Keyword: injection
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MOA1I1 Beam Performance with the LHC Injectors Upgrade brightness, operation, emittance, target 1
 
  • G. Rumolo, S.C.P. Albright, R. Alemany-Fernández, M.E. Angoletta, C. Antuono, T. Argyropoulos, F. Asvesta, M.J. Barnes, H. Bartosik, P. Baudrenghien, G. Bellodi, N. Biancacci, C. Bracco, N. Bruchon, E. Carlier, J. Coupard, H. Damerau, G.P. Di Giovanni, A. Findlay, M.A. Fraser, A. Funken, R. Garoby, S.S. Gilardoni, B. Goddard, G. Hagmann, K. Hanke, A. Huschauer, G. Iadarola, V. Kain, I. Karpov, J.-B. Lallement, A. Lasheen, T.E. Levens, K.S.B. Li, A.M. Lombardi, E.H. Maclean, D. Manglunki, I. Mases Solé, M. Meddahi, L. Mether, B. Mikulec, E. Montesinos, Y. Papaphilippou, G. Papotti, K. Paraschou, C. Pasquino, F. Pedrosa, T. Prebibaj, S. Prodon, D. Quartullo, F. Roncarolo, B. Salvant, M. Schenk, R. Scrivens, E.N. Shaposhnikova, L. Sito, P.K. Skowroński, A. Spierer, R. Steerenberg, M. Sullivan, F.M. Velotti, R. Veness, C. Vollinger, R. Wegner, C. Zannini, E. de la Fuente
    CERN, Meyrin, Switzerland
  • T. Prebibaj
    IAP, Frankfurt am Main, Germany
  
  The LHC Injectors Upgrade (LIU) project was put in place between 2010 and 2021 to increase the intensity and brightness in the LHC injectors to match the challenging requirements of the High-Luminosity LHC (HL-LHC) project, while ensuring reliable operation of the injectors complex up to the end of the HL-LHC era (ca. 2040). During the 2019-2020 CERN accelerators shutdown, extensive hardware modifications were implemented in the entire LHC proton and ion injection chains, involving the new Linac4, the Proton Synchrotron Booster (PSB), the Proton Synchrotron (PS), the Super Proton Synchrotron (SPS) and the ion PS injectors, i.e. the Linac3 and the Low Energy Ion Ring (LEIR). Since 2021, beams have been recommissioned throughout the injectors’ chain and the beam parameters are being gradually ramped up to meet the LIU specifications using new beam dynamics solutions adapted to the upgraded accelerators. This paper focuses on the proton beams and describes the current state of the art.  
slides icon Slides MOA1I1 [10.002 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-MOA1I1  
About • Received ※ 29 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 18 October 2023
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MOA1I3 Intense Beam Issues in CSNS Accelerator Beam Commissioning space-charge, MMI, sextupole, cavity 16
 
  • L. Huang, H.Y. Liu, X.H. Lu, X.B. Luo, J. Peng, L. Rao
    IHEP CSNS, Guangdong Province, People’s Republic of China
  • Y.W. An, J. Chen, M.Y. Huang, Y. Li, Z.P. Li, S. Wang
    IHEP, Beijing, People’s Republic of China
  • S.Y. Xu
    DNSC, Dongguan, People’s Republic of China
  
  The China Spallation Neutron Source (CSNS) consists of an 80 MeV H⁻ Linac, a 1.6 GeV Rapid Cycling Synchrotron (RCS), beam transport lines, a target station, and three spectrometers. The CSNS design beam power is 100 kW, with the capability to upgrade to 500 kW. In August 2018, CSNS was officially opened to domestic and international users. By February 2020, the beam power had reached 100 kW, and through improvements such as adding harmonic cavities, the beam power was increased to 140 kW. During the beam commissioning process, the beam loss caused by space charge effects was the most significant factor limiting the increase in beam power. Additionally, unexpected collective effects were observed, including coherent oscillations of the bunches, after the beam power reached 50 kW. Through a series of measures, the space charge effects and collective instabilities causing beam loss were effectively controlled. This paper mainly introduces the strong beam effects discovered during the beam commissioning at CSNS and their suppression methods. It also briefly discusses the research on beam space charge effects and collective effects in the beam dynamics design of CSNS-II project.  
slides icon Slides MOA1I3 [8.597 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-MOA1I3  
About • Received ※ 01 October 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 24 October 2023
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MOA4I1 Design of a Fixed-Field Accelerating Ring for High Power Applications extraction, synchrotron, resonance, lattice 38
 
  • S. Machida
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  
  A fixed field accelerating ring (FFA) has some advantage to achieve high beam power over conventional ring accelerators. It would be also a sustainable option as future proton drivers. We will discuss the design of an FFA taking a future upgrade plan of ISIS (ISIS-II) as an example.  
slides icon Slides MOA4I1 [14.313 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-MOA4I1  
About • Received ※ 01 October 2023 — Revised ※ 05 October 2023 — Accepted ※ 15 October 2023 — Issued ※ 21 October 2023
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TUC3I2 Shaping High Brightness and Fixed Target Beams with the CERN PSB Charge Exchange Injection operation, emittance, target, brightness 135
 
  • C. Bracco, S.C.P. Albright, F. Asvesta, G.P. Di Giovanni, F. Roncarolo
    CERN, Meyrin, Switzerland
  
  CERN adopted the charge exchange injection technique for the first time in the PS Booster after Long Shutdown 2. This allowed to overcome space charge limitations, tailor high brightness beams for the LHC and deliver high intensity flux of protons to the fixed target experiments. Details on the concept, physics, hardware and diagnostic tools are presented while retracing the exciting steps of the successful commissioning period and the first years of operation with this system. A look to the future is taken by explaining the next stages to achieve the ambitious Luminosity targets foreseen for the HL-LHC era.  
slides icon Slides TUC3I2 [19.053 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC3I2  
About • Received ※ 01 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 24 October 2023
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TUC3I3 Laser Stripping of H⁻ Beam laser, experiment, proton, resonance 141
 
  • T.V. Gorlov, A.V. Aleksandrov, S.M. Cousineau, Y. Liu, A.R. Oguz
    ORNL, Oak Ridge, Tennessee, USA
  • N.J. Evans
    ORNL RAD, Oak Ridge, Tennessee, USA
  • P.K. Saha
    JAEA/J-PARC, Tokai-mura, Japan
  
  Basic principles of laser assisted charge exchange injection for H⁻ ion andH0 beams are presented. Theoretical aspects of electromagnetic interaction of laser with hydrogen atom and H⁻ ions are discussed. Laser excitation, photoionizatio and interaction of atoms and ions with a strong electro-magnetic field are discussed and compared. Different techniques of LACE for stripping of high current stochastic beams are presented. The optimum parameters of LACE are estimated and compared for various ion beam energies. Experimental development of laser stripping at the SNS are reviewed. Future plans of LACE at the SNS and J-PARC are discussed.  
slides icon Slides TUC3I3 [1.790 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC3I3  
About • Received ※ 04 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 01 November 2023
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TUA4I2 1-MW Beam Operation at J-PARC RCS with Minimum Beam Loss operation, simulation, beam-losses, scattering 147
 
  • P.K. Saha, H. Harada, H. Hotchi, K. Okabe, H. Okita, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yoshimoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  
  The 3-GeV RCS of J-PARC now operates at high-intensity to nearly the designed 1 MW beam. The beam loss and the corresponding residual radiation is one of the key limitations against beam intensity ramp up. Recently, by a series of beam studies and feedback from numerical simulations, we have well mitigated the beam loss to a minimum level and also reduced the beam emittances for beam operation to the spallation neutron source as well as to the main ring. The residual beam loss at the designed 1 MW beam power occurs mostly due to the unavoidable foil scattering beam loss during multi-turn injection, while other beam loss sources have been well mitigated to realize a stable and higher availability beam operation at a nearly 1 MW beam power.  
slides icon Slides TUA4I2 [2.303 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA4I2  
About • Received ※ 02 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 21 October 2023
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TUA4C2 Application of Programmable Trim Quadrupoles in Beam Commissioning of CSNS/RCS quadrupole, neutron, MMI, lattice 158
 
  • Y. Li, C.D. Deng, S.Y. Xu
    DNSC, Dongguan, People’s Republic of China
  • Y.W. An, X. Qi, S. Wang, Y.S. Yuan
    IHEP, Beijing, People’s Republic of China
  • H.Y. Liu
    IHEP CSNS, Guangdong Province, People’s Republic of China
  
  The China Spallation Neutron Source (CSNS) achieved its design power of 100 kW in 2020 and is currently stably operating at 140 kW after a series of measures. In the process of increasing beam power, 16 programmable trim quadrupoles were installed in the Rapid Cycling Synchrotron (RCS) of CSNS to enable rapid variation of tunes, effective adjustment of Twiss parameters, and restoration of lattice superperiodicity through the machine cycle. This paper provides a detailed introduction to the design of the trim quadrupoles and preliminary results of the machine study. The beam experiments show that the trim quadrupoles play a crucial role in increasing beam power after exceeding 100 kW.  
slides icon Slides TUA4C2 [4.136 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA4C2  
About • Received ※ 27 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 22 October 2023
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WEA1C1 Bunch-by-bunch Tune Shift Studies for LHC-type Beams in the CERN SPS simulation, impedance, wakefield, operation 194
 
  • I. Mases Solé, H. Bartosik, K. Paraschou, M. Schenk, C. Zannini
    CERN, Meyrin, Switzerland
  
  After the implementation of major upgrades as part of the LHC Injector Upgrade Project (LIU), the Super Proton Synchrotron (SPS) delivers high intensity bunch trains with 25 ns bunch spacing to the Large Hadron Collider (LHC). These beams are exposed to several collective effects in the SPS, such as beam coupling impedance, space charge and electron cloud, leading to relatively large bunch-by-bunch coherent and incoherent tune shifts. Tune correction to the nominal values at injection is crucial to ensure beam stability and good beam transmission. Measurements of the bunch-by-bunch coherent tune shifts have been performed under different beam conditions. In this paper, we present the measurements of the bunch-by-bunch tune shift as function of bunch intensity for trains of 72 bunches. The experimental data are compared to multiparticle tracking simulations (including other beam variants such as 8b4e beam and hybrid beams) using the SPS impedance model.  
slides icon Slides WEA1C1 [2.613 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA1C1  
About • Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 09 October 2023
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WEC3I1 Self-Consistent Injection Painting for Space Charge Mitigation space-charge, emittance, solenoid, experiment 258
 
  • N.J. Evans, V.S. Morozov
    ORNL RAD, Oak Ridge, Tennessee, USA
  • T.V. Gorlov, A.M. Hoover
    ORNL, Oak Ridge, Tennessee, USA
  
  Funding: This work was conducted at UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy, with partial funding provided by Field Work Proposal ORNL-ERKCS41.
I will present results of experiments at the Spallation Neutron Source to implement a method of phase space painting we refer to as ¿eigenpainting¿, in which beam is injected along one eigenvector of the transfer matrix of a ring with full coupling.  The method and resultant distribution were initially proposed by Danilov almost to linearize the space charge force, minimizing space charge tune spread. In the theoretically ideal case this so-called Danilov distribution has uniform charge distribution, elliptical envelope in real-space, and a vanishing 4D transverse emittance. Such a beam can be maintained throughout injection. The Danilov distribution has implications for increasing beam intensity beyond the conventional space charge limit through a reduction of both tune spread and shift, and increasing collider performance. This talk will present current limits on beam quality, and details of the preparation of the optics in the SNS accumulator ring, including the installation of new solenoid magnets. The status of experiments to improve beam quality and characterize the interesting dynamical implications of the defining features of the Danilov distribution will also be discussed. 		 
slides icon Slides WEC3I1 [2.687 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC3I1  
About • Received ※ 28 September 2023 — Revised ※ 10 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 23 October 2023
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WEC3I2 Mitigation of Space Charge Effects in RHIC and Its Injectors booster, space-charge, emittance, polarization 264
 
  • V. Schoefer, C.J. Gardner, K. Hock, H. Huang, K. Zeno
    BNL, Upton, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
The RHIC collider physics program, in particular its polarized proton and low energy heavy ion components, present unique challenges for maintaining collider performance in the presence of space charge effects. Polarized beam performance is especially sensitive to emittance increases, since they decrease both the luminosity and polarization. Operation of the collider with gold beams at sub-injection energies (down to 3.85 GeV/n Au) with space charge tune shifts up to 0.1 required special care to optimize both the ion lifetime and its interaction with the electron-beam cooler. We describe the operational experience in these modes and some of the mitigation efforts. 		 
slides icon Slides WEC3I2 [10.503 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC3I2  
About • Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 14 October 2023
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WEC3C1 Beyond 1-MW Scenario in J-Parc Rapid-Cycling Synchrotron cavity, acceleration, operation, linac 270
 
  • K. Yamamoto, T. Morishita, K. Moriya, H. Okita, P.K. Saha, Y. Shobuda, F. Tamura, I. Yamada, M. Yamamoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  
  The 3-GeV rapid cycling synchrotron at the Ja-pan Pro-ton Accelerator Research Complex was designed to provid 1-MW proton beams to the Material and Life Sci-ence Experimental Facility and Main Ring. Thanks to the improvement works of the accelerator system, we success-fully accelerate 1-MW beam with quite small beam loss. Currently, the beam power of RCS is limited by the lack of anode current in the RF cavity system rather than the beam loss. Recently we developed a new acceleration cavity that can accelerate a beam with less anode current. This new cavity enables us not only to reduce require-ment of the anode power supply but also to accelerate more than 1-MW beam. We have started to consider the way to achieve beyond 1-MW beam acceleration. So far, it is expected that up to 1.5-MW beam can be accelerated after replacement of the RF cavity. We have also contin-ued study to achieve more than 2 MW beam in J-PARC RCS.  
slides icon Slides WEC3C1 [2.787 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC3C1  
About • Received ※ 25 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 26 October 2023
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WEC3C3 Simulations and Measurements of Betatron and Off-momentum Cleaning Performance in the Energy Ramp at the LHC simulation, collimation, betatron, optics 279
 
  • N. Triantafyllou, R. Bruce, M. D’Andrea, K.A. Dewhurst, B. Lindström, D. Mirarchi, S. Redaelli, F.F. Van der Veken
    CERN, Meyrin, Switzerland
  
  The Large Hadron Collider (LHC) is equipped with a multistage collimation system that protects the machine against unavoidable beam losses at large betatron and energy offsets at all stages of operation. Dedicated validations and an understanding in simulations of the collimation performance are crucial for the energy ramp from 450 GeV to 6.8 TeV because complex changes of optics and orbit take place in this phase. Indeed, the betatron functions are reduced in all experiments for an efficient setup of the collisions at top energy. In this paper, simulations of the betatron and off-momentum cleaning during the energy ramp are presented. A particular focus is given to the off-momentum losses at the start of the ramp. The simulation results are benchmarked against experimental data, demonstrating the accuracy of the newly developed tools used for the simulations.  
slides icon Slides WEC3C3 [1.641 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC3C3  
About • Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 19 October 2023
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THA1I1 Performance and Upgrade Considerations for the CSNS Injection MMI, neutron, proton, simulation 326
 
  • M.Y. Huang, S. Wang, S.Y. Xu
    IHEP, Beijing, People’s Republic of China
  
  Funding: This work is jointly supported by the National Natural Science Foundation of China (Nos. 12075134) and the Guangdong Basic and Applied Basic Research Foundation (No. 2021B1515120021).
For the proton synchrotron, the beam injection is one of the most important issues. Firstly, based on the China Spallation Neutron Source (CSNS), the injection methods have been comprehensively studied, including phase space painting and H⁻ stripping. In order to solve the key difficulties faced when the beam power exceeds 50% of the design value, flexibility in the CSNS design has been exploited to implement the correlated painting by using the rising current curve of the pulse power supply. The effectiveness of the new method has been verified in the simulation and beam commissioning. By using the new method, the beam power on the target has successfully risen to the design value. Secondly, for the CSNS upgrade, the injection energy is increased from 80 MeV to 300 MeV and the injection beam power is increased by about 19 times. Based on the CSNS experience and simulation results, it is hoped that the new injection scheme can not only be compatible with correlated and anti-correlated painting, but also greatly reduces the peak temperature of the stripping foil. After in-depth study, a new painting scheme has been proposed which has been verified to be feasible in the simulation. 		 
slides icon Slides THA1I1 [2.951 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THA1I1  
About • Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 15 October 2023
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THAFP08 Performance of the Ion Chain at the CERN Injector Complex and Transmission Studies During the 2023 Slip Stacking Commissioning emittance, linac, MMI, extraction 418
 
  • M. Slupecki, S.C.P. Albright, R. Alemany-Fernández, M.E. Angoletta, T. Argyropoulos, H. Bartosik, P. Baudrenghien, G. Bellodi, M. Bozzolan, R. Bruce, C. Carli, J. Cenede, H. Damerau, A. Frassier, D. Gamba, G. Hagmann, A. Huschauer, V. Kain, G. Khatri, D. Küchler, A. Lasheen, K.S.B. Li, E. Mahner, G. Papotti, G. Piccinini, A. Rey, M. Schenk, R. Scrivens, A. Spierer, G. Tranquille, D. Valuch, F.M. Velotti, R. Wegner
    CERN, Meyrin, Switzerland
  • E. Waagaard
    EPFL, Lausanne, Switzerland
  
  The 2023 run has been decisive for the LHC Ion Injector Complex. It demonstrated the capability of producing full trains of momentum slip stacked lead ions in the SPS. Slip stacking is a technique of interleaving particle trains, reducing the bunch spacing in SPS from 100 ns to 50 ns. It is needed to reach the total ion intensity requested by the HL-LHC project, as defined by updated common LIU/HL-LHC target beam parameters. This paper reviews the lead beam characteristics across the Ion Injector Complex, including transmission efficiencies up to the SPS extraction. It also documents the difficulties found during the commissioning and the solutions put in place.  
slides icon Slides THAFP08 [1.114 MB]  
poster icon Poster THAFP08 [1.995 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP08  
About • Received ※ 01 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 21 October 2023
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THBP09 Pushing High Intensity and High Brightness Limits in the CERN PSB after the LIU Upgrades resonance, brightness, space-charge, emittance 458
 
  • F. Asvesta, S.C.P. Albright, H. Bartosik, C. Bracco, G.P. Di Giovanni, T. Prebibaj
    CERN, Meyrin, Switzerland
  
  After the successful completion of the LHC Injectors Upgrade (LIU) project, the CERN Proton Synchrotron Booster (PSB) has produced beams with up to two times higher brightness. However, the efforts to continuously improve the beam quality for the CERN physics experiments are ongoing. In particular, the high brightness LHC beams show non-Gaussian tails in the transverse profiles that can cause losses in the downstream machines, and even at LHC injection. As a result, alternative production schemes based on triple harmonic capture are being investigated in order to preserve brightness and reduce transverse tails at the same time. In addition, in view of a possible upgrade to the ISOLDE facility that would require approximately twice the number of protons per ring, the ultimate intensity reach of the PSB is explored. In this context, injection schemes using painting both transversely and longitudinally in order to mitigate the strong space charge effects are developed.  
poster icon Poster THBP09 [0.751 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP09  
About • Received ※ 28 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 20 October 2023
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THBP14 LHC Optics Measurements from Transverse Damper for the High Intensity Frontier dipole, optics, operation, resonance 479
 
  • T. Nissinen, F.S. Carlier, M. Le Garrec, E.H. Maclean, T.H.B. Persson, R. Tomás García, A. Wegscheider
    CERN, Meyrin, Switzerland
  
  Current and future accelerator projects are pushing the brightness and intensity frontier, creating new challenges for turn-by-turn based optics measurements. Transverse oscillations are limited in amplitude due to particle losses. The LHC Transverse Damper (ADT) is capable of generating low amplitude ac-dipole like transverse coherent beam oscillations. While the amplitude of such excitations is low, it is compensated by the excitation length of the ADT which, in theory, can last for up to 48h. Using the ADT, it is possible to use the maximum BPM acquisition length and improve the spectral resolution. First optics measurements have been performed using the ADT in the LHC in 2023, and the results are presented in this paper. Furthermore, some observed limitations of this method are presented and their impact on ADT studies are discussed.  
poster icon Poster THBP14 [2.632 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP14  
About • Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 25 October 2023
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THBP15 Optimizing Resonance Driving Terms Using MAD-NG Parametric Maps optics, resonance, octupole, emittance 483
 
  • L. Deniau, S. Kostoglou, E.H. Maclean, K. Paraschou, T.H.B. Persson, R. Tomás García
    CERN, Meyrin, Switzerland
  
  In 2023, a review of the LHC octupolar resonance driving terms at injection was carried out, motivated by two observations: (i) unwanted losses during the injection process with strongly powered octupoles and (ii) an expected reduction in emittance growth from e-cloud effects in simulations with weaker octupolar resonances. The MAD-NG code was used to simultaneously optimise the main octupolar resonances: 4Qx, 4Qy, and 2Qx-2Qy by adjusting 16 quadrupole families and 16 octupole families, for a total of 32 parameters. These knobs were introduced as parameters in the transfer map, allowing the Jacobian required by the optimiser to be calculated in a single pass, saving 32 additional optics evaluations and avoiding finite difference approximations. Constraints on tunes, amplitude detuning and optics around the machine were also considered as part of the optimisation process. This paper reviews the parametric optimisation with MAD-NG and compares the results with MADX-PTC.  
poster icon Poster THBP15 [0.938 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP15  
About • Received ※ 02 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 17 October 2023
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THBP20 Optics for Landau Damping with Minimized Octupolar Resonances in the LHC optics, resonance, octupole, focusing 503
 
  • R. Tomás García, F.S. Carlier, L. Deniau, J. Dilly, J. Keintzel, S. Kostoglou, M. Le Garrec, E.H. Maclean, K. Paraschou, T.H.B. Persson, F. Soubelet, A. Wegscheider
    CERN, Meyrin, Switzerland
  
  Operation of the Large Hadron Collider (LHC) requires strong octupolar magnetic fields to suppress coherent beam instabilities. The amplitude detuning that is generated by these octupolar magnetic fields brings the tune of individual particles close to harmful resonances, which are mostly driven by the octupolar fields themselves. In 2023, new optics were deployed in the LHC at injection with optimized betatronic phase advances to minimize the resonances from the octupolar fields without affecting the amplitude detuning. This paper reports on the optics design, commissioning and the lifetime measurements performed to validate the optics.  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP20  
About • Received ※ 01 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 23 October 2023
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THBP22 On Liouvillian High Power Beam Accumulation emittance, closed-orbit, accumulation, linac 511
 
  • J.-M. Lagniel
    GANIL, Caen, France
  • M.E. Eshraqi, N. Milas
    ESS, Lund, Sweden
  
  Funding: This work is co-funded by the European Union
It is acknowledged that the injection of high power proton beams into synchrotrons must be done using stripping injection of H⁻ beams which are accelerated by an injector, as done in many facilities worldwide such as ISIS, JPARC, SNS and CERN. However, this technique is not necessarily the only way of accumulation and in some cases might not represent the best choice. For example in the case of the ESSnuSB Accumulator Ring, accelerating the protons injecting them to the ring could represent savings in capital cost, reduced risk of losses in the linac and transfer lines and simplification to the overall project. This work presents the development of a method allowing to optimize the 4D Liouvillian accumulation of high-power proton and heavy ion beams and finishes with a discussion on the pros and cons of proton injection compared to more traditional H⁻ stripping injection method. 		 
poster icon Poster THBP22 [2.126 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP22  
About • Received ※ 01 October 2023 — Revised ※ 05 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 28 October 2023
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THBP23 Exploring Space Charge and Intra-beam Scattering Effects in the CERN Ion Injector Chain space-charge, emittance, scattering, operation 515
 
  • E. Waagaard
    EPFL, Lausanne, Switzerland
  • H. Bartosik
    CERN, Meyrin, Switzerland
  
  As of today, the LHC ion physics programme is mostly based on Pb ion collisions. The ALICE3 detector proposal requests significantly higher nucleon-nucleon luminosities, as compared to today¿s operation. This improved performance could be potentially achieved with lighter ion species than Pb. In this respect, the CERN Ion Injector chain (consisting of Linac3, LEIR, PS and SPS) will need to provide significantly higher beam intensities with light ion beams as compared to the present ones, whereas operational experience with such beams is limited. We present space charge and intra-beam scattering studies across the Ion Injector chain and strategies to build benchmarked simulation models for optimised ion performance. This is the first step for identifying the ideal ion isotopes and charge states for maximised LHC luminosity production.  
poster icon Poster THBP23 [2.744 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP23  
About • Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 24 October 2023
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THBP24 RCS and Accumulator Rings Designs for ISIS II space-charge, proton, emittance, lattice 519
 
  • D.J. Adams
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  • H.V. Cavanagh, I.S.K. Gardner, B.S. Kyle, H. Rafique, C.M. Warsop, R.E. Williamson
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  
  ISIS is the spallation neutron source at the Rutherford Appleton Laboratory in the UK, which provides 0.2 MW of beam power via a 50 Hz, 800 MeV proton RCS. Detailed studies are now underway to find the optimal configuration for a next generation, short-pulsed neutron source that will define a major ISIS upgrade, with construction beginning ~2031. Determining the optimal specification for such a facility is the subject of an ongoing study involving neutron users, target and instrument experts. The accelerator designs being considered for the MW beam powers required, include proposals exploiting FFA rings as well as conventional accumulator and RCS rings. This paper summarises work on physics designs for the conventional rings. Details of lattice designs, injection and extraction systems, correction systems as well as detailed 3D PIC simulations used to ensure 0.1% losses and low foil hits are presented. Designs for a 0.4 to 1.2 GeV RCS and 1.2 GeV AR are outlined. Work on the next stages of the study are also summarised to benchmark and minimise predicted losses, and thus maximise the high intensity limit of designs.  
poster icon Poster THBP24 [3.231 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP24  
About • Received ※ 28 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 22 October 2023
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THBP28 A Phase Trombone for the Fermilab PIP-II Beam Transfer Line booster, lattice, linac, collimation 527
 
  • M. Xiao, D.E. Johnson, J.-F. Ostiguy
    Fermilab, Batavia, Illinois, USA
  
  The PIP-II beam transfer line (BTL) transports the beam from the PIP-II Linac to the Booster synchrotron ring. A crucial aspect of the BTL design is the collimation system which play a vital role in removing large ampli-tude particles that may otherwise miss the horizontal and vertical edges of the foil at the point of injection into the Booster. To ensure the effectiveness of the collimators, simulations were conducted to determine optimal place-ment within the BTL. These simulations revealed that precise control of the accumulated phase advances be-tween the collimators and the foil is critical. To achieve fine-tuning of the phase advance, a phase trombone was incorporated within the BTL. This paper presents the design and implementation details of this phase trom-bone  
poster icon Poster THBP28 [0.798 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP28  
About • Received ※ 20 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 30 October 2023
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THBP29 Effects of Cavity Pre-Detuning on RF Power Transients at Injection into the LHC cavity, simulation, operation, controls 530
 
  • B.E. Karlsen-Bæck, T. Argyropoulos, A.C. Butterworth, R. Calaga, I. Karpov, H. Timko, M. Zampetakis
    CERN, Meyrin, Switzerland
  
  At injection into the LHC, the RF system is perturbed by beam-induced voltage resulting in strong RF power transients and the instant detuning of the cavities. The automatic tuning system, however, needs time for the mechanical compensation of the resonance frequency to take place. Acting back on the beam, the transients in RF power are expected to limit the maximum injected intensity by generating unacceptable beam loss. Reducing them is therefore essential to reach the target intensity during the High Luminosity (HL) LHC era. At LHC flat bottom, the cavities are operated using the half-detuning beam-loading compensation scheme. As implemented today, the tuner control algorithm starts acting only after the injection of the first longer bunch train which causes the bunches for this injection to experience the largest power spikes. This contribution presents an adapted detuning scheme for the RF cavities before injection. It was proposed as a path to decrease the transients, hence increasing the available intensity margin for the available RF power. The expected gain is evaluated in particle tracking simulations and measurements acquired during operation.  
poster icon Poster THBP29 [3.711 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP29  
About • Received ※ 30 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 22 October 2023
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THBP31 Electron Cloud Effects in the CERN Accelerators in Run 3 electron, operation, kicker, simulation 538
 
  • L. Mether, H. Bartosik, L. Giacomel, G. Iadarola, S. Johannesson, I. Mases Solé, K. Paraschou, G. Rumolo, L. Sabato, C. Zannini, E. de la Fuente
    CERN, Meyrin, Switzerland
  • S. Johannesson
    EPFL, Lausanne, Switzerland
  
  Several of the machines in the CERN accelerator complex, in particular the Large Hadron Collider (LHC) and the Super Proton Synchrotron (SPS), are prone to the build-up of electron clouds. Electron cloud effects are observed especially when the machines are operated with a 25 ns bunch spacing, which has routinely been used in the LHC since the start of its second operational run in 2015. After the completion of the LHC Injectors Upgrade program during the latest long shutdown period, the machines are currently operated with unprecedented bunch intensity and beam brightness. With the increase in bunch intensity, electron cloud effects have become one of the main performance limitations, as predicted by simulation studies. In this contribution we present the experimental observations of electron cloud effects since 2021 and discuss their implications for the future operation of the complex.  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP31  
About • Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 23 October 2023
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THBP37 Refining the LHC Longitudinal Impedance Model impedance, cavity, simulation, damping 559
 
  • M. Zampetakis, T. Argyropoulos, Y. Brischetto, R. Calaga, L. Giacomel, B.E. Karlsen-Bæck, I. Karpov, I. Karpov, N. Mounet, B. Salvant, H. Timko
    CERN, GENEVA, Switzerland
  • B.E. Karlsen-Bæck
    INFN-Roma, Roma, Italy
  
  Modelling the longitudinal impedance for the Large Hadron Collider (LHC) has been a long-standing effort, especially in view of its High-Luminosity (HL) upgrade. The resulting impedance model is an essential input for beam dynamics studies. Increased beam intensities in the HL-LHC era will pose new challenges like RF power limitations, beam losses at injection and coupled-bunch instabilities throughout the acceleration cycle. Starting from the existing longitudinal impedance model, effort has been made to identify the main contributing devices and improve their modelling. Loss of Landau damping (LLD) simulations are performed to investigate the dependence of the stability threshold on the completeness of the impedance model and its broad-band cut-off frequency. Plans to perform beam measurements to estimate the cut-off frequency, by investigating the LLD threshold in operation, are also discussed.  
poster icon Poster THBP37 [5.606 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP37  
About • Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 14 October 2023
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THBP38 Two-Dimensional Longitudinal Painting at Injection into the CERN PS Booster linac, target, synchrotron, emittance 563
 
  • S.C.P. Albright, F. Asvesta, B. Bielawski, C. Bracco, P.K. Skowroński, R. Wegner
    CERN, Meyrin, Switzerland
  
  To inject highest beam intensities at the transfer from Linac4 into the four rings of the PS Booster (PSB) at CERN, protons must be accumulated during up to 148 turns in total. With the conventional, fixed chopping pattern this process results in an approximately rectangular distribution in the longitudinal phase space. As the bucket shape in the PSB does not correspond to this distribution, the process leads to longitudinal mismatch, contributing to emittance growth and reduced transmission. The field in the last accelerating cavity of Linac4 can be modulated, which leads to fine corrections of the extracted beam energy. At the same time, the chopping pattern can be varied. Combining both allows injecting a near uniform longitudinal distribution whose boundary corresponds to an iso-Hamiltonian contour of the RF bucket, hence significantly reducing mismatch. In an operational context, the longitudinal painting must be controlled in a way that allows easy intensity variation, and can even require different painting configurations for each of the four PSB rings. This contribution presents the first demonstration of longitudinal painting in the PSB, and its impact on beam performance.  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP38  
About • Received ※ 30 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 24 October 2023
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THBP39 Advances on LHC RF Power Limitation Studies at Injection cavity, operation, klystron, controls 567
 
  • H. Timko, T. Argyropoulos, R. Calaga, N. Catalán Lasheras, K. Iliakis, B.E. Karlsen-Bæck, I. Karpov, M. Zampetakis
    CERN, Meyrin, Switzerland
  
  The average power consumption of the main RF system during beam injection in the High-Luminosity Large Hadron Collider is expected to be close to the maximum available klystron power. Power transients due to the mismatch of the beam and the action of control loops will exceed the available power. This paper presents the most recent estimations of the injection voltage and steady-state power needed for HL-LHC intensities, taking also beam stability into account. It summarises measurement and simulation efforts ongoing to better understand power transients and beam losses, and describes the operational margin to be taken into account for different equipment.  
poster icon Poster THBP39 [0.861 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP39  
About • Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 20 October 2023
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THBP45 Longitudinal Collective Effects at Beam Transfer from PS to SPS at CERN simulation, beam-loading, impedance, cavity 587
 
  • A. Lasheen, H. Damerau, I. Karpov, G. Papotti, E.T. Vinten
    CERN, Meyrin, Switzerland
  
  The hardware upgrades of the LHC Injectors Upgrade (LIU) project at CERN were completed during the Long Shutdown 2 (2019-2021) to prepare the injectors for the beams required by the High Luminosity (HL) LHC. Doubling the bunch intensity leads to new challenges due to collective effects. Although many bottlenecks were already solved, a remaining limitation is the important loss of particles at transfer from the Proton Synchrotron (PS) to the Super Proton Synchrotron (SPS). The maximum transmission achieved since the restart in 2021 is in the order of 90%, yet leading to unnecessary activation of the SPS. The losses are distributed at various instants of the SPS cycle: fast intensity decay right after injection, slow losses along the injection plateau while waiting for multiple injections from the PS, and uncaptured beam removed at start of acceleration. In this contribution, the focus is on longitudinal aspects of transfer losses and more specifically on intensity effects during the non-adiabatic bunch shorting performed in the PS prior to extraction, as well as on the longitudinal mismatch at injection due to misaligned bunch phases in the SPS caused by transient beam loading.  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP45  
About • Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 15 October 2023
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THBP55 Commissioning of NICA Injection Complex booster, electron, acceleration, operation 618
 
  • V.A. Lebedev, O.I. Brovko, A.V. Butenko, E.E. Donets, B.V. Golovenskiy, E.V. Gorbachev, S.A. Kostromin, K.A. Levterov, I.N. Meshkov, A.S. Sergeev, M.M. Shandov, A.O. Sidorin, V.L. Smirnov, E. Syresin, A. Tuzikov
    JINR, Dubna, Moscow Region, Russia
  • I. Nikolaichuk, A.Yu. Ramsdorf
    JINR/VBLHEP, Dubna, Moscow region, Russia
  
  The Nuclotron-based Ion Collider fAcility (NICA) is under construction at JINR. The NICA project goal is to provide colliding beams for studies of collisions of heavy fully stripped ions and light p¿lairized ions. The NICA Collider includes two rings with 503 m circumference each and the injection complex. For the heavy ion mode, the injection complex consists of following accelerators: 3.2 MeV/u linac (HILAC), 600 MeV/u (A/Z=6) superconducting booster synchrotron (Booster) and main superconducting synchrotron (Nuclotron) with kinetic energy up to 3.9 GeV/u (A/Z=2.5). The injection complex has been under commissioning for more than 2 years. Its Run IV was carried from October 2022 to February of 2023. It was aimed on the injection complex preparation for the collider operations in the heavy ion mode. Additionally, the slowly extracted 3.9 GeV/u xenon beam was delivered to the BM&N experiment resulting in 250 million events in the detector. The paper discusses main results of the injection complex commissioning and plans for its further development. The beam commissioning of the collider is expected in the 2nd half of 2025.  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP55  
About • Received ※ 26 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 17 October 2023
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FRA1I2 Design and Beam Commissioning of Dual Harmonic RF System in CSNS RCS cavity, bunching, MMI, space-charge 633
 
  • H.Y. Liu, L. Huang
    IHEP CSNS, Guangdong Province, People’s Republic of China
  • Y. Liu
    DNSC, Dongguan, People’s Republic of China
  • S. Wang, S.Y. Xu
    IHEP, Beijing, People’s Republic of China
  
  The CSNS accelerator achieved an average beam power on target of 100 kW in February 2020 and subsequently increased it to 125 kW in March 2022. Building upon this success, CSNS plans to further enhance the average beam power to 200 kW by doubling the particle number of the circulating beam in the RCS, while keeping the injection energy same. The space charge effect is a main limit for the beam intensity increase in high-power particle accelerators. By providing a second harmonic RF cavity with a harmonic number of 4, in combination with the ferrite cavity with a harmonic number of 2, the dual harmonic RF system aims to mitigate emittance increase and beam loss caused by space charge effects, thereby optimizing the longitudinal beam distribution. This paper will concentrate on the beam commissioning for the 140 kW operation subsequent to the installation of the magnetic alloy (MA) cavity. The commissioning process includes the optimization of RF parameters, beam studies, and evaluation of the beam quality and instability.  
slides icon Slides FRA1I2 [4.086 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-FRA1I2  
About • Received ※ 30 September 2023 — Revised ※ 09 October 2023 — Accepted ※ 14 October 2023 — Issued ※ 27 October 2023
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FRA2I3 Summary of the Working Group C on Accelerator Systems impedance, cavity, target, laser 670
 
  • S. Machida
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • H. Huang
    BNL, Upton, New York, USA
  • P.K. Saha
    JAEA/J-PARC, Tokai-mura, Japan
  
  This is a summary of the presentations and discussions of the Accelerator System working group at the 68th ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams.  
slides icon Slides FRA2I3 [0.262 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-FRA2I3  
About • Received ※ 22 November 2023 — Accepted ※ 29 November 2023 — Issued ※ 15 December 2023  
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