IPAC2021 - Classification: MC4: Hadron Accelerators / T12 Beam Injection/Extraction and Transport

Paper	Title	Page
MOPAB180	AGS Dynamic Aperture at Injection of Polarized Protons and Helions	610
	K. Hock, H. Huang, F. Méot, N. Tsoupas BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. Polarized helions are part of the physics program for the future EIC. An AC dipole has been installed in the AGS Booster to preserve polarization as helions are accelerated to \|Ggamma\|=10.5. Extraction from the AGS Booster at \|Ggamma\|=7.5 is possible but: would involve crossing an intrinsic resonance in the AGS, and would be the lowest rigidity beam injected into the AGS, and therefore experiences strong distortions of the optical functions because of the AGS two partial snakes. This lower rigidity would exacerbate the optical distortions from the snake, reducing the dynamic aperture. A comparison of the dynamic aperture of protons at Ggamma=4.5 to that of helions at \|Ggamma\|=7.5 and \|Ggamma\|=10.5 show that extraction at \|Ggamma\|=10.5 provides a larger dynamic aperture. This larger aperture would allow helions to be placed inside the spin tune gap generated by the two partial helices in AGS earlier in the cycle.
	Poster MOPAB180 [0.453 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB180
About •	paper received ※ 17 May 2021 paper accepted ※ 31 May 2021 issue date ※ 20 August 2021
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WEXB07	Transverse Beam Profile Measurements from Extraction Losses in the PS	2548
	J.R. Hunt, F. Cerutti, L.S. Esposito, M. Giovannozzi, A. Huschauer, G. Russo CERN, Geneva, Switzerland G. Russo Goethe Universität Frankfurt, Frankfurt am Main, Germany
	During Multi-Turn Extraction (MTE) of continuous beams in the Proton Synchrotron (PS) at CERN, losses are generated on the blade of both the active and non-active septum during the rise time of the extraction kickers. Utilising pCVD Diamond detectors, secondary signal generated from these losses is measured. The high time resolution of these devices allows for insight into the detail of the horizontal beam distribution during extraction, and hence useful information such as the horizontal beam emittance may be computed. In this contribution, FLUKA simulations to relate the detector response to the beam impact conditions on the blades of the two septa are presented. The dependence on the beam angle, magnetic fringe field, and positioning of the detector is explored. Finally, realistic beam distributions are used to determine expected signal profiles at each septum.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXB07
About •	paper received ※ 18 May 2021 paper accepted ※ 20 July 2021 issue date ※ 27 August 2021
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WEPAB192	Simulation Study on Double Diffuser for Loss Reduction in Slow Extraction at J-PARC Main Ring	3069
	R. Muto, Y. Arakaki, T. Kimura, S. Murasugi, K. Okamura, Y. Shirakabe, M. Tomizawa, E. Yanaoka KEK, Tokai, Ibaraki, Japan A. Matsumura Nihon Advanced Technology Co., Ltd, Ibaraki, Nakagun, Tokaimura, Japan
	J-PARC (Japan Proton Accelerator Research Complex) Main Ring delivers slow-extracted 30~GeV proton beam to various nuclear and particle physics experiments. In the slow extraction the beam loss at the electrostatic septum (ESS) is inevitable, and the beam loss reduction is a key issue to realize the high-intensity beam delivery. We carried out simulation studies on the effectiveness of the beam diffusers at the upstream of the ESS for the beam loss reduction with various materials and dimensions of the diffusers. We found out that putting two diffusers simultaneously on the beam was effective for the beam loss reduction, and the expected beam loss was 0.35 times as high as the operation without diffusers. According to the simulation results we installed the diffusers in the J-PARC Main Ring. We performed beam test with one diffuser and beam loss reduction of 60% was observed, which was in good agreement with the simulation results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB192
About •	paper received ※ 19 May 2021 paper accepted ※ 28 June 2021 issue date ※ 21 August 2021
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WEPAB193	Optimization of the Hadron Ring Stripline Injection Kicker for the EIC	3073
	M.P. Sangroula, C.J. Liaw, C. Liu, N. Tsoupas, B.P. Xiao, W. Zhang BNL, Upton, New York, USA X. Sun ANL, Lemont, Illinois, USA S. Verdú-Andrés Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy The Electron-Ion Collider (EIC) at Brookhaven National Laboratory is a high luminosity, ( ∼ 10³⁴ \textrm{cm}^-2 \textrm{s}^-1 ) accelerator facility colliding polarized electron beam with different ion species ranging from lighter nuclei (proton, deuterium) to heavier nuclei (gold, uranium). Design of a stripline injection kicker for the Hadron Storage Ring (HSR) of EIC for beams with the rigidity of ∼ 81 T-m poses some technical challenges due to expected shorter bunch spacing and higher peak current of EIC. This paper focuses on the optimization of the EIC hadron ring injection kicker. Starting from the 2D cross-section design which includes the selection of electrodes shape, we describe the optimization of the kicker’s cross-section. Then we discuss converting this 2D geometry to 3D by adding essential components for the stripline kicker and the 3D optimization techniques that we employed. Finally, we show simulation results for the optimized geometry including wakefields and Time Domain Reflection (TDR) from one feedthrough to another.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB193
About •	paper received ※ 21 May 2021 paper accepted ※ 28 June 2021 issue date ※ 14 August 2021
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WEPAB198	Beam Dynamics Design of a Synchrotron Injector with Laser-Accelerated Ions	3085
	M.Z. Tuo, X. Guan, W. Lu, P.F. Ma, Y. Wan, X.W. Wang, Q.Z. Xing, H.J. Yao, S.X. Zheng TUB, Beijing, People’s Republic of China
	We present, in this paper, the beam dynamics design of a linac injector with laser-accelerated carbon-ions for a medical synchrotron. In the design, the initial transverse divergence is reduced by two apertures. The beam is focused transversely through a quadrupole triplet lens downstream the apertures. The output energy spread of the extracted beam at the exit of the injector is compressed from ±6% to ±0.6% by a debuncher and a bend magnet system to meet the injection requirement for the synchrotron. By changing the width of imaging slit of the bend magnet system, the beam with energy of 4±0.024 MeV/u is extracted, and the particle number per shot and transverse emittances of the beam at the exit of the injector can be regulated through adjusting the slit height. The dynamics design can pave the way for the future concept research of the synchrotron injector.
	Poster WEPAB198 [1.034 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB198
About •	paper received ※ 16 May 2021 paper accepted ※ 16 June 2021 issue date ※ 18 August 2021
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WEPAB199	Study on the Important Technologies of 300MeV Upgrade for the CSNS Injection System	3089
	M.Y. Huang, C.D. Deng, L. Kang, L. Liu, Y. Liu, X. Qi, S. Wang, Q.B. Wu, Y.W. Wu, S.Y. Xu, W.Q. Zhang, Y.L. Zhang IHEP, Beijing, People’s Republic of China J.X. Chen, T. Huang, H.C. Liu IHEP CSNS, Guangdong Province, People’s Republic of China
	Funding: This work was supported by National Natural Science Foundation of China (Project Nos. U1832210 and 12075134). The China Spallation Neutron Source (CSNS-I) have achieved the design goal of 100kW beam power on the target in Feb., 2020. As the second phase of the CSNS, CSNS-II will achieve a beam power on the target of 500 kW. The injection energy of CSNS-II will be increased from 80 MeV to 300 MeV and the average beam current of the Linac will increase 5 times. Therefore, the injection system will require a complete upgrade. In this paper, the design scheme of the injection system for CSNS-II will be introduced. The key technologies of the upgrade injection system will be carefully analyzed and pre-developed, such as the pulse power supplies and their magnets, the special-shaped ceramic vacuum chambers, the main stripping foil, the stripped electron collection, and so on.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB199
About •	paper received ※ 17 May 2021 paper accepted ※ 09 June 2021 issue date ※ 21 August 2021
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WEPAB202	Thermal Analysis of a Compact Split-Coaxial CW RFQ for the IsoDAR RFQ-DIP	3097
	D. Koser, J.M. Conrad, D. Winklehner MIT, Cambridge, Massachusetts, USA H. Podlech, U. Ratzinger, M. Schuett BEVATECH, Frankfurt, Germany
	The RFQ direct injection project (RFQ-DIP) for the neutrino physics experiment IsoDAR aims at an efficient injection of a high-current H²⁺ beam into the dedicated 60 MeV driver cyclotron. Therefore, it is intended to use a compact 32.8 MHz RFQ structure of the split-coaxial type as a pre-buncher. To determine the thermal elongation of the 1.4 m long electrode rods as well as the thermal frequency detuning of the RF structure at a maximum nominal power load of 3.6 kW, an extensive thermal and structural mechanical analysis using COMSOL Multiphysics was conducted. The water heating along the cooling channels as well as the properties of heat transfer from the copper structure to the cooling water were taken into account, which required CFD simulations of the cooling water flow in the turbulent regime. Here we present the methods and results of the sophisticated thermal and structural mechanical simulations using COMSOL and provide a comparison to more simplistic simulations conducted with CST Studio Suite.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB202
About •	paper received ※ 20 May 2021 paper accepted ※ 01 July 2021 issue date ※ 14 August 2021
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WEPAB204	Layout of the New Septum Magnets for Fast Extraction in J-PARC Main Ring	3103
	S. Iwata, K. Ishii, H. Matsumoto, N. Matsumoto, Y. Sato, T. Shibata, T. Sugimoto KEK, Ibaraki, Japan
	At J-PARC Main Ring (MR), we are pursuing to improve the beam power from 500 kW to 1.3 MW by reducing the repetition cycle from 2.48 to 1.16 seconds (1 Hz operation). Additionally, we are considering the beam particles increasing by selecting a more optimal tune. The fast extraction (FX) equipment to the neutrino facility (NU) is needed to upgrade for the 1 Hz operation. We plan to replace most FX septum magnets with new ones in 2021. We report a layout of the FX line in confirmation of new beam optics and mention the beam loss during the fast extraction.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB204
About •	paper received ※ 20 May 2021 paper accepted ※ 09 June 2021 issue date ※ 27 August 2021
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WEPAB205	XiPAF Synchrotron Slow Extraction Commissioning	3106
	W.B. Ye, X. Guan, Y. Li, X.Y. Liu, M.W. Wang, X.W. Wang, Y. Yang, H.J. Yao, H.J. Zeng, S.X. Zheng TUB, Beijing, People’s Republic of China W.L. Liu, D. Wang, M.C. Wang, Z.M. Wang, Y. Yang, M.T. Zhao NINT, Shannxi, People’s Republic of China
	Xi’an 200 MeV Proton Application Facility (XiPAF) is a project to fulfill the need for the experimental simulation of the space radiation environment. It comprises a 7 MeV H⁻ linac, a 60~230 MeV proton synchrotron, and experimental stations. Slow extraction commissioning for 60 MeV proton beam in XiPAF synchrotron has been finished. After commissioning, the maximal experiment extraction efficiency with the RF-knockout (RF-KO) method can up to 85%. The reason for beam loss has been analyzed and presented in this paper. Besides, an experiment of multiple energy extraction has been conducted in XiPAF synchrotron. The proton beams of 3 different energies were successfully extracted in 1.54 s.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB205
About •	paper received ※ 18 May 2021 paper accepted ※ 07 July 2021 issue date ※ 31 August 2021
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WEPAB208	Energy Sweeping Beam Extraction by the Septum Magnet Assisted with Charge Exchange for a Hadron Therapy	3109
	T.S. Dixit, A. Shaikh SAMEER, Mumbai, India T. Adachi, T. Kawakubo, K. Takayama KEK, Ibaraki, Japan
	An energy sweeping compact rapid cycling hadron therapy based on a fast cycling induction synchrotron has been proposed by KEK and SAMEER as the next generation of hadron therapy machine . For energy sweep extraction, a C+5 beam is injected, captured and trapped in the barrier bucket. A fraction of the beam is continuously released from the barrier bucket by controlling the timing of barrier pulse generation. Released C+5 ions merge into the coasting beam and moves inwards with ramping of the guiding main magnets. Ions in the coasting beam eventually hit the carbon foil placed inside the beam chamber wall. As a result, C+5 is converted to C+6 and beam orbit is largely changed as it traverses through the downstream bending magnet. This notably facilitates C+6 beam extraction, resulting in a relatively small kick angle of the septum magnet. When the septum is excited in the same way as that of the main magnets, the extracted C+6 beam always places on the center of the irradiation beam line. LISE++ simulations demonstrated the charge exchange efficiency of almost 100 % for expected beam energy. The feasibility of the switching power supply for the septum magnet has been studied. PRAB 24, 011601 (2021)
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB208
About •	paper received ※ 14 May 2021 paper accepted ※ 22 June 2021 issue date ※ 16 August 2021
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WEPAB210	Beam Commissioning of the New 160 MeV H⁻ Injection System of the CERN PS Booster	3116
	E. Renner, S.C.P. Albright, F. Antoniou, F. Asvesta, H. Bartosik, C. Bracco, G.P. Di Giovanni, L.O. Jorat, E.H. Maclean, M. Meddahi, B. Mikulec, T. Prebibaj, G. Rumolo, P.K. Skowroński, W.J.M. Weterings CERN, Meyrin, Switzerland
	A key component to meeting the brightness targets of the LHC Injectors Upgrade (LIU) project at CERN is the new 160 MeV H⁻ charge exchange injection system into the Proton Synchrotron Booster. This system has been in beam commissioning since December 2020, optimizing the beam production schemes for tailoring different beams to the respective user-defined brightness targets. In this paper, selected measurements from the beam commissioning period are presented, characterizing the system’s flexibility to produce the required wide range of transverse emittances. The discussion focuses on the essential optimization of the injection set-up to minimize space charge driven emittance blow-up and injection errors. The results are completed by selected comparisons with multi-particle simulation models of the injection process.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB210
About •	paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 29 August 2021
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WEPAB211	Lattice Design of the Beam Transfer Line (BTL) from PIP-II LINAC to the Booster at Fermilab	3120
	M. Xiao Fermilab, Batavia, Illinois, USA
	PIP-II beam transfer line (BTL) to transport the beam from PIP-II Linac to the Booster ring at Fermilab. The latest design eliminates rolling the dipoles in the beam line to cross over the Tevatron tunnel. Also re-designed is the lattice in the region of the Booster Injection to meet the request of the civil construction needs and accommodate the constrains of the Booster injection request. A beam line to the beam absorber (BAL) is designed based on the request from the results of Mars simulations and ANASYS calculation of the absorber. Simulations with dipole and quadrupole field errors for the Beam Transport Line (BTL) to the Booster, which provides the specifications for all the magnets and Power supplies, will be presented too.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB211
About •	paper received ※ 20 May 2021 paper accepted ※ 08 July 2021 issue date ※ 31 August 2021
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WEPAB221	H⁰ Stark Stripping and Component Irradiation in Fermilab Booster	3142
	J.A. Johnstone, D.E. Johnson Fermilab, Batavia, Illinois, USA
	Funding: Work supported by Fermi Research Alliance, LLC under contract no. DE-AC02-07CH11359 In foil stripping of H⁻ some fraction of the emerging neutral H⁰ will be in excited states, which can then strip through the Stark effect in the magnetic field of the downstream orbit bump magnet. The resultant H⁺ will experience a depleted net kick compared to protons emerging from the foil and will track on trajectories different from the nominal circulating beam. This will lead to irradiation of downstream machine components. An analysis of these processes is of particular importance looking forward to the much higher beam power of the Fermilab PIP-II era. This study investigates where these errant protons will be lost, how much power is deposited, and whether this will be a shielding concern.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB221
About •	paper received ※ 11 May 2021 paper accepted ※ 09 June 2021 issue date ※ 20 August 2021
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THPAB165	5 MW Beam Power in the ESSnuSB Accumulator: A Way to Manage Foil Stripping Injection at 14 Hz Linac Pulse Rate	4072
	H. Schönauer CERN, Geneva, Switzerland Y. Zou Uppsala University, Uppsala, Sweden
	Funding: This work is supported by the European Union’s Horizon 2020 research and innovation program under grant agreement No 777419. In the past, the scenario for foil stripping consisted of splitting a linac pulse into 4 rings, or 3 or 4 intermediate pulses, and one ring. At present, the scenario, in view of laser stripping, consists of one ring, one pulse, split into four batches. Conventional stripping geometry would lead to foil evaporation under this beam load. One way out appears to be replacing the standard corner foil by a single-edge foil rotated to about 45deg. The tilted foil allows moving the injection point together with the painting bumps along the foil edge, distributing the deposited beam power over a larger foil area. Simulation results obtained with the same tools as in the past scenarios are presented. They show peak foil temperatures, which compare with the best results obtained from the past scenarios.
	Poster THPAB165 [2.205 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB165
About •	paper received ※ 11 May 2021 paper accepted ※ 21 June 2021 issue date ※ 18 August 2021
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Paper

Title

Page

AGS Dynamic Aperture at Injection of Polarized Protons and Helions

610

K. Hock, H. Huang, F. Méot, N. Tsoupas
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Polarized helions are part of the physics program for the future EIC. An AC dipole has been installed in the AGS Booster to preserve polarization as helions are accelerated to |Ggamma|=10.5. Extraction from the AGS Booster at |Ggamma|=7.5 is possible but: would involve crossing an intrinsic resonance in the AGS, and would be the lowest rigidity beam injected into the AGS, and therefore experiences strong distortions of the optical functions because of the AGS two partial snakes. This lower rigidity would exacerbate the optical distortions from the snake, reducing the dynamic aperture. A comparison of the dynamic aperture of protons at Ggamma=4.5 to that of helions at |Ggamma|=7.5 and |Ggamma|=10.5 show that extraction at |Ggamma|=10.5 provides a larger dynamic aperture. This larger aperture would allow helions to be placed inside the spin tune gap generated by the two partial helices in AGS earlier in the cycle.

Poster MOPAB180 [0.453 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB180

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paper received ※ 17 May 2021 paper accepted ※ 31 May 2021 issue date ※ 20 August 2021

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WEXB07

Transverse Beam Profile Measurements from Extraction Losses in the PS

2548

J.R. Hunt, F. Cerutti, L.S. Esposito, M. Giovannozzi, A. Huschauer, G. Russo
CERN, Geneva, Switzerland
G. Russo
Goethe Universität Frankfurt, Frankfurt am Main, Germany

During Multi-Turn Extraction (MTE) of continuous beams in the Proton Synchrotron (PS) at CERN, losses are generated on the blade of both the active and non-active septum during the rise time of the extraction kickers. Utilising pCVD Diamond detectors, secondary signal generated from these losses is measured. The high time resolution of these devices allows for insight into the detail of the horizontal beam distribution during extraction, and hence useful information such as the horizontal beam emittance may be computed. In this contribution, FLUKA simulations to relate the detector response to the beam impact conditions on the blades of the two septa are presented. The dependence on the beam angle, magnetic fringe field, and positioning of the detector is explored. Finally, realistic beam distributions are used to determine expected signal profiles at each septum.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXB07

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paper received ※ 18 May 2021 paper accepted ※ 20 July 2021 issue date ※ 27 August 2021

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WEPAB192

Simulation Study on Double Diffuser for Loss Reduction in Slow Extraction at J-PARC Main Ring

3069

R. Muto, Y. Arakaki, T. Kimura, S. Murasugi, K. Okamura, Y. Shirakabe, M. Tomizawa, E. Yanaoka
KEK, Tokai, Ibaraki, Japan
A. Matsumura
Nihon Advanced Technology Co., Ltd, Ibaraki, Nakagun, Tokaimura, Japan

J-PARC (Japan Proton Accelerator Research Complex) Main Ring delivers slow-extracted 30~GeV proton beam to various nuclear and particle physics experiments. In the slow extraction the beam loss at the electrostatic septum (ESS) is inevitable, and the beam loss reduction is a key issue to realize the high-intensity beam delivery. We carried out simulation studies on the effectiveness of the beam diffusers at the upstream of the ESS for the beam loss reduction with various materials and dimensions of the diffusers. We found out that putting two diffusers simultaneously on the beam was effective for the beam loss reduction, and the expected beam loss was 0.35 times as high as the operation without diffusers. According to the simulation results we installed the diffusers in the J-PARC Main Ring. We performed beam test with one diffuser and beam loss reduction of 60% was observed, which was in good agreement with the simulation results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB192

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paper received ※ 19 May 2021 paper accepted ※ 28 June 2021 issue date ※ 21 August 2021

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WEPAB193

Optimization of the Hadron Ring Stripline Injection Kicker for the EIC

3073

M.P. Sangroula, C.J. Liaw, C. Liu, N. Tsoupas, B.P. Xiao, W. Zhang
BNL, Upton, New York, USA
X. Sun
ANL, Lemont, Illinois, USA
S. Verdú-Andrés
Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy
The Electron-Ion Collider (EIC) at Brookhaven National Laboratory is a high luminosity, ( ∼ 10³⁴ \textrm{cm}^-2 \textrm{s}^-1 ) accelerator facility colliding polarized electron beam with different ion species ranging from lighter nuclei (proton, deuterium) to heavier nuclei (gold, uranium). Design of a stripline injection kicker for the Hadron Storage Ring (HSR) of EIC for beams with the rigidity of ∼ 81 T-m poses some technical challenges due to expected shorter bunch spacing and higher peak current of EIC. This paper focuses on the optimization of the EIC hadron ring injection kicker. Starting from the 2D cross-section design which includes the selection of electrodes shape, we describe the optimization of the kicker’s cross-section. Then we discuss converting this 2D geometry to 3D by adding essential components for the stripline kicker and the 3D optimization techniques that we employed. Finally, we show simulation results for the optimized geometry including wakefields and Time Domain Reflection (TDR) from one feedthrough to another.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB193

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paper received ※ 21 May 2021 paper accepted ※ 28 June 2021 issue date ※ 14 August 2021

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WEPAB198

Beam Dynamics Design of a Synchrotron Injector with Laser-Accelerated Ions

3085

M.Z. Tuo, X. Guan, W. Lu, P.F. Ma, Y. Wan, X.W. Wang, Q.Z. Xing, H.J. Yao, S.X. Zheng
TUB, Beijing, People’s Republic of China

We present, in this paper, the beam dynamics design of a linac injector with laser-accelerated carbon-ions for a medical synchrotron. In the design, the initial transverse divergence is reduced by two apertures. The beam is focused transversely through a quadrupole triplet lens downstream the apertures. The output energy spread of the extracted beam at the exit of the injector is compressed from ±6% to ±0.6% by a debuncher and a bend magnet system to meet the injection requirement for the synchrotron. By changing the width of imaging slit of the bend magnet system, the beam with energy of 4±0.024 MeV/u is extracted, and the particle number per shot and transverse emittances of the beam at the exit of the injector can be regulated through adjusting the slit height. The dynamics design can pave the way for the future concept research of the synchrotron injector.

Poster WEPAB198 [1.034 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB198

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paper received ※ 16 May 2021 paper accepted ※ 16 June 2021 issue date ※ 18 August 2021

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WEPAB199

Study on the Important Technologies of 300MeV Upgrade for the CSNS Injection System

3089

M.Y. Huang, C.D. Deng, L. Kang, L. Liu, Y. Liu, X. Qi, S. Wang, Q.B. Wu, Y.W. Wu, S.Y. Xu, W.Q. Zhang, Y.L. Zhang
IHEP, Beijing, People’s Republic of China
J.X. Chen, T. Huang, H.C. Liu
IHEP CSNS, Guangdong Province, People’s Republic of China

Funding: This work was supported by National Natural Science Foundation of China (Project Nos. U1832210 and 12075134).
The China Spallation Neutron Source (CSNS-I) have achieved the design goal of 100kW beam power on the target in Feb., 2020. As the second phase of the CSNS, CSNS-II will achieve a beam power on the target of 500 kW. The injection energy of CSNS-II will be increased from 80 MeV to 300 MeV and the average beam current of the Linac will increase 5 times. Therefore, the injection system will require a complete upgrade. In this paper, the design scheme of the injection system for CSNS-II will be introduced. The key technologies of the upgrade injection system will be carefully analyzed and pre-developed, such as the pulse power supplies and their magnets, the special-shaped ceramic vacuum chambers, the main stripping foil, the stripped electron collection, and so on.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB199

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paper received ※ 17 May 2021 paper accepted ※ 09 June 2021 issue date ※ 21 August 2021

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WEPAB202

Thermal Analysis of a Compact Split-Coaxial CW RFQ for the IsoDAR RFQ-DIP

3097

D. Koser, J.M. Conrad, D. Winklehner
MIT, Cambridge, Massachusetts, USA
H. Podlech, U. Ratzinger, M. Schuett
BEVATECH, Frankfurt, Germany

The RFQ direct injection project (RFQ-DIP) for the neutrino physics experiment IsoDAR aims at an efficient injection of a high-current H²⁺ beam into the dedicated 60 MeV driver cyclotron. Therefore, it is intended to use a compact 32.8 MHz RFQ structure of the split-coaxial type as a pre-buncher. To determine the thermal elongation of the 1.4 m long electrode rods as well as the thermal frequency detuning of the RF structure at a maximum nominal power load of 3.6 kW, an extensive thermal and structural mechanical analysis using COMSOL Multiphysics was conducted. The water heating along the cooling channels as well as the properties of heat transfer from the copper structure to the cooling water were taken into account, which required CFD simulations of the cooling water flow in the turbulent regime. Here we present the methods and results of the sophisticated thermal and structural mechanical simulations using COMSOL and provide a comparison to more simplistic simulations conducted with CST Studio Suite.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB202

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paper received ※ 20 May 2021 paper accepted ※ 01 July 2021 issue date ※ 14 August 2021

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WEPAB204

Layout of the New Septum Magnets for Fast Extraction in J-PARC Main Ring

3103

S. Iwata, K. Ishii, H. Matsumoto, N. Matsumoto, Y. Sato, T. Shibata, T. Sugimoto
KEK, Ibaraki, Japan

At J-PARC Main Ring (MR), we are pursuing to improve the beam power from 500 kW to 1.3 MW by reducing the repetition cycle from 2.48 to 1.16 seconds (1 Hz operation). Additionally, we are considering the beam particles increasing by selecting a more optimal tune. The fast extraction (FX) equipment to the neutrino facility (NU) is needed to upgrade for the 1 Hz operation. We plan to replace most FX septum magnets with new ones in 2021. We report a layout of the FX line in confirmation of new beam optics and mention the beam loss during the fast extraction.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB204

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paper received ※ 20 May 2021 paper accepted ※ 09 June 2021 issue date ※ 27 August 2021

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WEPAB205

XiPAF Synchrotron Slow Extraction Commissioning

3106

W.B. Ye, X. Guan, Y. Li, X.Y. Liu, M.W. Wang, X.W. Wang, Y. Yang, H.J. Yao, H.J. Zeng, S.X. Zheng
TUB, Beijing, People’s Republic of China
W.L. Liu, D. Wang, M.C. Wang, Z.M. Wang, Y. Yang, M.T. Zhao
NINT, Shannxi, People’s Republic of China

Xi’an 200 MeV Proton Application Facility (XiPAF) is a project to fulfill the need for the experimental simulation of the space radiation environment. It comprises a 7 MeV H⁻ linac, a 60~230 MeV proton synchrotron, and experimental stations. Slow extraction commissioning for 60 MeV proton beam in XiPAF synchrotron has been finished. After commissioning, the maximal experiment extraction efficiency with the RF-knockout (RF-KO) method can up to 85%. The reason for beam loss has been analyzed and presented in this paper. Besides, an experiment of multiple energy extraction has been conducted in XiPAF synchrotron. The proton beams of 3 different energies were successfully extracted in 1.54 s.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB205

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paper received ※ 18 May 2021 paper accepted ※ 07 July 2021 issue date ※ 31 August 2021

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WEPAB208

Energy Sweeping Beam Extraction by the Septum Magnet Assisted with Charge Exchange for a Hadron Therapy

3109

T.S. Dixit, A. Shaikh
SAMEER, Mumbai, India
T. Adachi, T. Kawakubo, K. Takayama
KEK, Ibaraki, Japan

An energy sweeping compact rapid cycling hadron therapy based on a fast cycling induction synchrotron has been proposed by KEK and SAMEER as the next generation of hadron therapy machine *. For energy sweep extraction, a C+5 beam is injected, captured and trapped in the barrier bucket. A fraction of the beam is continuously released from the barrier bucket by controlling the timing of barrier pulse generation. Released C+5 ions merge into the coasting beam and moves inwards with ramping of the guiding main magnets. Ions in the coasting beam eventually hit the carbon foil placed inside the beam chamber wall. As a result, C+5 is converted to C+6 and beam orbit is largely changed as it traverses through the downstream bending magnet. This notably facilitates C+6 beam extraction, resulting in a relatively small kick angle of the septum magnet. When the septum is excited in the same way as that of the main magnets, the extracted C+6 beam always places on the center of the irradiation beam line. LISE++ simulations demonstrated the charge exchange efficiency of almost 100 % for expected beam energy. The feasibility of the switching power supply for the septum magnet has been studied.
* PRAB 24, 011601 (2021)

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB208

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paper received ※ 14 May 2021 paper accepted ※ 22 June 2021 issue date ※ 16 August 2021

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WEPAB210

Beam Commissioning of the New 160 MeV H⁻ Injection System of the CERN PS Booster

3116

E. Renner, S.C.P. Albright, F. Antoniou, F. Asvesta, H. Bartosik, C. Bracco, G.P. Di Giovanni, L.O. Jorat, E.H. Maclean, M. Meddahi, B. Mikulec, T. Prebibaj, G. Rumolo, P.K. Skowroński, W.J.M. Weterings
CERN, Meyrin, Switzerland

A key component to meeting the brightness targets of the LHC Injectors Upgrade (LIU) project at CERN is the new 160 MeV H⁻ charge exchange injection system into the Proton Synchrotron Booster. This system has been in beam commissioning since December 2020, optimizing the beam production schemes for tailoring different beams to the respective user-defined brightness targets. In this paper, selected measurements from the beam commissioning period are presented, characterizing the system’s flexibility to produce the required wide range of transverse emittances. The discussion focuses on the essential optimization of the injection set-up to minimize space charge driven emittance blow-up and injection errors. The results are completed by selected comparisons with multi-particle simulation models of the injection process.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB210

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paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 29 August 2021

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WEPAB211

Lattice Design of the Beam Transfer Line (BTL) from PIP-II LINAC to the Booster at Fermilab

3120

M. Xiao
Fermilab, Batavia, Illinois, USA

PIP-II beam transfer line (BTL) to transport the beam from PIP-II Linac to the Booster ring at Fermilab. The latest design eliminates rolling the dipoles in the beam line to cross over the Tevatron tunnel. Also re-designed is the lattice in the region of the Booster Injection to meet the request of the civil construction needs and accommodate the constrains of the Booster injection request. A beam line to the beam absorber (BAL) is designed based on the request from the results of Mars simulations and ANASYS calculation of the absorber. Simulations with dipole and quadrupole field errors for the Beam Transport Line (BTL) to the Booster, which provides the specifications for all the magnets and Power supplies, will be presented too.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB211

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paper received ※ 20 May 2021 paper accepted ※ 08 July 2021 issue date ※ 31 August 2021

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WEPAB221

H⁰ Stark Stripping and Component Irradiation in Fermilab Booster

3142

J.A. Johnstone, D.E. Johnson
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Fermi Research Alliance, LLC under contract no. DE-AC02-07CH11359
In foil stripping of H⁻ some fraction of the emerging neutral H⁰ will be in excited states, which can then strip through the Stark effect in the magnetic field of the downstream orbit bump magnet. The resultant H⁺ will experience a depleted net kick compared to protons emerging from the foil and will track on trajectories different from the nominal circulating beam. This will lead to irradiation of downstream machine components. An analysis of these processes is of particular importance looking forward to the much higher beam power of the Fermilab PIP-II era. This study investigates where these errant protons will be lost, how much power is deposited, and whether this will be a shielding concern.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB221

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paper received ※ 11 May 2021 paper accepted ※ 09 June 2021 issue date ※ 20 August 2021

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THPAB165

5 MW Beam Power in the ESSnuSB Accumulator: A Way to Manage Foil Stripping Injection at 14 Hz Linac Pulse Rate

4072

H. Schönauer
CERN, Geneva, Switzerland
Y. Zou
Uppsala University, Uppsala, Sweden

Funding: This work is supported by the European Union’s Horizon 2020 research and innovation program under grant agreement No 777419.
In the past, the scenario for foil stripping consisted of splitting a linac pulse into 4 rings, or 3 or 4 intermediate pulses, and one ring. At present, the scenario, in view of laser stripping, consists of one ring, one pulse, split into four batches. Conventional stripping geometry would lead to foil evaporation under this beam load. One way out appears to be replacing the standard corner foil by a single-edge foil rotated to about 45deg. The tilted foil allows moving the injection point together with the painting bumps along the foil edge, distributing the deposited beam power over a larger foil area. Simulation results obtained with the same tools as in the past scenarios are presented. They show peak foil temperatures, which compare with the best results obtained from the past scenarios.

Poster THPAB165 [2.205 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB165

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paper received ※ 11 May 2021 paper accepted ※ 21 June 2021 issue date ※ 18 August 2021

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