the MW beam powers required, include proposals exploiting FFA rings as well as conventional accumulator and RCS rings. This paper summarises work on physics designs for the conventional rings. Details of lattice designs, injection and extraction systems, correction systems as well as detailed 3D PIC simulations used to ensure 0.1% losses and low foil hits are presented. Designs for a 0.4 to 1.2 GeV RCS and 1.2 GeV AR are outlined. Work on the next stages of the study are also summarised to benchmark and minimise predicted losses, and thus maximise the high intensity limit of designs.

Poster THBP24 [3.231 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP24

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Received ※ 28 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 22 October 2023

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THBP27

Experimental Investigation of Nonlinear Integrable Optics in a Paul Trap

lattice, octupole, resonance, experiment

523

J.A.D. Flowerdew
University of Oxford, Oxford, United Kingdom
D.J. Kelliher, S. Machida
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
S.L. Sheehy
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

Funding: Work supported by Royal Society grants
Octupoles are often used to damp beam instabilities caused by space charge. However, in general the insertion of octupole magnets leads to a nonintegrable lattice which reduces the area of stable particle motion. One proposed solution to this problem is Quasi-Integrable Optics (QIO), where the octupoles are inserted between a specially designed lattice called a T-insert. An octupole with a strength that scales as 1/β³(s) is applied in the drift region to create a time-independent octupole field, leading to a lattice with an invariant Hamiltonian. This means that large tune spreads can be achieved without reducing the dynamic aperture. IBEX is a Paul trap which confines low energy ions with an RF voltage, simulating the transverse dynamics of an alternating gradient accelerator. IBEX has recently undergone an upgrade to allow for octupole fields to be created in the trap in addition to quadrupole focusing. We present our first experimental results from testing QIO with the IBEX trap.
jake.flowerdew@physics.ox.ac.uk

Poster THBP27 [4.163 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP27

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Received ※ 30 September 2023 — Revised ※ 09 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 31 October 2023

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THBP34

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

cyclotron, emittance, simulation, 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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THBP42

Longitudinal Loss of Landau Damping in Double Harmonic RF Systems below Transition Energy

synchrotron, damping, impedance, proton

575

L. Intelisano, H. Damerau, I. Karpov
CERN, Meyrin, Switzerland

Landau damping plays a crucial role in ensuring single-bunch stability in hadron synchrotrons. In the longitudinal plane, loss of Landau damping (LLD) occurs when a coherent mode of oscillation moves out of the incoherent synchrotron frequency band. The LLD threshold is studied for a purely inductive impedance below transition energy, specifically considering the common case of double harmonic RF systems operating in counter-phase at the bunch position. The additional focusing force due to beam-induced voltage distorts the potential well, ultimately collapsing the bucket. The limiting conditions for a binomial particle distribution are calculated. Furthermore, the contribution focuses on the configuration of the higher-harmonic RF system at four times the fundamental RF frequency operating in phase. In this case, the LLD threshold shows a non-monotonic behavior with a zero threshold where the derivative of the synchrotron frequency distribution is positive. The findings are obtained employing semi-analytical calculations using the MELODY code.

Poster THBP42 [1.710 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP42

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Received ※ 30 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 14 October 2023

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THBP44

ImpactX Modeling of Benchmark Tests for Space Charge Validation

focusing, emittance, cavity, proton

583

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

The code ImpactX represents the next generation of the particle-in-cell code IMPACT-Z, featuring s-based symplectic tracking with 3D space charge, parallelism with GPU acceleration, adaptive mesh-refinement, and modernized language features. With such a code comes a renewed need for space charge validation using well-defined benchmarks. For this purpose, the code is continuously checked against a test suite of exactly-solvable problems. The suite includes field calculation tests, dynamical tests involving coasting or stationary beams, and beams matched to periodic focusing channels. To study the long-time multi-turn performance of the code in a more complex setting, we investigate problems involving high-intensity storage rings, such as the GSI benchmark problem for space charge induced trapping. Comparisons against existing codes are made where possible.

Poster THBP44 [1.020 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP44

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Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 26 October 2023

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FRA1I2

Design and Beam Commissioning of Dual Harmonic RF System in CSNS RCS

cavity, injection, bunching, MMI

633

H.Y. Liu, L. Huang
IHEP CSNS, Guangdong Province, People’s Republic of China
Y. Liu
DNSC, Dongguan, People’s Republic of China
S. Wang, S.Y. Xu
IHEP, Beijing, People’s Republic of China

The CSNS accelerator achieved an average beam power on target of 100 kW in February 2020 and subsequently increased it to 125 kW in March 2022. Building upon this success, CSNS plans to further enhance the average beam power to 200 kW by doubling the particle number of the circulating beam in the RCS, while keeping the injection energy same. The space charge effect is a main limit for the beam intensity increase in high-power particle accelerators. By providing a second harmonic RF cavity with a harmonic number of 4, in combination with the ferrite cavity with a harmonic number of 2, the dual harmonic RF system aims to mitigate emittance increase and beam loss caused by space charge effects, thereby optimizing the longitudinal beam distribution. This paper will concentrate on the beam commissioning for the 140 kW operation subsequent to the installation of the magnetic alloy (MA) cavity. The commissioning process includes the optimization of RF parameters, beam studies, and evaluation of the beam quality and instability.

Slides FRA1I2 [4.086 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-FRA1I2

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Received ※ 30 September 2023 — Revised ※ 09 October 2023 — Accepted ※ 14 October 2023 — Issued ※ 27 October 2023

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FRA2I1

Summary of the Working Group A: Beam Dynamics in Rings

resonance, experiment, simulation, 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, rfq, operation, simulation

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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