HB2023 - Classification: Beam Dynamics in Linacs

Paper	Title	Page
MOA2I3	Accelerator Challenges at ESS
	M.E. Eshraqi ESS, Lund, Sweden
	The European Spallation Source (ESS), undergoing concurrent installation, testing and beam commissioning in Lund, Sweden, will be the brightest source of cold neutrons once the driving proton linac reaches the intermediate energy of 800 MeV and a power of 2 MW. The final goal of ESS is to deliver a 2 GeV beam of protons with an average power of 5 MW to target. The high brightness of the neutron source is achieved by optimization of the rotating tungsten target and the innovative butterfly neutron moderator. The high beam power of the linac demands high-quality beam production, efficient acceleration, and near lossless transport of a high current beam. All of these impose strict requirements on the design and beam commissioning of this machine. The linac is being commissioned in several steps as the installation progresses. This talk presents the status of the project, challenges in the accelerator and updates on the beam commissioning.
	Slides MOA2I3 [19.436 MB]
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUC1I1	Multi-beam Operation of LANSCE Accelerator Facility	58
	Y.K. Batygin LANL, Los Alamos, New Mexico, USA
	The unique feature of the LANSCE accelerator facility is the simultaneous delivering of beams to five experimental targets. Proton beam with energy of 100-MeV is delivered to Isotope Production Facility (IPF), while 800-MeV H⁻ beams are distributed to four experimental areas: the Lujan Neutron Scattering Center, the Weapons Neutron Research facility (WNR), the Proton Radiography facility (pRad), and the Ultra-Cold Neutron facility (UCN). Multi-beam operation of accelerator facility requires careful optimization of beam losses, which is achieved by precise tuning of the beam, imposing restriction on amplitudes and phases of RF sections, application of beam-based alignment, control of H⁻ beam stripping, optimization of ion sources performance and low-energy beam transport operation under space-charge neutralization. The near - term plans are to replace obsolete systems of the LANSCE linear accelerator with modern Front End, which is the part of Los Alamos Modernization Project (LAMP). This paper summarizes experimental results obtained during operation of LANSCE accelerator facility and considers plans to expand performance of the accelerator for near-and long-term operations.
	Slides TUC1I1 [10.013 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC1I1
About •	Received ※ 30 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 31 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUC1I2	30 kW Beam Commissioning of the High-Intensity Proton Accelerator IPHI: Experiments, Simulations and Space Charge
	N. Chauvin, B. Bolzon, A.C. Chauveau, D. Chirpaz, M.J. Desmons, A. Dubois, Y. Gauthier, E.G.D. Giner-Demange, T. Hamelin, M. Oublaid, T. Papaevangelou, G. Perreu, B. Pottin, Y. Sauce, J. Schwindling, L. Seguí, F. Senée, L. Thulliez, O. Tuske, D.U. Uriot CEA-IRFU, Gif-sur-Yvette, France B. Annighöfer, A. Menelle, F. Ott LLB, Gif-Sur-Yvette, France
	Over the past few years, CEA-Saclay has been actively engaged in R&D activities focused on high-intensity proton and deuteron beams. In particular, the high-intensity proton injector IPHI has been designed and developed with the primary objective of accelerating a continuous beam of 100 mA to 3 MeV. This machine consists of a high-intensity ECR ion source, a low-energy beam line, a 352 MHz RFQ, and a medium-energy transport line equipped with diagnostics. The commissioning of the IPHI facility started several years ago with a proton beam operating at a low duty cycle (0.1%) and a current of 65 mA. Since then, significant progress has been made, resulting in an accelerated beam power exceeding 30 kW. Following this achievement, a neutron production target with a polyethylene moderator was installed and successfully operated. In addition, extensive measurements have been conducted to thoroughly characterize the beam accelerated by IPHI and its transport through the beam lines. We have developed an end-to-end numerical model of the IPHI accelerator and validated it against experimental data. The simulation results are compared with the measured values and discussed in detail.
	Slides TUC1I2 [5.582 MB]
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUC1C1	Effect of Three-Dimensional Quadrupole Magnet Model on Beam Dynamics in the FODO Line at the Spallation Neutron Source Beam Test Facility	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	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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUC2I1	High Availability Oriented Physics design for CiADS Proton Linac
	S.H. Liu, W.L. Chen, W.P. Dou, Y. He, Y.S. Qin, Z.J. Wang IMP/CAS, Lanzhou, People’s Republic of China
	CiADS is the world’s first Accelerator Driven System with a Mega-watt beam power. The linac of CiADS consists of a 500 MeV and 5 mA with five-family superconducting resonators located directly downstream of the Radio Frequency Quadrupole (RFQ). The most significant challenge in designing the superconducting linac for CiADS is to ensure high-reliability operation with minimal beam loss control at 10^-7 level and availability maximization through specifically designed hardware and software. In this presentation, we will discuss the physical design of the superconducting linac, including the fault compensation based on beam loss control and beam loss analysis during commissioning .
	Slides TUC2I1 [8.496 MB]
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUC2I2	SNS Linac Beam Dynamics: What We Understand, and What We Don’t	91
	A.P. Shishlo ORNL, Oak Ridge, Tennessee, USA
	Funding: This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. At this moment, the Spallation Neutron Source linac accelerates H⁻ ions to 1.05 GeV before they injected into the ring. The beam power on the target is 1.7 MW. The linac includes three main parts - a front-end with ion source, RFQ, and Medium Energy Beam Transport (MEBT) section; a normal temperature linac with Drift Tube Linac (DTL) and Coupled Cavities Linac (CCL); and superconducting linac (SCL). The linac has been in operation since it was commissioned in 2005. This talk discusses the results of beam dynamics studies, existing diagnostic devices, simulation codes and models used in analysis, development and results of linac tuning procedures, and beam loss reduction efforts performed at the SNS linac for 18 years. Considerations about future beam physics experiments and simulations software improvements are presented.
	Slides TUC2I2 [1.814 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC2I2
About •	Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 25 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUC2C1	Beam Physics Simulation Studies of 70 Mev ISIS Injector Linac	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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUC2C2	Evaluating PyORBIT as Unified Simulation Tool for Beam-Dynamics Modeling of the ESS Linac	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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA3I1	Synchronous Phases and Transit Time Factor	241
	J.-M. Lagniel GANIL, Caen, France
	Synchronous phases (¿s) and transit time factors (T) are THE key parameters for linac designs and operations. While the couple (¿s, T) is still our way of thinking the longitudinal beam dynamics, it is important to have in mind that the original ¿Panofsky¿ definition of these parameters is no longer valid in the case of high accelerating gradients leading to high particle velocity changes and in the case of multi-gap cavities. In this case, a new (¿s, T) definition allowing to keep both acceleration and longitudinal focusing properties is proposed. Examples are given in the SPIRAL2 linac case.
	Slides WEA3I1 [2.369 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA3I1
About •	Received ※ 27 September 2023 — Revised ※ 12 October 2023 — Accepted ※ 13 October 2023 — Issued ※ 17 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA3I2	Particle Resonances’ Domination Over Parametric Instabilities and Their Mitigation
	D. Jeon, J.-H. Jang IBS, Daejeon, Republic of Korea Y.L. Cheon, M. Chung UNIST, Ulsan, Republic of Korea
	Studies have clarified the differences between the particle resonances and the parametric resonances (instabilities). Particle resonances dominate over parametric instabilities in resonance stopbands for non-KV beams, and higher order parametric instabilities are not manifested for Gaussian beams. Also mitigation of the 4th order particle resonance is studied using beam spinning by introducing angular momentum.
	Slides WEA3I2 [2.857 MB]
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA3C1	The Tracking Code RF-Track and Its Application	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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA3C2	Benchmarking of PATH and RF-Track in the Simulation of Linac4	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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA3C3	Differential Algebra for Accelerator Optimization with Truncated Green’s Function	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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA4I1	Development of Non-Destructive Beam Envelope Measurements Using BPMs for Low Beta Heavy Ion Beams in SRF Cavities	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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA4I2	Linac4 Source and Low Energy Experience and Challenges	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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA4C1	Beam Loss Studies in the CSNS Linac	297
	J. Peng, X.Y. Feng, Y. Han, H.C. Liu, X.B. Luo IHEP CSNS, Guangdong Province, People’s Republic of China S. Fu, M.Y. Huang, Y. Li, Z.P. Li, X. Liu, S. Wang, Y. Yuan IHEP, Beijing, People’s Republic of China S.Y. Xu DNSC, Dongguan, People’s Republic of China
	The China Spallation Neutron Source¿CSNS¿accelerator comprises an 80MeV linac and a 1.6GeV rapid cycling synchrotron. It started operation in 2018, and the beam power delivered to the target has increased from 20kW to 140kW, step by step. Various beam loss studies have been performed through the accelerator to improve the beam power and availability. For the CSNS linac, the primary source of the beam loss is the halo generated by beam mismatches. In the upgrade plan of the CSNS, the beam current will increase five times, which requires more strict beam loss control. Much work is done during the design phase to keep the loss down to 1W/m of loss limit. This paper will report results obtained from beam experiments and optimization methods applied to the CSNS linac upgrade design.
	Slides WEA4C1 [3.736 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA4C1
About •	Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 13 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA4C2	Beam Loss Simulations for the Proposed TATTOOS Beamline at HIPA	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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THA2C1	Measurement of Transverse Beam Emittance for a High-Intensity Proton Injector	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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THA2C2	Comparison of Longitudinal Emittance of Various RFQs	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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THA2C3	Periodic Solution for Transport of Intense and Coupled Coasting Beams Through Quadrupole Channels	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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THA2C4	Alternating Phase Focusing Under Influence of Space Charge Defocusing	377
	S. Lauber, W.A. Barth, R. Kalleicher, M. Miski-Oglu HIM, Mainz, Germany W.A. Barth, M. Miski-Oglu, S. Yaramyshev GSI, Darmstadt, Germany W.A. Barth KPH, Mainz, Germany
	Alternating phase focusing (APF) recently emerged as a promising beam dynamics concept for accelerating bunched proton or ion beams in drift tube linear accelerators, eliminating the need for additional transverse and longitudinal focusing lenses. The performance of APF systems, similar to radio frequency quadrupoles, heavily relies on the employed focusing lattice, including the particle synchronous phase in each gap, as well as various hyperparameters such as the number of gaps, the focusing gradient, and the required beam acceptance. However, to fully utilize the cost advantages and mechanical simplicity of APF drift tube linacs, specialized software tools are necessary to streamline the accelerator development process. After successful developement of the HELIAC-APF-IH-DTL for low current and continuous wave duty cycle, this paper presents the design concepts for APF cavities tailored for high-current applications, aiming to facilitate the design and implementation of APF-based accelerators.
	Slides THA2C4 [4.986 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THA2C4
About •	Received ※ 06 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 18 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THAFP06	Beam Dynamics Study of a 400 kW D⁺ Linear Accelerator to Generate Fusion-Like Neutrons for Breeding Blanket Tests in Korea	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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THAFP07	Preliminary Results on Transverse Phase Space Tomography at KOMAC	415
	S. Lee, J.J. Dang, D.-H. Kim, H.S. Kim, H.-J. Kwon, S.P. Yun KOMAC, KAERI, Gyeongju, Republic of Korea
	Funding: This work has been supported through KOMAC operation fund of KAERI by Ministry of Science and ICT, the Korean government (KAERI ID no. : 524320-23) Beam loss is a critical issue to be avoid in high power proton accelerators due to machine protection from radiation. Nonlinear processes add higher order moments and cause halo and tail structures to a beam, resulting in beam losses. Hence it becomes more important to characterize beams for high power accelerators. Conventional beam diagnostic methods can measure only approximate elliptical features of a beam and are not suitable for high power beams. Tomography method reconstructs a multidimensional distribution from its lower-dimensional projections. We used this method to reconstruct the 4D transverse (x, x’, y, y’) phase space distribution of the beam from the accelerator at KOMAC (Korea Multipurpose Accelerator Complex). RFQ BTS (Radio Frequency Quadrupole Beam Test System) was constructed and commissioned in 2022. In the BTS, we performed tomography experiements and obtained preliminary results on 4D transverse phase space beam distribution. We also have applied the tomography measurement techniques to the 100 MeV proton linac. In this paper, we describe the tomography measurement system and present the preliminary results obtained from the BTS and the 100 MeV proton linac.
	Slides THAFP07 [2.018 MB]
	Poster THAFP07 [1.035 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP07
About •	Received ※ 01 October 2023 — Revised ※ 05 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 13 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP06	RFQ Upgrades for IFMIF-DONES	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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP08	Simulation Studies on the Low Energy Beam Transfer (LEBT) System of the ISIS Neutron Spallation Source	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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRA2I2	Summary of the Working Group B	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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

MOA2I3

Accelerator Challenges at ESS

M.E. Eshraqi
ESS, Lund, Sweden

The European Spallation Source (ESS), undergoing concurrent installation, testing and beam commissioning in Lund, Sweden, will be the brightest source of cold neutrons once the driving proton linac reaches the intermediate energy of 800 MeV and a power of 2 MW. The final goal of ESS is to deliver a 2 GeV beam of protons with an average power of 5 MW to target. The high brightness of the neutron source is achieved by optimization of the rotating tungsten target and the innovative butterfly neutron moderator. The high beam power of the linac demands high-quality beam production, efficient acceleration, and near lossless transport of a high current beam. All of these impose strict requirements on the design and beam commissioning of this machine. The linac is being commissioned in several steps as the installation progresses. This talk presents the status of the project, challenges in the accelerator and updates on the beam commissioning.

Slides MOA2I3 [19.436 MB]

Cite •

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

TUC1I1

Multi-beam Operation of LANSCE Accelerator Facility

58

Y.K. Batygin
LANL, Los Alamos, New Mexico, USA

The unique feature of the LANSCE accelerator facility is the simultaneous delivering of beams to five experimental targets. Proton beam with energy of 100-MeV is delivered to Isotope Production Facility (IPF), while 800-MeV H⁻ beams are distributed to four experimental areas: the Lujan Neutron Scattering Center, the Weapons Neutron Research facility (WNR), the Proton Radiography facility (pRad), and the Ultra-Cold Neutron facility (UCN). Multi-beam operation of accelerator facility requires careful optimization of beam losses, which is achieved by precise tuning of the beam, imposing restriction on amplitudes and phases of RF sections, application of beam-based alignment, control of H⁻ beam stripping, optimization of ion sources performance and low-energy beam transport operation under space-charge neutralization. The near - term plans are to replace obsolete systems of the LANSCE linear accelerator with modern Front End, which is the part of Los Alamos Modernization Project (LAMP). This paper summarizes experimental results obtained during operation of LANSCE accelerator facility and considers plans to expand performance of the accelerator for near-and long-term operations.

Slides TUC1I1 [10.013 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC1I1

About •

Received ※ 30 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 31 October 2023

Cite •

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

TUC1I2

30 kW Beam Commissioning of the High-Intensity Proton Accelerator IPHI: Experiments, Simulations and Space Charge

N. Chauvin, B. Bolzon, A.C. Chauveau, D. Chirpaz, M.J. Desmons, A. Dubois, Y. Gauthier, E.G.D. Giner-Demange, T. Hamelin, M. Oublaid, T. Papaevangelou, G. Perreu, B. Pottin, Y. Sauce, J. Schwindling, L. Seguí, F. Senée, L. Thulliez, O. Tuske, D.U. Uriot
CEA-IRFU, Gif-sur-Yvette, France
B. Annighöfer, A. Menelle, F. Ott
LLB, Gif-Sur-Yvette, France

Over the past few years, CEA-Saclay has been actively engaged in R&D activities focused on high-intensity proton and deuteron beams. In particular, the high-intensity proton injector IPHI has been designed and developed with the primary objective of accelerating a continuous beam of 100 mA to 3 MeV. This machine consists of a high-intensity ECR ion source, a low-energy beam line, a 352 MHz RFQ, and a medium-energy transport line equipped with diagnostics. The commissioning of the IPHI facility started several years ago with a proton beam operating at a low duty cycle (0.1%) and a current of 65 mA. Since then, significant progress has been made, resulting in an accelerated beam power exceeding 30 kW. Following this achievement, a neutron production target with a polyethylene moderator was installed and successfully operated. In addition, extensive measurements have been conducted to thoroughly characterize the beam accelerated by IPHI and its transport through the beam lines. We have developed an end-to-end numerical model of the IPHI accelerator and validated it against experimental data. The simulation results are compared with the measured values and discussed in detail.

Slides TUC1I2 [5.582 MB]

Cite •

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

TUC1C1

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

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

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

Cite •

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

TUC2I1

High Availability Oriented Physics design for CiADS Proton Linac

S.H. Liu, W.L. Chen, W.P. Dou, Y. He, Y.S. Qin, Z.J. Wang
IMP/CAS, Lanzhou, People’s Republic of China

CiADS is the world’s first Accelerator Driven System with a Mega-watt beam power. The linac of CiADS consists of a 500 MeV and 5 mA with five-family superconducting resonators located directly downstream of the Radio Frequency Quadrupole (RFQ). The most significant challenge in designing the superconducting linac for CiADS is to ensure high-reliability operation with minimal beam loss control at 10^-7 level and availability maximization through specifically designed hardware and software. In this presentation, we will discuss the physical design of the superconducting linac, including the fault compensation based on beam loss control and beam loss analysis during commissioning .

Slides TUC2I1 [8.496 MB]

Cite •

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

TUC2I2

SNS Linac Beam Dynamics: What We Understand, and What We Don’t

91

A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA

Funding: This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.
At this moment, the Spallation Neutron Source linac accelerates H⁻ ions to 1.05 GeV before they injected into the ring. The beam power on the target is 1.7 MW. The linac includes three main parts - a front-end with ion source, RFQ, and Medium Energy Beam Transport (MEBT) section; a normal temperature linac with Drift Tube Linac (DTL) and Coupled Cavities Linac (CCL); and superconducting linac (SCL). The linac has been in operation since it was commissioned in 2005. This talk discusses the results of beam dynamics studies, existing diagnostic devices, simulation codes and models used in analysis, development and results of linac tuning procedures, and beam loss reduction efforts performed at the SNS linac for 18 years. Considerations about future beam physics experiments and simulations software improvements are presented.

Slides TUC2I2 [1.814 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC2I2

About •

Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 25 October 2023

Cite •

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

TUC2C1

Beam Physics Simulation Studies of 70 Mev ISIS Injector Linac

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

Cite •

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

TUC2C2

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

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

Cite •

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

WEA3I1

Synchronous Phases and Transit Time Factor

241

J.-M. Lagniel
GANIL, Caen, France

Synchronous phases (¿s) and transit time factors (T) are THE key parameters for linac designs and operations. While the couple (¿s, T) is still our way of thinking the longitudinal beam dynamics, it is important to have in mind that the original ¿Panofsky¿ definition of these parameters is no longer valid in the case of high accelerating gradients leading to high particle velocity changes and in the case of multi-gap cavities. In this case, a new (¿s, T) definition allowing to keep both acceleration and longitudinal focusing properties is proposed. Examples are given in the SPIRAL2 linac case.

Slides WEA3I1 [2.369 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA3I1

About •

Received ※ 27 September 2023 — Revised ※ 12 October 2023 — Accepted ※ 13 October 2023 — Issued ※ 17 October 2023

Cite •

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

WEA3I2

Particle Resonances’ Domination Over Parametric Instabilities and Their Mitigation

D. Jeon, J.-H. Jang
IBS, Daejeon, Republic of Korea
Y.L. Cheon, M. Chung
UNIST, Ulsan, Republic of Korea

Studies have clarified the differences between the particle resonances and the parametric resonances (instabilities). Particle resonances dominate over parametric instabilities in resonance stopbands for non-KV beams, and higher order parametric instabilities are not manifested for Gaussian beams. Also mitigation of the 4th order particle resonance is studied using beam spinning by introducing angular momentum.

Slides WEA3I2 [2.857 MB]

Cite •

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

WEA3C1

The Tracking Code RF-Track and Its Application

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

Cite •

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

WEA3C2

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

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

Cite •

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

WEA3C3

Differential Algebra for Accelerator Optimization with Truncated Green’s Function

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

Cite •

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

WEA4I1

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

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

Cite •

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

WEA4I2

Linac4 Source and Low Energy Experience and Challenges

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

Cite •

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

WEA4C1

Beam Loss Studies in the CSNS Linac

297

J. Peng, X.Y. Feng, Y. Han, H.C. Liu, X.B. Luo
IHEP CSNS, Guangdong Province, People’s Republic of China
S. Fu, M.Y. Huang, Y. Li, Z.P. Li, X. Liu, S. Wang, Y. Yuan
IHEP, Beijing, People’s Republic of China
S.Y. Xu
DNSC, Dongguan, People’s Republic of China

The China Spallation Neutron Source¿CSNS¿accelerator comprises an 80MeV linac and a 1.6GeV rapid cycling synchrotron. It started operation in 2018, and the beam power delivered to the target has increased from 20kW to 140kW, step by step. Various beam loss studies have been performed through the accelerator to improve the beam power and availability. For the CSNS linac, the primary source of the beam loss is the halo generated by beam mismatches. In the upgrade plan of the CSNS, the beam current will increase five times, which requires more strict beam loss control. Much work is done during the design phase to keep the loss down to 1W/m of loss limit. This paper will report results obtained from beam experiments and optimization methods applied to the CSNS linac upgrade design.

Slides WEA4C1 [3.736 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA4C1

About •

Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 13 October 2023

Cite •

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

WEA4C2

Beam Loss Simulations for the Proposed TATTOOS Beamline at HIPA

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

Cite •

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

THA2C1

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

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

Cite •

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

THA2C2

Comparison of Longitudinal Emittance of Various RFQs

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

Cite •

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

THA2C3

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

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

Cite •

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

THA2C4

Alternating Phase Focusing Under Influence of Space Charge Defocusing

377

S. Lauber, W.A. Barth, R. Kalleicher, M. Miski-Oglu
HIM, Mainz, Germany
W.A. Barth, M. Miski-Oglu, S. Yaramyshev
GSI, Darmstadt, Germany
W.A. Barth
KPH, Mainz, Germany

Alternating phase focusing (APF) recently emerged as a promising beam dynamics concept for accelerating bunched proton or ion beams in drift tube linear accelerators, eliminating the need for additional transverse and longitudinal focusing lenses. The performance of APF systems, similar to radio frequency quadrupoles, heavily relies on the employed focusing lattice, including the particle synchronous phase in each gap, as well as various hyperparameters such as the number of gaps, the focusing gradient, and the required beam acceptance. However, to fully utilize the cost advantages and mechanical simplicity of APF drift tube linacs, specialized software tools are necessary to streamline the accelerator development process. After successful developement of the HELIAC-APF-IH-DTL for low current and continuous wave duty cycle, this paper presents the design concepts for APF cavities tailored for high-current applications, aiming to facilitate the design and implementation of APF-based accelerators.

Slides THA2C4 [4.986 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THA2C4

About •

Received ※ 06 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 18 October 2023

Cite •

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

THAFP06

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

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

Cite •

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

THAFP07

Preliminary Results on Transverse Phase Space Tomography at KOMAC

415

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

Funding: This work has been supported through KOMAC operation fund of KAERI by Ministry of Science and ICT, the Korean government (KAERI ID no. : 524320-23)
Beam loss is a critical issue to be avoid in high power proton accelerators due to machine protection from radiation. Nonlinear processes add higher order moments and cause halo and tail structures to a beam, resulting in beam losses. Hence it becomes more important to characterize beams for high power accelerators. Conventional beam diagnostic methods can measure only approximate elliptical features of a beam and are not suitable for high power beams. Tomography method reconstructs a multidimensional distribution from its lower-dimensional projections. We used this method to reconstruct the 4D transverse (x, x’, y, y’) phase space distribution of the beam from the accelerator at KOMAC (Korea Multipurpose Accelerator Complex). RFQ BTS (Radio Frequency Quadrupole Beam Test System) was constructed and commissioned in 2022. In the BTS, we performed tomography experiements and obtained preliminary results on 4D transverse phase space beam distribution. We also have applied the tomography measurement techniques to the 100 MeV proton linac. In this paper, we describe the tomography measurement system and present the preliminary results obtained from the BTS and the 100 MeV proton linac.

Slides THAFP07 [2.018 MB]

Poster THAFP07 [1.035 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP07

About •

Received ※ 01 October 2023 — Revised ※ 05 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 13 October 2023

Cite •

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

THBP06

RFQ Upgrades for IFMIF-DONES

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

Cite •

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

THBP08

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

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

Cite •

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

FRA2I2

Summary of the Working Group B

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

Cite •

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