MOPOST —  Poster Session - Somtam   (13-Jun-22   14:00—16:00)
Paper Title Page
MOPOST001 Performance of Automated Synchrotron Lattice Optimisation Using Genetic Algorithm 38
SUSPMF042   use link to see paper's listing under its alternate paper code  
 
  • X. Zhang, S.L. Sheehy
    The University of Melbourne, Melbourne, Victoria, Australia
  • S.L. Sheehy
    ANSTO, Kirrawee DC New South Wales, Australia
 
  Funding: Work supported by Australian Government Research Training Program Scholarship
Rapid advances in superconducting magnets and related accelerator technology opens many unexplored possibilities for future synchrotron designs. We present an efficient method to probe the feasible parameter space of synchrotron lattice configurations. Using this method, we can converge on a suite of optimal solutions with multiple optimisation objectives. It is a general method that can be adapted to other lattice design problems with different constraints or optimisation objectives. In this method, we tackle the lattice design problem using a multi-objective genetic algorithm. The problem is encoded by representing the components of each lattice as columns of a matrix. This new method is an improvement over the neural network based approach* in terms of computational resources. We evaluate the performance and limitations of this new method with benchmark results.
*Conference Proceedings IPAC’21, 2021. DOI:10.18429/JACoW-IPAC2021-MOPAB182
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST001  
About • Received ※ 19 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 17 June 2022
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MOPOST003 BBQ and Doughnut Beams: A Tasty Recipe for Measuring Amplitude Dependence of the Closest Tune Approach 42
 
  • E.H. Maclean, F.S. Carlier, T.H.B. Persson, R. Tomás García
    CERN, Meyrin, Switzerland
 
  Beam-based observations and theoretical studies have demonstrated the existence of a significant amplitude dependence of the closest tune approach (ADECTA) in the LHC. This effect has the potential to generate significant distortion of the tune footprint and thus is of interest in regard to Landau damping. Conventionally ADECTA has been studied through saturation of tune separation with action during amplitude-detuning type measurements. In this paper, an alternative measurement technique is proposed and results of initial tests with beam are presented. The novel technique attempts to measure ADECTA by performing a classical closest approach tune scan, using proton beams in the LHC, which have been kicked and allowed to decohere, effectively giving a large action doughnut beam. It is shown that the tune and closest approach of the doughnut beams can be measured using the existing LHC Base-Band tune (BBQ) measurement system, and an amplitude dependence can be observed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST003  
About • Received ※ 08 June 2022 — Revised ※ 20 June 2022 — Accepted ※ 12 July 2022 — Issue date ※ 22 June 2022
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MOPOST004 Beam-Based Measurement of Skew-Sextupole Errors in the CERN Proton Synchrotron 46
 
  • S.J. Horney, A. Huschauer, E.H. Macleanpresenter
    CERN, Meyrin, Switzerland
 
  During Proton Synchrotron (PS) commissioning in 2021, large beam losses were observed when crossing the 3Qy resonance if the Beam Gas Ionization (BGI) profile monitor was enabled. This indicated the presence of a strong skew-sextupole source in this instrument. Beam-based measurements of the skew sextupole component in the BGI magnet were performed, in order to benchmark the BGI magnetic model and to provide quantitative checks of sextupole corrections determined empirically to minimize the beam-losses. In this contribution, results of the successfully performed measurements are presented, including tune feed-down, chromatic coupling and resonance driving terms.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST004  
About • Received ※ 08 June 2022 — Revised ※ 18 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 23 June 2022
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MOPOST005 The HL-LHC Project Gets Ready for Its Deployment 50
 
  • M. Zerlauth, O.S. Brüning, B. Di Girolamo, P. Fessia, C. Gaignant, H. Garcia Gavela, E.H. Macleanpresenter, M. Modena, Th. Otto, L.J. Tavian, G. Vandoni
    CERN, Meyrin, Switzerland
 
  Following the successful completion of the second long shutdown (LS2), the Large Hadron Collider (LHC) is preparing for its final operational run before the majority of the High Luminosity Upgrade (HL-LHC) will be installed during the third Long Shutdown starting in 2026. The HL-LHC upgrade will enable a further tenfold increase in integrated luminosity delivered to the ATLAS and CMS experiments, starting by an upgrade of the machine protection, collimation and shielding systems in LS2, and followed by the deployment of novel key technologies, including Nb3Sn based insertion region magnets, cold powering by MgB2 superconducting links and integration of Nb crab-cavities to compensate the effects of a larger crossing angle. After a period of intensive R&D and prototyping, the project is now entering the phase of industrialization and series production for all main components. In this contribution, we provide an overview of the project status and plans for deployment and performance ramp-up. Progress on the validation of key technologies, status of prototypes and series production as well as the final integration studies for the HL equipment are summarized. These are accompanied by the imminent completion of major civil engineering work and the start of infrastructure installations. Initial operational experience will be gained at the Inner Triplet (IT) String, presently in assembly at CERN’s Superconducting Magnet Test Facility, which will enable a fully integrated test of the main magnets, powering, and protection systems in the actual HL-LHC insertion configuration.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST005  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 18 June 2022
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MOPOST006 Beam Commissioning and Optimisation in the CERN Proton Synchrotron After the Upgrade of the LHC Injectors 54
 
  • A. Huschauer, M.R. Coly, D.G. Cotte, H. Damerau, M. Delrieux, J.-C. Dumont, Y. Dutheil, S.E.R. Easton, M.A. Fraser, O. Hans, G.I. Imesch, S. Joly, A. Lasheen, C.L. Lombard, R. Maillet, B. Mikulec, J.-M. Nonglaton, S. Sainz Perez, B. Salvant, R. Suykerbuyk, F. Tecker, R. Valera Teruel
    CERN, Meyrin, Switzerland
 
  The CERN LHC injector chain underwent a major upgrade during the Long Shutdown 2 (LS2) in the framework of the LHC Injectors Upgrade (LIU) project. After 2 years of installation work, the Proton Synchrotron (PS) was restarted in 2021 with the goal to achieve pre-LS2 beam quality by the end of 2021. This contribution details the main beam commissioning milestones, encountered difficulties and lessons learned. The status of the fixed-target and LHC beams will be given and improvements in terms of performance, controls and tools described.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST006  
About • Received ※ 01 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 02 July 2022
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MOPOST007 Summary of the First Fully Operational Run of LINAC4 at CERN 58
 
  • P.K. Skowroński, G. Bellodi, B. Bielawski, R.B. Borner, G.P. Di Giovanni, E. Gousiou, J.-B. Lallement, A.M. Lombardi, B. Mikulec, J. Parra-Lopez, F. Roncarolo, J.L. Sanchez Alvarez, R. Scrivens, L. Timeo, R. Wegner
    CERN, Meyrin, Switzerland
 
  In December 2020 the newly commissioned LINAC4 started delivering beam for the CERN proton accelerator chain, replacing the old LINAC2. LINAC4 is a 352 MHz normal conducting linac, providing a beam of negative hydrogen ions at 160 MeV that are converted into protons at injection into the PS Booster synchrotron. In this paper we report on the achieved beam performance, availability, reproducibility and other operational aspects of LINAC4 during its first fully operational year. We also present the machine developments performed and the plans for future improvements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST007  
About • Received ※ 09 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 04 July 2022
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MOPOST008 Simulations of Protons to Extraction at Gγ=7.5 in the AGS Booster 62
 
  • K. Hock, H. Huang, F. Méot
    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.
To prepare for polarized helion collisions at the Electron Ion Collider (EIC), polarization transmission at the injectors for the Hadron Storage Ring must be studied and optimized. To this effect, an AC dipole has been installed in the AGS Booster to maximize polarization transmission of helions through several intrinsic resonances. This installation also allows polarized protons to be extracted at higher energy without polarization loss. By increasing the proton extraction energy from $Gγ$ = 4.5 to $Gγ$ = 7.5, protons will cross the $Gγ$ = 0 + νy$ and $Gγ = 12 - νy$ depolarizing vertical intrinsic resonances, the $Gγ$ = 5, 6, and 7 imperfection resonances in addition to the $Gγ$ = 3, 4 that are crossed in the present configuration, and be injected into the AGS at a higher rigidity. By simulation, it is determined that there is sufficient strength of the AC dipole to fully flip the spin spin through each of the intrinsic resonances, and there is sufficient corrector current to preserve polarization through the three additional imperfection resonances. The higher injection rigidity facilitates the horizontal and vertical tunes being placed inside the AGS spin-tune gap at injection due to a substantial improvement on the AGS admittance at injection.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST008  
About • Received ※ 06 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
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MOPOST009 EIC Crab Cavity Multipole Analysis and Their Effects on Dynamic Aperture 66
 
  • Q. Wu, B.P. Xiao
    BNL, Upton, New York, USA
  • S.U. De Silva
    ODU, Norfolk, Virginia, USA
  • Z. Li
    SLAC, Menlo Park, California, USA
  • Y. Luopresenter
    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.
Crab cavity is essential for retrieving the loss in luminosity due to the large crossing angle in the two colliding beam lines of the Electron Ion Collider (EIC). Due to the asymmetric design of the proton beam crab cavity, the fundamental mode consists of contributions from higher order multipoles. These multipole modes may change during fabrication and installation of the cavities, and therefore affect the local dynamic aperture. Thresholds for each order of the multipoles are applied to ensure dynamic aperture requirements at these crab cavities. In this paper, we analyzed the strength of the multipoles due to fabrication and installation accuracies, and set limitations to each procedure to maintain the dynamic aperture requirement.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST009  
About • Received ※ 06 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 10 July 2022
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MOPOST010 Deuteron Beam Power Ramp-Up at SPIRAL2 70
 
  • A.K. Orduz, M. Di Giacomo, R. Ferdinand, J.-M. Lagniel, G. Normand
    GANIL, Caen, France
  • D.U. Uriot
    CEA-IRFU, Gif-sur-Yvette, France
 
  The SPIRAL2 linac commissioning started on 8 July 2019 after obtaining the authorisation to operate by the French Safety Authority. The tuning of the two Low Energy Beam Transport (LEBT), Radio Frequency Quadrupole (RFQ), Medium Energy Beam Transport (MEBT), Superconducting (SC) linac and High Energy Beam Transport (HEBT) was done with H+, 4He2+ and D+ beams during three periods of six months each in 2019, 2020 and 2021. The results obtained in 2021 with a D+ beam are presented. The strategy for the tuning of the MEBT, including three rebunchers, is described. The comparison between the beam parameter measurements and reference simulations are also presented. The main results of the power ramp-up to 10 kW in the linac with a 5 mA D+ beam are next reported. Finally, the extrapolation from the nominal power (200 kW) to the obtained results is analysed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST010  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 18 June 2022
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MOPOST011 CEA Contribution to the PIP-II Linear Accelerator 74
 
  • N. Bazin, J. Belorgey, S. Berry, J. Drant, O. Napoly, A. Raut, P. Sahuquet, C. Simon
    CEA-DRF-IRFU, France
  • S. Arsenyev, Q. Bertrand, P. Brédy, E. Cenni, C. Cloué, R. Cubizolles, H. Jenhani, S. Ladegaillerie, A. Le Baut, A. Moreau, O. Piquet
    CEA-IRFU, Gif-sur-Yvette, France
  • O. Napoly
    Fermilab, Batavia, Illinois, USA
 
  The Proton Improvement Plan II (PIP-II) that will be installed at Fermilab is the first U.S. accelerator project that will have significant contributions from international partners. CEA joined the international collaboration in 2018, and will deliver 10 low-beta cryomodules as In-Kind Contribution to the PIP-II project, with cavities supplied by LASA-INFN and power couplers and tuning systems supplied by Fermilab. This paper presents the CEA scope of work that includes the design, manufacturing, assembly and tests of the cryomodules and the upgrade of the existing infrastructures to the PIP-II requirements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST011  
About • Received ※ 13 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 25 June 2022
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MOPOST012 High Current Heavy Ion Beam Investigations at GSI-UNILAC 78
 
  • H. Vormann, W.A. Barth, M. Miski-Oglu, U. Scheeler, M. Vossbergpresenter, S. Yaramyshev
    GSI, Darmstadt, Germany
  • W.A. Barth, M. Miski-Oglu, S. Yaramyshev
    HIM, Mainz, Germany
 
  The GSI Universal Linear Accelerator UNILAC and the synchrotron SIS18 will serve as injector for the upcoming FAIR-facility. The UNILAC-High Current Injector will be improved and modernized until FAIR is commissioned and the Alvarez poststripper accelerator is replaced. The reference heavy ion for future FAIR-operation is uranium, with highest intensity requirements. To re-establish uranium beam operation and to improve high current beam operation, different subjects have been explored in dedicated machine investigation campaigns. After a beam line modification in 2017 the RFQ-performance had deteriorated significantly; new rods have been installed and the RF-working point has been redefined. Also the Superlens-performance had become unsatisfactory; improved with a modified RF-coupler. With a pulsed hydrogen gas stripper target the uranium beam stripping efficiency could be increased by 65%. Various work has already been carried out to establish this stripper device in routine operation. With medium heavy ion beams a very high beam brilliance at the end of transfer line to SIS18 was achieved. Results of the measurement campaigns and the UNILAC upgrade activities will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST012  
About • Received ※ 19 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 02 July 2022
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MOPOST014 The 325 MHz FAIR pLinac Ladder RFQ - Final Assembly for Commissioning 82
 
  • M. Schuett, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  • C.M. Kleffner, K. Knie
    GSI, Darmstadt, Germany
 
  Based on the positive results of the unmodulated 325 MHz Ladder-RFQ prototype from 2013 to 2016, we developed and designed a modulated 3.4 m Ladder-RFQ*. The Ladder-RFQ features a very constant voltage along the axis as well as low dipole modes. The unmodulated prototype accepted 3 times the operating power of which is needed in operation** corresponding to a Kilpatrick factor of 3.1 with a pulse length of 200 µs. The 325 MHz RFQ is designed to accelerate protons from 95 keV to 3.0 MeV according to the design parameters of the proton linac within the FAIR project***. This particular high frequency for a 4-ROD-RFQ creates difficulties, which triggered the development of a Ladder-RFQ with its high symmetry. The results of the unmodulated prototype have shown, that the Ladder-RFQ is very well suited for that frequency. For the applied cooling concept, the Ladder-RFQ can be driven up to a duty factor of 10%. Manufacturing has been completed in September 2018. The final flatness & frequency tuning as well as the final assembly have been completed. We present the final RF measurements and assembly steps getting the Ladder-RFQ ready for shipment and high power RF test prior to assembly.
*Journal of Physics: Conf. Series 874 (2017) 012048
**Proceedings of LINAC2016, East Lansing, TUPLR053
***Proceedings of LINAC20118, pp.787-789
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST014  
About • Received ※ 12 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 05 July 2022
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MOPOST015 Beam Dynamics Simulations for the Superconducting HELIAC CW Linac at GSI 86
 
  • M. Schwarz, T. Conrad, H. Podlech
    IAP, Frankfurt am Main, Germany
  • K. Aulenbacher, F.D. Dziuba, S. Lauber, J. List
    IKP, Mainz, Germany
  • K. Aulenbacher, W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu, S. Yaramyshev
    HIM, Mainz, Germany
  • K. Aulenbacher, W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, V. Gettmann, M. Heilmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu, A. Rubin, S. Yaramyshev
    GSI, Darmstadt, Germany
  • W.A. Barth
    KPH, Mainz, Germany
  • H. Podlech
    HFHF, Frankfurt am Main, Germany
 
  Funding: Work supported by the German Federal Ministry of Education and Research (BMBF, contract no. 05P21RFRB2)
The superconducting (SC) continuous wave (CW) heavy ion linac HELIAC (HElm\-holtz LInear ACcelerator) is a common project of GSI and HIM under key support of IAP Frankfurt. It is intended for future experiments with heavy ions near the Coulomb barrier within super-heavy element (SHE) research and aims at developing a linac with multiple CH cavities as key components downstream the High Charge State Injector (HLI) at GSI. The design is challenging due to the requirement of intense beams in CW mode up to a mass-to-charge ratio of 6, while covering a broad output energy range from 3.5 to 7.3 MeV/u with minimum energy spread. In 2017 the first superconducting cavity of the linac has been successfully commissioned and extensively tested with beam at GSI. In the light of experience gained in this research so far, the beam dynamics layout for the entire linac has been updated and optimized in the meantime. This contribution will provide a brief overview of the recent progress on the project, as well as a potential modification to the linac layout.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST015  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 03 July 2022 — Issue date ※ 10 July 2022
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MOPOST016 Proton Linac Design for the High Brilliance Neutron Source HBS 90
 
  • M. Schwarz, M. Droba, K. Kümpel, S. Lamprecht, O. Meusel, N.F. Petry, H. Podlech
    IAP, Frankfurt am Main, Germany
  • J. Baggemann, Th. Brückel, T. Gutberlet, E. Mauerhofer, U. Rücker, A. Schwab, P. Zakalek
    JCNS, Jülich, Germany
  • J. Li
    IEK, Jülich, Germany
  • C. Zhang
    GSI, Darmstadt, Germany
 
  Due to the decommissioning of several reactors, only about half of the neutrons will be available for research in Europe in the next decade despite the commissioning of the ESS. High-Current Accelerator-driven Neutron Sources (HiCANS) could fill this gap. The High Brilliance Neutron Source (HBS) currently under development at Forschungszentrum Jülich is scalable in terms of beam energy and power due to its modular design. The driver linac will accelerate a 100 mA proton beam to 70 MeV. The linac is operated with a beam duty cycle of up to 13.6 % (15.3 % RF duty cycle) and can simultaneously deliver three pulse lengths (208 µs, 833 µs and 2 ms) for three neutron target stations. In order to minimize the development effort and the technological risk, state-of-the-art technology of the MYRRHA injector is used. The HBS linac consists of a front end (ECR source, LEBT, 2.5 MeV double RFQ) and a CH-DTL section with 44 room temperature CH-cavities. All RF structures are operated at 176.1 MHz and are designed for high duty cycle. Solid-state amplifiers up to 500 kW are used as RF drivers. Due to the beam current and the high average beam power of up to 952 kW, particular attention is paid to beam dynamics. In order to minimize beam losses, a quasi-periodic lattice with constant negative phase is used. This paper describes the conceptual design and the challenges of a modern high-power and high-current proton accelerator with high reliability and availability.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST016  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 11 July 2022
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MOPOST017 Design and Beam Dynamics Study of Disk-Loaded Structure for Muon Linac 94
 
  • K. Sumi, T. Iijima, K. Inami, Y. Sue, M. Yotsuzuka
    Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
  • H. Ego, T. Mibe, N. Saito, M. Yoshida
    KEK, Ibaraki, Japan
  • T. Iijima
    KMI, Nagoya, AIchi Prefecture, Japan
  • Y. Kondo, K. Moriya
    JAEA/J-PARC, Tokai-mura, Japan
  • Y. Nakazawa
    Ibaraki University, Hitachi, Ibaraki, Japan
  • M. Otani
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • Y. Takeuchi
    Kyushu University, Fukuoka, Japan
  • H.Y. Yasuda
    University of Tokyo, Tokyo, Japan
 
  The disk-loaded structures (DLS) in the muon LINAC are under development for the J-PARC muon g-2/EDM experiment. Four DLSs with an accelerating gradient of 20 MV/m take charge of muon acceleration from 40 MeV to 212 MeV, which corresponds to 70% to 94% of the speed of light. The quasi-constant gradient type TM01-2pi/3 mode DLSs with gradually varying disk spacing was designed and confirmed that the cumulative phase slip due to the mismatch between muon and phase velocity can be suppressed to less than 2 degrees at the frequency of 2592 MHz. In addition, the optimum synchronous phase and the lattice were investigated to satisfy the requirements of the total emittance less than 1.5 pi mm mrad and the momentum spread less than 0.1% in RMS.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST017  
About • Received ※ 19 May 2022 — Revised ※ 09 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022
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MOPOST020 In-Kind Contributions: The PIP-II Project at Fermilab 98
 
  • L. Lari, L. Merminga, A.M. Rowe
    Fermilab, Batavia, Illinois, USA
 
  Funding: Work supported, in part, by the U.S. Department of Energy, Office of Science, Office of High Energy Physics, under U.S. DOE Contract No. DE-AC02-07CH11359.
The Proton Improvement Plan II (PIP-II) Project is the first U.S. accelerator project that has significant contributions from international partners. A project management framework was created to fully integrate and make consistent across all partners the design, development, and delivery of In-Kind Contributions (IKC) into PIP-II. This framework consists of planning documentation, procedures, and communication and assessment processes to control schedule, risk, quality, and technical integration over the lifetime of the project. The purpose of this paper is to present the PIP-II IKC model put in place to properly integrate the IKC deliverables into the PIP-II Linac and share experience and lessons learned from its early implementation.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST020  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 21 June 2022
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MOPOST021 ReAccelerator Upgrade, Commissioning and First Experiments at the National Superconducting Cyclotron Laboratory (NSCL) / Facility for Rare Isotope Beams (FRIB) 101
 
  • A.C.C. Villari, G. Bollen, K.D. Davidson, K. Fukushima, A.I. Henriques, K. Holland, S.H. Kim, A. Lapierre, T. Maruta, D.G. Morris, S. Nashpresenter, P.N. Ostroumov, A.S. Plastun, J. Priller, B.M. Sherrill, R. Walker, T. Zhang, Q. Zhao
    FRIB, East Lansing, Michigan, USA
  • B. Arend, D.B. Crisp, D.J. Morrissey, M. Steiner
    NSCL, East Lansing, Michigan, USA
 
  Funding: Work supported by the NSF under grant PHY15-65546 and DOE-SC under award number DE-SC0000661
The reaccelerator ReA is a state-of-the-art super-conducting linac for reaccelerating rare isotope beams produced via inflight fragmentation or fission and subse-quent beam stopping. ReA was subject of an upgrade that increased its final beam energy from 3 MeV/u to 6 MeV/u for ions with charge over mass equal to 1/4. The upgrade included a new room-temperature rebuncher after the first section of acceleration, a new β = 0.085 QWR cryomodule and two new beamlines in a new ex-perimental vault. During commissioning, beams were accelerated with near 100 percent transport efficiency through the linac and delivered through beam transport lines. Measured beam characteristics match those calcu-lated. Following commissioning, stable and long living rare isotope beams from a Batch Mode Ion Source (BMIS) were accelerated and delivered to experiments. This con-tribution will briefly describe the upgrade, and results from beam commissioning and beam delivery for experi-ments.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST021  
About • Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 21 June 2022
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MOPOST022 Upgrade of the Radio Frequency Quadrupole of the ReAccelerator at NSCL/FRIB 104
 
  • A.S. Plastun, J. Brandon, A.I. Henriques, S.H. Kim, D.G. Morris, S. Nashpresenter, P.N. Ostroumov, A.C.C. Villari, Q. Zhao, S. Zhao
    FRIB, East Lansing, Michigan, USA
  • D.B. Crisp, D.P. Sanderson
    NSCL, East Lansing, Michigan, USA
 
  Funding: Work supported by the National Science Foundation under grant PHY15-65546
The ReA-RFQ is a four-rod room-temperature structure aimed to be the first step acceleration of rare isotopes as well as stable beams before injection into the ReA SRF linac. The beams of charge to mass ratios of 1/5 to 1/2 from the Electron Beam Ion Trap at 12 keV/u should be accelerated to at least 500 keV/u to be efficiently accelerated in the main SRF linac. Since the commissioning of the original ReA RFQ in 2010 the design voltage has never been reached, and CW operation was never achieved due to cooling issues. In 2016 a new design including trapezoidal modulation was proposed, which permitted achieving increased reliability, and would allow reaching the original required specifications. The proposed new rods were built and installed in 2019 and commissioned in the same year. Since then, the RFQ has been working very successfully. Recently it was opened for inspection and verification of its internal status. No damage and discoloration were observed. This contribution will describe the RFQ rebuild process, involving specific RF protections and other technical aspects related to the assembly of the structure. Results of the operation with a variety of beams will be presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST022  
About • Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 11 July 2022
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MOPOST024 A Local Modification of HL-LHC Optics for Improved Performance of the Alice Fixed-Target Layout 108
 
  • M. Patecki, D. Kikoła
    Warsaw University of Technology, Warsaw, Poland
  • A.S. Fomin, P.D. Hermespresenter, D. Mirarchi, S. Redaelli
    CERN, Meyrin, Switzerland
 
  Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme, grant agreement number 101003442 - FIXEDTARGETLAND.
The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) is the world’s largest and most powerful particle accelerator colliding beams of protons and lead ions at energies up to 7 TeV and 2.76 TeV, respectively. ALICE is one of the detector experiments optimised for heavy-ion collisions. A fixed-target experiment in ALICE is considered to collide a portion of the beam halo, split using a bent crystal, with an internal target placed a few meters upstream of the detector. Fixed-target collisions offer many physics opportunities related to hadronic matter and the quark-gluon plasma to extend the research potential of the CERN accelerator complex. Production of physics events depends on the particle flux on target. The machine layout for the fixed-target experiment is being developed to provide a flux of particles on a target high enough to exploit the full capabilities of the ALICE detector acquisition system. In this paper, we discuss a method of increasing the system’s performance by applying a local modification of optics to set the crystal at the optimal betatron phase.
marcin.patecki@pw.edu.pl
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST024  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 01 July 2022
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MOPOST025 Influences of the Transverse Motions of the Particles to the Recombination Rate of a Co-Propagating Electron-Ion System 112
 
  • G. Wang, D. Kayran, V. Litvinenko, I. Pinayev, P. Thieberger
    BNL, Upton, New York, USA
  • V. Litvinenko
    Stony Brook University, Stony Brook, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
For a system with the ion beam co-propagating with the electron beam, such as a traditional electron cooler or a Coherent electron Cooler (CeC), the recombination rate is an important observable for matching the energy of the electrons with the ions. In this work, we have developed the analytical expressions to investigate how the recombination rate depends on the energy difference of the two beams, with the influences from the transverse motions of the particles being considered. The analytical results are then used to analyze the measured recombination data collected during the CeC experiment in run 21 and run 22.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST025  
About • Received ※ 09 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 27 June 2022
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MOPOST026 Influences of the Energy Jitter to the Performance of the Coherent Electron Cooling 115
 
  • G. Wang, V. Litvinenko, J. Ma
    BNL, Upton, New York, USA
  • V. Litvinenko
    Stony Brook University, Stony Brook, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
The bandwidth of a coherent electron cooling (CeC) system is typically two to three orders of magnitude higher than the traditional RF based stochastic cooling system, which make it possible to cool the ion bunches with high energy and high intensity. However, for such broad bandwidth, jitters in the energy of the cooling electron bunches present a serious challenge to the performance of the cooling system. In this work, we present analytical as well as simulation studies about the influences of the energy jitter to a CeC system with parameters relevant to the on-going CeC experiment at RHIC.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST026  
About • Received ※ 09 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 29 June 2022
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MOPOST027 The Zgoubidoo Python Framework for Ray-Tracing Simulations with Zgoubi: Applications to Fixed-Field Accelerators 118
SUSPMF043   use link to see paper's listing under its alternate paper code  
 
  • M. Vanwelde, E. Gnacadja, C. Hernalsteens, N. Pauly, E. Ramoisiaux, R. Tesse
    ULB, Bruxelles, Belgium
  • C. Hernalsteens
    CERN, Meyrin, Switzerland
 
  The study of beam dynamics in accelerators featuring main magnets with complex geometries such as Fixed Field Accelerators (FFAs) requires simulation codes allowing step-by-step particle tracking in complex magnetic fields, such as the Zgoubi ray-tracing code. To facilitate the use of Zgoubi and to allow readily processing the resulting tracking data, we developed a modern Python 3 interface, Zgoubidoo, using Zgoubi in the backend. In this work, the key features of Zgoubidoo are illustrated by detailing the main steps to obtain a non-scaling FFA accelerator from a scaling design. The results obtained are in excellent agreement with prior results, including the tune computation and orbit shifts. These results are enhanced by Zgoubidoo beam dynamics analysis and visualization tools, including the placement of lattice elements in a global coordinate system and the computation of linear step-by-step optics. The validation of Zgoubidoo on conventional scaling and non-scaling FFA designs paves the way for future uses in innovative FFA design studies.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST027  
About • Received ※ 16 May 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022  
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MOPOST028 Tune Control in Fixed Field Accelerators 122
SUSPMF044   use link to see paper's listing under its alternate paper code  
 
  • A.F. Steinberg, R.B. Appleby
    UMAN, Manchester, United Kingdom
  • S.L. Sheehy
    The University of Melbourne, Melbourne, Victoria, Australia
 
  Fixed Field Alternating Gradient Accelerators have been proposed for a wide range of challenges, including rapid acceleration in a muon collider, and large energy acceptance beam transport for medical applications. A disadvantage of these proposals is the highly nonlinear field profile required to keep the tune energy-independent, known as the scaling condition. It has been shown computationally that approximately constant tunes can be achieved with the addition of nonlinear fields which do not follow this scaling law. However the impacts of these nonlinearities are not well understood. We present a new framework for adding nonlinearities to Fixed Field Accelerators, seeking a constant normalised focusing strength over the full energy range, and verify the results by simulation using Zgoubi. As a model use case, we investigate the degree of tune compensation that can be achieved in a Fixed Field Accelerator for ion cancer therapy.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST028  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 02 July 2022
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MOPOST029 Fast Cycling FFA Permanent Magnet Synchrotron 126
 
  • D. Trbojevic, J.S. Berg, M. Blaskiewicz, S.J. Brookspresenter
    BNL, Upton, New York, USA
 
  Funding: Work performed under the Contract Number DE-AC02-98CH10886 with the auspices of US Department of Energy
We present a novel concept of the Fixed-Field-Alternating (FFA) small racetrack proton accelerator 10x6 size, with kinetic energy range between 30-250 MeV made of permanent magnets. The horizontal and vertical tunes are fixed within the energy range, as the magnets The combined function magnets have additional sextupole and octupole multipoles the chromatic corrections, providing very fast cycling with a frequency of 1.3 KHz. The injector is 30 MeV commercially available cyclotron with RF frequency of 65 MHz. The permanent magnet synchrotron RF frequency is 390 MHz and acceleration uses the phase jump scheme.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST029  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 04 July 2022
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MOPOST030 Proton Irradiation Site for Si-Detectors at the Bonn Isochronous Cyclotron 130
 
  • D. Sauerland, R. Beck, P.D. Eversheim
    HISKP, Bonn, Germany
  • J. Dingfelder, P. Wolf
    SiLab, Bonn, Germany
 
  The Bonn Isochronous Cyclotron provides proton, deuteron, alpha particle and other light ion beams with a charge-to-mass ratio Q/A of ’ 1/2 and kinetic energies ranging from 7 to 14 MeV per nucleon. At a novel irradiation site, a 14 MeV proton beam with a diameter of a few mm is utilized to homogeneously irradiate silicon detectors, so-called devices under test (DUTs), to perform radiation hardness studies. Homogeneous irradiation is achieved by moving the DUT through the beam in a row-wise scan pattern with constant velocity and a row separation smaller than the beam diameter. During the irradiation procedure, the beam parameters are continuously measured non-destructively using a calibrated, secondary electron emission-based beam monitor, installed at the exit window of the beamline. The diagnostics and the irradiation procedure ensure a homogeneous irradiation with a proton fluence error of smaller than 2 %. In this work, an overview of the accelerator facility is given and the irradiation site with its beam diagnostics is presented in detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST030  
About • Received ※ 08 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 07 July 2022  
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MOPOST032 A New Approach to Cyclotron Design 133
 
  • O. Karamyshev
    JINR, Dubna, Moscow Region, Russia
 
  Cyclotrons are the oldest type of circular accelerators, with many applications, design of the majority of cyclotrons nowadays follow has become a standard for most of developers, and there is a clear trend for switching towards superconducting magnets to increase the magnet field level and descrease the size and weight. A new approach, described in this paper allowed the author to design a lineup of cyclotrons from 15 to 230 MeV as compact and power efficient as superconducting cyclotrons, but using copper coil.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST032  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 04 July 2022
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MOPOST033 Betatron Tune Characterization of the Rutgers 12-Inch Cyclotron for Different Magnetic Poles Configurations 136
 
  • C. Hernalsteens
    CERN, Meyrin, Switzerland
  • B.L. Beaudoin, T.W. Koeth
    UMD, College Park, Maryland, USA
  • M. Miller
    Brown University, Providence, USA
  • T.S. Ponter
    IBA, Louvain-la-Neuve, Belgium
  • K.J. Ruisard
    ORNL, Oak Ridge, Tennessee, USA
  • R. Tesse
    ULB, Bruxelles, Belgium
 
  The Rutgers cyclotron is a small 12-Inch, 1.2MeV proton cyclotron. Sets of magnet pole-tips were designed to demonstrate different cyclotron focusing options: weak focusing, radial sector focusing and spiral sector focusing. The purpose of this paper is to experimentally characterize the transverse dynamics provided by different types of focusing. Magnetic field measurements provide insight into the as-built properties of these magnetic poles configurations. First we discuss the axial betatron tune measurements as a function of the beam energy towards outer radii, which agree well with the values expected from measured magnetic data. Turn-by-turn betatron envelope oscillation measurements are also reported and compared with the tune measurements. Excellent agreement is once again found.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST033  
About • Received ※ 09 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 08 July 2022
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MOPOST035 Operational Experience and Performance of the REX/HIE-ISOLDE Linac 140
 
  • J.A. Rodriguez, N. Bidaultpresenter, E. Fadakis, P. Fernier, M.L. Lozano, S. Mataguez, E. Piselli, E. Siesling
    CERN, Meyrin, Switzerland
 
  Located at CERN, ISOLDE is one of the world’s lead-ing research facilities in the field of nuclear science. Radioactive Ion Beams (RIBs) are produced when 1.4 GeV protons transferred from the Proton Synchrotron Booster (PSB) to the facility impinge on one of the two available targets. The RIB of interest is extracted, mass-separated and transported to one of the experimental stations, either directly, or after being accelerated in the REX/HIE-ISOLDE post-accelerator. In addition to a Penning trap (REXTRAP) to accumulate and transversely cool the beam and a charge breeder (REXEBIS) to boost the charge state of the ions, the post-accelerator includes a linac with both room temperature (REX linac) and superconducting (HIE-ISOLDE linac) sections followed by three HEBT lines to deliver the beam to the different experimental stations. The latest upgrades of the facility as well as a comprehensive list of the RIBs delivered to the users of the facility and the operational experience gained during the last physics campaigns will be presented in this contribution.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST035  
About • Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 21 June 2022
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MOPOST036 Transverse Emittance Measurements of the Beams Produced by the ISOLDE Target Ion Sources 144
 
  • N. Bidault
    CERN, Meyrin, Switzerland
 
  The Isotope mass Separator On-Line DEvice (ISOLDE) is a Radioactive Ion Beam (RIB) facility based at CERN where rare isotopes are produced from 1.4 GeV-proton collisions with a target. The different types of targets and ion sources, operating conditions and ionization schemes used during the physics campaign results in extracted beams with various emittances. Characterizing the beam emittance allows deducing the transport efficiency to low-energy experimental stations (up to 60 keV) and the mass resolving power of the separators. We report on emittance measurements for different beams of stable elements extracted from surface and plasma ion sources. The dependence of the emittance on the different conditions of operation of the ion sources is investigated and the results are compared to previous measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST036  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 17 June 2022
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MOPOST037 Characterisation of Bunch-by-Bunch Tune Shift Effects in the CERN SPS 148
 
  • I. Mases Solé, H. Bartosik, V. Kainpresenter, 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) at CERN. 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. During the beam commissioning of the SPS, measurements of the bunch-by-bunch coherent tune shifts have been conducted under different beam conditions, together with appropriate corrections of the average tunes at each injection. In this paper, we describe the methodology that has been developed to acquire bunch-by-bunch position data and to perform online computations of the coherent tune spectra of each bunch using refined Fourier transform analysis. The experimental data are compared to multiparticle tracking simulations using the SPS impedance model, in view of developing an accurate model for tune correction in the SPS.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST037  
About • Received ※ 03 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022
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MOPOST038 Excitation of the σ_{l}_{l} = 90° Resonance by the Cavity RF Accelerating Fields 152
 
  • J.-M. Lagniel
    GANIL, Caen, France
 
  In RF linacs the longitudinal focusing is done by nonlinear forces and at high accelerating fields the zero-current longitudinal phase advance per longitudinal focusing period σ0ll can be high. The nonlinear components of the RF field (sextupolar, octupolar and higher order components) can then excite parametric resonances, including the 4th-order resonance (σll = 90°) when σ0ll is higher than 90°, inducing strong longitudinal emittance growths and acceptance reductions. The longitudinal beam dynamics is therefore complex, even when the nonlinear space-charge forces are ignored. The parametric resonance excitation by the RF field is analyzed before discussing the additional effect of the nonlinear space-charge forces, in particular to explain why the zero-current longitudinal phase advance per transverse focusing period σ0lt is not a relevant parameter. Examples are given in the SPIRAL2 linac case.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST038  
About • Received ※ 16 May 2022 — Accepted ※ 17 June 2022 — Issue date ※ 22 June 2022  
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MOPOST039 Algorithm to Mitigate Magnetic Hysteresis in Magnets with Unipolar Power Supplies 156
SUSPMF049   use link to see paper's listing under its alternate paper code  
 
  • J. Nasser, R.A. Baartman, O.K. Kester, S. Kiy, T. Planche, S.D. Rädel, O. Shelbaya
    TRIUMF, Vancouver, Canada
 
  Funding: National Research Council Canada
The effects of hysteresis on the fields produced by magnetic lenses are not accounted for in TRIUMF’s models of the accelerators. Under certain conditions, such as quadrupoles with unipolar power supplies operating at low currents, these effects have introduced significant field errors with consequences upon tranverse tunes. To combat these uncertainties and make the fields more reproducible and stable, a technique new to TRIUMF has been implemented. This technique ramps the current cyclically about the desired setpoint to reach a reproducible field that is independent of its history. Results of magnetic measurements at TRIUMF using this technique are presented, as well as the expected improvements to the accuracy of the beam optics model, particularly for unipolar quadrupoles.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST039  
About • Received ※ 03 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 17 June 2022
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MOPOST040 On a Framework to Analyze Single-Particle Non-Linear Beam Dynamics: Normal Form on a Critical Point 160
 
  • M. Titze
    HZB, Berlin, Germany
 
  Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association.
Normal form analysis around a stable fixed point is a well-established tool in accelerator physics and has proven to be invaluable for an understanding of non-linear beam dynamics. In this work we present progress in developing a modular Python framework to analyze some of the non-linear aspects of a storage ring, by directly operating with the given Hamiltonians. Hereby we have implemented Birkhoff’s normal form and Magnus expansion. This leads to a flexible framework to perform calculations to high order and, moreover, to relax the constraint of stability to also include certain unstable fixed points in the analysis.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST040  
About • Received ※ 31 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 25 June 2022
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MOPOST041 Dynamic Aperture Studies for the Transfer Line From FLUTE to cSTART 164
SUSPMF062   use link to see paper's listing under its alternate paper code  
 
  • J. Schäfer, B. Härer, A.-S. Müller, A.I. Papash, R. Ruprecht, M. Schuh
    KIT, Karlsruhe, Germany
 
  Funding: J. Schäfer acknowledges the support by the DFG- funded Doctoral School "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology".
The compact STorage ring for Accelerator Research and Technology cSTART project will deliver a new KIT accelerator test facility for the application of novel acceleration techniques and diagnostics. The goal is to demonstrate storing an electron beam of a Laser Plasma Accelerator (LPA) in a compact circular accelerator for the first time. Before installing an LPA, the Far-Infrared Linac and Test Experiment (FLUTE) will serve as a full energy injector for the compact storage ring, providing stable bunches with a length down to a few femtoseconds. The transport of the bunches from FLUTE to the cSTART storage ring requires a transfer line which includes horizontal, vertical and coupled deflections which leads to coupling of the dynamics in the two transverse planes. In order to realize ultra-short bunch lengths at the end of the transport line, it relies on special optics which invokes high and negative dispersion. This contribution presents dynamic aperture studies based on six-dimensional tracking through the lattice of the transfer line.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST041  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022
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MOPOST042 Using Dynamic Indicators for Probing Single-Particle Stability in Circular Accelerators 168
 
  • C.E. Montanari, A. Bazzani, G. Turchetti
    Bologna University, Bologna, Italy
  • M. Giovannozzi, C.E. Montanari
    CERN, Meyrin, Switzerland
 
  Computing the long-term behaviour of single-particle motion is a numerically intensive process, as it requires a large number of initial conditions to be tracked for a large number of turns to probe their stability. A possibility to reduce the computational resources required is to provide indicators that can efficiently detect chaotic motion, which are considered precursors to unbounded motion. These indicators could allow skilful selection of a set of initial conditions that could then be considered for long-term tracking. The chaotic nature of each orbit can be assessed by using fast-converging dynamic indicators, such as the Fast Lyapunov Indicator (FLI), the Reversibility Error Method (REM), and the Smallest and Global Alignment Index (SALI and GALI). These indicators are widely used in the field of Celestial Mechanics, but not so widespread in Accelerator Physics. They have been applied both to a modulated Hénon map, as a toy model, as well as to realistic lattices of the High-Luminosity LHC. In this paper, we discuss the results of detailed numerical studies, focusing on their performance in detecting chaotic motions.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST042  
About • Received ※ 07 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 02 July 2022  
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MOPOST043 Testing the Global Diffusive Behaviour of Beam-Halo Dynamics at the CERN LHC Using Collimator Scans 172
SUSPMF063   use link to see paper's listing under its alternate paper code  
 
  • C.E. Montanari, A. Bazzani
    Bologna University, Bologna, Italy
  • M. Giovannozzi, C.E. Montanari, S. Redaelli
    CERN, Meyrin, Switzerland
  • A.A. Gorzawski
    University of Malta, Information and Communication Technology, Msida, Malta
 
  In superconducting circular particle accelerators, controlling beam losses is of paramount importance for ensuring optimal machine performance and an efficient operation. To achieve the required level of understanding of the mechanisms underlying beam losses, models based on global diffusion processes have recently been studied and proposed to investigate the beam-halo dynamics. In these models, the building block of the analytical form of the diffusion coefficient is the stability-time estimate of the Nekhoroshev theorem. In this paper, the developed models are applied to data acquired during collimation scans at the CERN LHC. In these measurements, the collimators are moved in steps and the tail population is re-constructed from the observed losses. This allows an estimate of the diffusion coefficient. The results of the analyses performed are presented and discussed in detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST043  
About • Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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MOPOST045 A Novel Tool for Beam Dynamics Studies with Hollow Electron Lenses 176
 
  • P.D. Hermes, R. Bruce, R. De Maria, M. Giovannozzi, G. Iadarola, D. Mirarchi, S. Redaelli
    CERN, Meyrin, Switzerland
 
  Hollow Electron Lenses (HELs) are crucial components of the CERN LHC High Luminosity Upgrade (HL-LHC), serving the purpose of actively controlling the population of the transverse beam halo to reduce particle losses on the collimation system. Symplectic particle tracking simulations are required to optimize the efficiency and study potentially undesired beam dynamics effects with the HELs. With the relevant time scales in the collider in the order of several minutes, tracking simulations require considerable computing resources. A new tracking tool, Xsuite, developed at CERN since 2021, offers the possibility of performing such tracking simulations using graphics processing units (GPUs), with promising perspectives for the simulation of hadron beam dynamics with HELs. In this contribution, we present the implementation of HEL physics effects in the new tracking framework. We compare the performance with previous tools and show simulation results obtained using known and newly established simulation setups.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST045  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 08 July 2022
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MOPOST046 Enforcing the Convergence of Longitudinal Bunch Density Calculation in the Presence of a Harmonic Cavity Through Anderson Acceleration Method 180
 
  • I. Carvalho de Almeida
    CNPEM, Campinas, SP, Brazil
  • M. Hoffmann Wallnerpresenter, A.P.B. Lima
    LNLS, Campinas, Brazil
 
  Sirius is a 4th generation synchrotron light source at the Brazilian Center for Research in Energy and Materials in Campinas, Brazil. A passive superconducting third harmonic cavity is planned to be installed in the storage ring in order to lengthen the bunches and increase beam lifetime by reducing Touschek scattering while keeping its high brightness. This paper presents the results obtained in applying Anderson acceleration method to enforce the convergence of the self-consistent algorithm used for calculation of the equilibrium longitudinal bunch density in the presence of a harmonic cavity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST046  
About • Received ※ 08 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 18 June 2022  
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MOPOST047 Determination of the Phase-Space Stability Border with Machine Learning Techniques 183
 
  • F.F. Van der Veken, R. Akbari, M.P. Bogaert, E. Fol, M. Giovannozzi, A.L. Lowyck, C.E. Montanari, W. Van Goethem
    CERN, Meyrin, Switzerland
 
  The dynamic aperture (DA) of a hadron accelerator is represented by the volume in phase space that exhibits bounded motion, where we disregard any disconnected parts that could be due to stable islands. To estimate DA in numerical simulations, it is customary to sample a set of initial conditions using a polar grid in the transverse planes, featuring a limited number of angles and using evenly distributed radial amplitudes. This method becomes very CPU intensive when detailed scans in 4D, and even more in higher dimensions, are used to compute the dynamic aperture. In this paper, a new method is presented, in which the border of the phase-space stable region is identified using a machine learning (ML) model. This allows one to optimise the computational time by taking the complex geometry of the phase space into account, using adaptive sampling to increase the density of initial conditions along the border of stability.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST047  
About • Received ※ 06 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 20 June 2022  
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MOPOST048 Efficient Representation of Realistic 3D Static Magnetic Fields for Symplectic Tracking and First Applications for Frequency Analysis and Dynamic Aperture Studies in ELENA 187
 
  • L. Bojtár
    CERN, Meyrin, Switzerland
 
  The algorithm called SIMPA has a new and unique approach to long-term 4D tracking of charged particles in arbitrary static electromagnetic fields. Field values given on the boundary of the region of interest are reproduced by an arrangement of hypothetical magnetic or electric point sources surrounding the boundary surface. The vector and scalar potentials are obtained by summing the contributions of each source. The second step of the method improves the evaluation speed of the potentials and their derivatives by orders of magnitude. This comprises covering the region of interest by overlapping spheres, then calculating the spherical harmonic expansion of the potentials on each sphere. During tracking, field values are evaluated by calculating the solid harmonics and their derivatives inside a sphere containing the particle. Frequency analysis and dynamic aperture studies in ELENA is presented. The effect of the end fields and the perturbation introduced by the magnetic system of the electron cooler on dynamic aperture is shown. The dynamic aperture calculated is the direct consequence of the geometry of the magnetic elements, no multipole errors have been added to the model.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST048  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 01 July 2022
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MOPOST049 Electron Cloud Build-Up for the Arc Sextupole Sections of the FCC-ee 191
 
  • J.E. Rocha Muñoz, G.H.I. Maury Cuna
    Universidad de Guanajuato, División de Ciencias e Ingenierías, León, Mexico
  • K.B. Cantún-Ávila
    UADY, Mérida, Yucatán, Mexico
  • F. Zimmermannpresenter
    CERN, Meyrin, Switzerland
 
  Funding: Consejo Nacional de Ciencia y Tecnología (CONACyT) - México
In particle accelerators that operate with positrons, an electron cloud may occur due to several mechanisms. This work reports preliminary studies on electron cloud build-up for the arc sextupole sections of the positron ring of the FCCe+e using the code PyECLOUD. We compute the electron cloud evolution while varying strategic parameters and consider three simulation scenarios. We report the values of the central density just before the bunch passage, which is related to the single-bunch instability threshold and the electron density threshold for the three scenarios. In addition, we compare the simulated electron distribution across the central circular cross-section for a chamber with and without winglets.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST049  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 25 June 2022
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MOPOST050 Third-Order Resonance Compensation at the FNAL Recycler Ring 195
SUSPMF064   use link to see paper's listing under its alternate paper code  
 
  • C.E. Gonzalez-Ortiz
    MSU, East Lansing, Michigan, USA
  • R. Ainsworth
    Fermilab, Batavia, Illinois, USA
  • P.N. Ostroumov
    FRIB, East Lansing, Michigan, USA
 
  The Recycler Ring (RR) at the Fermilab Accelerator Complex performs slip-stacking on 8 GeV protons, doubling the beam intensity delivered to the Main Injector (MI). At MI, the beam is accelerated to 120 GeV and delivered to the high energy neutrino experiments. Femilab’s Proton Improvement Plan II (PIP-II) will require the Recycler to store 50% more beam. Simulations have shown that the space charge tune shift at this new intensity will lead to the excitation of multiple resonance lines. Specifically, this study looks at normal sextupole lines 3 Qx=76 and Qx+2Qy=74, plus skew sextupole lines 3 Qy=73 and 2 Qx+Qy=75. Dedicated normal and skew sextupoles have been installed in order to compensate for these resonance lines. By measuring and calculating the Resonance Driving Terms (RDT), this study shows how each of the resonance lines can be compensated independently. Furthermore, this study shows and discusses initial investigations into compensating multiple lines simultaneously.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST050  
About • Received ※ 09 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 21 June 2022  
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MOPOST051 Study of Transverse Resonance Island Buckets at CESR 199
 
  • S. Wang, V. Khachatryan
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: Work supported by NSF PHYS-1416318 and DMR-1829070.
A 6-GeV lattice with the horizontal tune near a 3rd-order resonance line at 3νx=2 is designed for studying the transverse resonance island buckets (TRIBs) at the Cornell Electron Storage Ring (CESR). The distribution of 76 sextupoles powered individually is optimized to maximize the dynamic aperture and achieve the desired amplitude-dependent tune shift αxx and the resonant driving term h30000, which are necessary conditions to form stable island buckets. The particle tracking simulations are developed to check and confirm the formation of TRIBs at different tunes with clearing kicks in this TRIBs lattice. Finally, the lattice is loaded in CESR and the TRIBs are successfully observed when the horizontal fractional tune is adjusted to 0.665, close to the 3rd-order resonance line. Bunch-by-bunch feedback is also explored to clear the particles in the main bucket and the island buckets, respectively.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST051  
About • Received ※ 20 May 2022 — Revised ※ 09 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 25 June 2022
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MOPOST053 Transverse Resonance Islands Buckets at SPEAR3 203
 
  • J. Kim, J.A. Safranek, K. Tian
    SLAC, Menlo Park, California, USA
 
  We present populating bunches into the transverse resonance islands buckets (TRIBs) on SPEAR3. As one of operation modes for the timing-mode or providing separated bunches in transverse direction, we are exploring TRIBs on SPEAR3. Experience and analysis on applying kicks multiple times using the bunch-by-bunch feedback kicker to move bunches into the TRIBs is described.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST053  
About • Received ※ 06 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022
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MOPOST054 A Hybrid Multi-Bend Achromat Lattice Design for SSRL-X 207
 
  • J. Kim, X. Huang, P. Raimondi, J.A. Safranek, M. Song, K. Tian
    SLAC, Menlo Park, California, USA
 
  We present a lattice design for SSRL-X which is a green-field low-emittance storage ring proposal. The lattice is based on the hybrid multi-bend achromat and has natural emittance of 63 pm with 24-cells periodicity and ~570 m circumference under 3.5 GeV energy. Modification on dedicated cells which lengthens straight sections but keeps the phase advance is explored to further reduce the natural emittance by inserting damping wigglers.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST054  
About • Received ※ 06 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 09 July 2022
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MOPOST055 The EIC Rapid Cycling Synchrotron Dynamic Aperture Optimization 210
 
  • H. Lovelace III, C. Montagpresenter, V.H. Ranjbar
    BNL, Upton, New York, USA
  • F. Lin
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  With the design of the Electron-Ion Collider (EIC), a new Rapid Cycling Synchrotron (RCS) must be designed to accelerate the electron bunches from 400 MeV up to 18 GeV. An optimized dynamic aperture with preservation of polarization through the energy ramp was found. The codes DEPOL, MAD-X, and BMAD are used in modeling the dynamics and spin preservation. The results will be discussed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST055  
About • Received ※ 27 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 08 July 2022
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MOPOST056 Interplay between Space Charge and Intra-beam Scattering for the CERN Ion Injectors 214
SUSPMF073   use link to see paper's listing under its alternate paper code  
 
  • M. Zampetakis, F. Antoniou, F. Asvesta, H. Bartosik, Y. Papaphilippou
    CERN, Meyrin, Switzerland
 
  The CERN ion injectors, SPS and LEIR, operate in a strong space charge and intra-beam scattering regime, which can lead to degradation of their beam performance. To optimize machine performance requires thus to study the interplay of these two effects in combined space charge and intrabeam scattering tracking simulations. In this respect, the kinetic theory approach of intra-beam scattering has been implemented in pyORBIT and benchmarked against analytical models. First results of combined space charge and intra-beam scattering simulations for SPS and LEIR are presented in this contribution. The simulation results are compared with observations from beam measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST056  
About • Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 07 July 2022
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MOPOST057 Characterization of the Vertical Beam Tails in the CERN PS Booster 218
 
  • T. Prebibaj, F. Antoniou, F. Asvesta, H. Bartosik, C. Bracco, G.P. Di Giovanni, E. Renner
    CERN, Meyrin, Switzerland
 
  The CERN Proton Synchrotron Booster (PSB) went through major upgrades in the framework of the LHC Injectors Upgrade Project (LIU) aiming to double the brightness of the LHC beams. Operation restarted in early 2021, demonstrating the expected performance improvement. The high-brightness beams, nevertheless, appear to have overpopulated tails in the vertical beam profiles, both at injection and at extraction energies. In an attempt to understand the origin and evolution of the observed tails, systematic profile measurements were performed for different machine and beam configurations using Wire Scanners (WS). The results are presented in this report and compared to simulations. The effect of the Coulomb scattering of the wire to the beam distribution is also addressed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST057  
About • Received ※ 03 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022
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MOPOST058 Studies on the Vertical Half-Integer Resonance in the CERN PS Booster 222
SUSPMF074   use link to see paper's listing under its alternate paper code  
 
  • T. Prebibaj, F. Antoniou, F. Asvesta, H. Bartosik
    CERN, Meyrin, Switzerland
  • G. Franchetti
    GSI, Darmstadt, Germany
 
  Following the upgrades of the LHC Injectors Upgrade Project (LIU), the Proton Synchrotron Booster (PSB) at CERN successfully delivers beams with double brightness. An important contributing factor for this was the dynamic correction of the beta-beating induced by the injection chicane, which allowed stable operation closer to the half-integer resonance. Ideally, injection above the half-integer resonance could further improve the beam brightness. In this context, a series of studies were initiated in order to characterize the effects of space charge when crossing the half-integer resonance. In this contribution, the first results of these investigations are reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST058  
About • Received ※ 03 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 24 June 2022
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