MC4: Hadron Accelerators
A04 Circular Accelerators
Paper Title Page
MOPGW069 Recent Beam Performance Achievements with the Pb-Ion Beam in the SPS for LHC Physics Runs 250
 
  • H. Bartosik, R. Alemany-Fernández, T. Argyropoulos, T. Bohl, H. Damerau, V. Kain, G. Papotti, G. Rumolo, Á. Saá Hernández, E.N. Shaposhnikova
    CERN, Meyrin, Switzerland
 
  In the SPS, which is the last accelerator in the LHC ion injector chain, multiple injections of the Pb-ion beam have to be accumulated. On this injection plateau the beam suffers from considerable degradation such as emittance growth and losses. This paper summarises the achievements on improving the beam parameters and maximising the performance of the Pb-ion beam for the LHC physics run in 2018. The results are discussed in view of the target beam parameters of the LHC injectors upgrade project, which is being deployed during the presently ongoing long shutdown.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW069  
About • paper received ※ 12 May 2019       paper accepted ※ 17 May 2019       issue date ※ 21 June 2019  
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MOPMP013 New Nuclotron Beam Lines and Stations for Applied Researches 449
 
  • E. Syresin, A.A. Baldin, A.V. Butenko, G.A. Filatov, A.A. Slivin, G.N. Timoshenko, G.V. Trubnikov, A. Tuzikov
    JINR, Dubna, Moscow Region, Russia
  • D.V. Bobrovskiy, A.I. Chumakov
    MEPhI, Moscow, Russia
  • M.M. Kats, T. Kulevoy, D.A. Liakin, Y.E. Titarenko
    ITEP, Moscow, Russia
 
  New beamlines for applied researches on the Nuclotron are under development within the framework of implementation of the NICA accelerator facility. Ion beams with energies of 150-800 MeV/n extracted from the Nuclotron will be used for radiobiological researches and modeling of cosmic rays interactions with microchips. Equipment of two experimental stations is under development by the JINR-ITEP-MEPhi collaboration for these applied researches. Ion beams with the energy of 3.2 MeV/n extracted from the heavy ion linac HILAc will also be used for irradiation and testing of microchips. The specialized channel will be reconstructed for investigations in the field of relativistic nuclear power at light ion energies of 0.3-4.5 GeV/n. Three new experimental areas are organized for applied physics researches within the framework of implementation of the NICA accelerator facility.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP013  
About • paper received ※ 29 April 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS010 Simulation of the Guide Field Flipping Procedure for the Frequency Domain Method 858
 
  • A.E. Aksentyev
    FZJ, Jülich, Germany
  • A.E. Aksentyev
    MEPhI, Moscow, Russia
  • A.E. Aksentyev, V. Senichev
    RAS/INR, Moscow, Russia
 
  The spin vector of a particle injected into a perfectly aligned storage ring precesses about the vertically-orientated guide field. In the presence of an Electric Dipole Moment (EDM), the spin precession axis acquires a proportional radial component. However, in an imperfect ring, rotational magnet misalignments induce a radial component to the spin precession axis, related to the Magnetic Dipole Moment (MDM). In the Frequency Domain Method, [*] this additional precession is dealt with by consecutively injecting the beam in opposite directions, and constructing the EDM estimator as the sum of the clockwise and counter-clockwise vertical plane precession frequencies. Since the radial MDM component changes sign when the magnetic field direction is reversed, it cancels in the sum, leaving only the EDM effect. In order to reproduce the guide field magnitude with precision sufficient for the cancellation of the MDM effect, we propose to calibrate the guide field via the horizontal plane precession frequency. In the present work we describe the algorithm of the field flipping procedure, and do a numerical simulation.
[*] Senichev Y, Aksentev A, Ivanov A, Valetov E. Frequency domain method of the search for the deuteron electric dipole moment in a storage ring with imperfections. arXiv:171106512. 2017 Nov 17.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS010  
About • paper received ※ 08 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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MOPTS011 Spin Motion Perturbation Effect on the EDM Statistic in the Frequency Domain Method 861
 
  • A.E. Aksentyev
    FZJ, Jülich, Germany
  • A.E. Aksentyev
    MEPhI, Moscow, Russia
  • A.E. Aksentyev, V. Senichev
    RAS/INR, Moscow, Russia
 
  The spin precession axis of a particle involved in betatron motion precesses about the invariant spin axis defined on the closed orbit (CO). This precession can be observed in polarization data as a rapid, small-amplitude oscillation on top of the major effect oscillation caused by the precession of spin about the CO axis. The frequency of this latter oscillation is used in the Frequency Domain (FD) methodology as the EDM observable. [*] It is estimated by fitting polarimetry data by a sine function; the rapid oscillations, therefore, constitute a model specification error. This model error might introduce a bias into the frequency estimate. In the present work we investigate the effect of the spin precession axis motion on measurement data and fit quality, and conclude that it is not only insignificant (with regard to data perturbation) compared to spin tune variation, but is also controllable via the application of a Spin Wheel.
[*] Senichev Y, Aksentev A, Ivanov A, Valetov E. Frequency domain method of the search for the deuteron electric dipole moment in a storage ring with imperfections. arXiv:171106512. 2017 Nov 17
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS011  
About • paper received ※ 08 April 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS012 Spin Decoherence in the Frozen Spin Storage Ring Method of Search for a Particle EDM 864
SUSPFO011   use link to see paper's listing under its alternate paper code  
 
  • A.E. Aksentyev
    FZJ, Jülich, Germany
  • A.E. Aksentyev
    MEPhI, Moscow, Russia
  • A.E. Aksentyev, V. Senichev
    RAS/INR, Moscow, Russia
 
  Spin coherence refers to a measure of preservation of polarization in an initially polarized beam. The spin vector of a particle injected into a storage ring starts to precess about the vertical magnetic field vector in accordance with the Thomas-BMT equation. The precession frequency is dependent on the equilibrium-level energy, which differs across the beam particles. This does not pose a problem when the initial polarization is vertical; however, the Frozen Spin Storage Ring EDM search method [*] requires beam polarization along the momentum vector, i.e., in the horizontal plane. In the present work we analyze the source of decoherence, and investigate the way it can be suppressed in the horizontal plane in a perfectly aligned ring by means of sextupole fields. We also consider the case of an imperfect ring: transference of decoherence into the vertical plane induced by vertical plane spin precession, and the effect of sextupole fields.
* D. Anastassopoulos et al. AGS Proposal: Search for a permanent electric dipole moment of the deuteron nucleus at the 10 −29 e · cm level. BNL report, 2008.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS012  
About • paper received ※ 08 April 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS028 Search for Electric Dipole Moments at Cosy in Jülich - Spin-Tracking Simulations Using Bmad 914
SUSPFO023   use link to see paper's listing under its alternate paper code  
 
  • V. Poncza, A. Lehrach
    FZJ, Jülich, Germany
  • A. Lehrach, V. Poncza
    RWTH, Aachen, Germany
 
  The observed matter-antimatter asymmetry in the universe cannot be explained by the Standard Model (SM) of particle physics. In order to resolve the matter dominance an additional CP violating phenomenon is needed. A candidate for physics beyond the SM is a non-vanishing Electric Dipole Moment (EDM) of subatomic particles. Since permanent EDMs violate parity and time reversal symmetries, they are also CP violating if the CPT -theorem is assumed. The JEDI (Jülich Electric Dipole moment Investigations) collaboration in Jülich is preparing a direct EDM measurement of protons and deuterons first at the storage ring COSY (COoler SYnchrotron) and later at a dedicated storage ring. In order to analyse the data and to disentangle the EDM signal from systematic effects spin tracking simulations are needed. Therefore a model of COSY was implemented using the software library Bmad. It includes the measured magnet misalignments of the latest survey and a simplified description of the RF-Wien Filter device that is used for the EDM measurement. The model was successfully benchmarked using analytical predictions of the spin behavior. A crucial point regarding the data analysis is the knowledge of the orientation of the invariant spin axis with vanishing EDM at the position of the RF-Wien Filter. Especially its radial component is unknown and spin tracking simulations can be used to determine this missing number. Tracking results as well as the algorithm to find the invariant spin axis will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS028  
About • paper received ※ 25 April 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS035 Recommissioning of SIS18 After FAIR Upgrades 932
 
  • D. Ondreka, C. Dimopoulou, H.C. Hüther, H. Liebermann, J. Stadlmann, R.J. Steinhagen
    GSI, Darmstadt, Germany
 
  The synchrotron SIS18 of the GSI facility has recently resumed beam operation after a long shutdown, during which major upgrades for the operation of SIS18 in the FAIR facility were realized. This signifies a major milestone for the mission of GSI and FAIR. On one hand, the scientific program of GSI depends strongly on beam from SIS18, including the very important developments of detectors for FAIR experiments. On the other hand, large parts of the existing GSI accelerator facility, including SIS18, are now operated with the FAIR control system, demonstrating its suitability for control of a large scale accelerator facility. Commissioning of the new control system started during the shutdown with a series of dry runs, which proved very useful to establish the basic functionalities. Recommissioning of SIS18 was further facilitated by the fact that the machine model of SIS18, implemented in the modeling framework LSA, had already been tested with beam several years before the shutdown. Thus, all operation modes of SIS18, including multi-turn injection, electron cooling, as well as fast and slow extraction could be successfully commissioned during the first weeks of operation. Other commissioning activities concerned the operation of new devices installed during the shutdown. These devices, mostly installed to prepare SIS18 for the operation with FAIR design parameters, open new possibilities in the standard operation of SIS18. A challenge for the operation of SIS18 is posed by ground motion due to ground water lowering for the nearby FAIR construction site. Surveys revealed that SIS18 subsided by several centimeters during one year. Even though the machine was realigned prior to recommissioning, the dynamics of the ground motion will continue to affect operation of SIS18.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS035  
About • paper received ※ 15 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS045 The Betatron Equation with the Synchro-Betatron Coupling Term and Suppression of the Coupled Bunch Mode 957
 
  • K. Jimbo
    Kyoto University, Kyoto, Japan
 
  The synchrotron oscillation, which is both longitudinal and horizontal oscillations, occurs under a constant longitudinal velocity of revolving particle. The synchrotron and betatron equations for revolving particles are derived from the improved Hamiltonian. The betatron equation accompanys the shinchro-betatron resonant coupling term. The coherent synchrotron oscillation frequency of the bunch is defined from the integrated phase. Taking advantage of the resonant coupling term, an experiment to suppress magnetically the destabilized coupled-bunch mode of the synchrotron oscillation is proposed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS045  
About • paper received ※ 17 April 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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MOPTS060 SESRI 300 MeV Proton and Heavy Ion Accelerator 998
 
  • H. P. Jiang, Q.M. Chen, W. Chen, Z.N. Han, H.F. Hao, J. Liu, J. Zhang, T. Zhang
    Harbin Institute of Technology(HIT), Harbin, People’s Republic of China
 
  The SESRI (Space Environment Simulation and Research Infrastructure) is the new national research infrastructure under construction at Harbin Institute of Technology (HIT) in China. This infrastructure is specifically built to simulate the space environment on the ground. The SESRI has kinds of accelerators, and the 300MeV proton and heavy ion accelerator is a major radiation source, which will supply 100-300MeV protons and 7-85MeV/u heavy ions for studying the interaction of high energy space particle radiation with material, device, module and life. To meet above requirements, the facility adopts the combination of room temperature ECR (Electron Cyclotron Resonance) ion source, linac injector and synchrotron. The ion source is required to provide all stable nuclide beams from H2+ to Bi. The linac injector supplies 1MeV/u heavy ion beams and 5MeV proton beam by using RFQ (Radio Frequency Quadrupole) and IH-DTL (Interdigital H-mode type Drift Tube Linac) linac structures. The synchrotron accelerates heavy ions up to 85MeV/u and proton beam 300MeV. And the 3rd integer resonance and RF-KO (RF-Knock-Out) method are adopted for slow extraction. The status of 300MeV proton and heavy ion accelerator design and construction works are briefly described below.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS060  
About • paper received ※ 22 April 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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MOPTS068 Beam Commissioning Experience of CSNS/RCS 1012
 
  • S.Y. Xu
    DNSC, Dongguan, People’s Republic of China
 
  The China Spallation Neutron Source (CSNS) is an accelerator-based science facility. CSNS is designed to accelerate proton beam pulses to 1.6 GeV kinetic energy, striking a solid metal target to produce spallation neutrons. CSNS has two major accelerator systems, a linear accelerator (80 MeV Linac) and a 1.6 GeV rapid cycling synchrotron (RCS). The Beam commissioning of CSNS/RCS has been commissioned recently. Beam had been accelerated to 1.6 GeV at CSNS/RCS on January 18, 2018 with the injection energy of 80 MeV. The machine parameters are measured and optimized. The beam power is increased step by step. The beam power achieved 50kW in January, 2019. In this paper, the commissioning experiences are introduced.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS068  
About • paper received ※ 15 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS086 Identification and Compensation of Betatronic Resonances in the Proton Synchrotron Booster at 160 Mev 1054
 
  • A. Santamaría García, S.C.P. Albright, F. Antoniou, F. Asvesta, H. Bartosik, G.P. Di Giovanni, B. Mikulec
    CERN, Geneva, Switzerland
  • F. Asvesta
    NTUA, Athens, Greece
  • H. Rafique
    University of Manchester, Manchester, United Kingdom
 
  The Proton Synchrotron Booster (PSB) is the first circular accelerator in the injector chain to the Large Hadron Collider (LHC) and accelerates protons from 50 MeV to 1.4 GeV. The PSB will need to deliver two times the current brightness after the LHC Injectors Upgrade (LIU) in order to meet the High Luminosity LHC (HL-LHC) beam requirements. At the current injection energy a large incoherent space charge tune spread limits the brightness of the beams, which is one of the main motivations to increase the injection energy to 160 MeV with the injection provided by Linac4, a new H linear accelerator. The higher injection energy will allow doubling the beam intensity while maintaining a space charge tune spread similar to current values. The degradation of the beam brightness due to the tune spread can be minimized with a proper choice of working point and an efficient compensation of resonances. In this paper, we present the measurement of the betatronic resonances in the four rings of the PSB at 160 MeV before the Long Shutdown 2, as well as the results of a proposed compensation scheme.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS086  
About • paper received ※ 13 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS087 Transverse Emittance Studies at Extraction of the CERN PS Booster 1058
 
  • F. Antoniou, S.C.P. Albright, F. Asvesta, H. Bartosik, G.P. Di Giovanni, V. Forte, M.A. Fraser, A. Garcia-Tabares, A. Huschauer, B. Mikulec, T. Prebibaj, A. Santamaría García, P.K. Skowroński
    CERN, Meyrin, Switzerland
  • F. Asvesta
    NTUA, Athens, Greece
  • T. Prebibaj
    National Technical University of Athens, Zografou, Greece
 
  Transverse emittance discrepancy in the beam transfer between the Proton Synchrotron Booster (PSB) and the Proton Synchrotron (PS) is observed in operational conditions for the LHC beams at CERN. The ongoing LHC Injectors Upgrade (LIU) project requires a tight budget for beam degradation along the injector chain and therefore the reason for this emittance discrepancy needs to be understood. Systematic measurements have been performed for various beam characteristics (beam intensity, transverse and longitudinal emittance). In this paper, a comparison between the emittance measurements using all available beam instrumentation with different emittance computation algorithms is presented. The results are compared to measurements at PS injection. Furthermore, the impact on the LIU project requirements for the emittance preservation along the LHC Injectors Complex is discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS087  
About • paper received ※ 14 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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MOPTS089 Transverse Beam Dynamics Studies With High Intensity LHC Beams in the SPS 1062
 
  • M. Carlà, H. Bartosik, M.S. Beck, L.R. Carver, V. Kain, G. Kotzian, K.S.B. Li, G. Rumolo, C. Zannini
    CERN, Geneva, Switzerland
 
  In order to reach the target beam parameters of the LHC injectors upgrade (LIU), about twice the presently operational intensity of LHC type beams has to be achieved. Although the planned upgrade of the main RF system will occur during the long shutdown, a series of measurements have been performed to assess the beam dynamics challenges with these very high intensity beams on the long SPS injection plateau. Bunch-by-bunch transverse emittance blow-up measurements suggested the presence of electron-cloud. After a period of running with the high intensity beam for a couple of days, a clear improvement of beam quality was observed which is attributed to scrubbing. In addition, a horizontal headtail instability is encountered for the usual operational settings of chromaticity and transverse damper. The stability limit as a function of chromaticity and Landau octupole settings has been explored and will be discussed, together with possible sources of the instability and mitigation strategies.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS089  
About • paper received ※ 06 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019  
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MOPTS090 Beam-Based Measurement of the Skew-Sextupolar Component of the Radio Frequency Field of a HL-LHC-Type Crab-Cavity 1066
 
  • M. Carlà, A. Alekou, H. Bartosik, L.R. Carver
    CERN, Geneva, Switzerland
 
  Two High Luminosity Large Hadron Collider (LHC) type crab-cavities have been installed in the CERN SPS for testing purposes. An attempt to characterize the skew-sextupolar component of the radio frequency field of the crab-cavity (a3) has been carried out by means of beam-based techniques using turn-by-turn monitoring of the betatron motion. The skew nature of a3 couples the horizontal and vertical betatron motions through a non-linear term. Therefore by exciting the horizontal betatron motion it was possible to observe a spectral line in the vertical beam motion driven by the non-linear coupling at the characteristic frequency 2Qx. A measurement of the magnitude of a3 was thus obtained by characterizing amplitude and phase of such line. The results of the measurements are discussed here.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS090  
About • paper received ※ 06 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019  
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MOPTS091 Mechanical Robustness of HL-LHC Collimator Designs 1070
 
  • F. Carra, A. Bertarelli, G. Gobbi, J. Guardia, M. Guinchard, F.J. Harden, M. Pasquali, S. Redaelli, E. Skordis
    CERN, Meyrin, Switzerland
 
  Funding: This work has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No. 730871. Research supported by the HL-LHC project.
Two new absorbing materials were developed as collimator inserts to fulfil the requirements of HL-LHC higher brightness beams: molybdenum-carbide graphite (MoGr) and copper-diamond (CuCD). These materials were tested under intense beam impacts at CERN HiRadMat facility in 2015, when full jaw prototypes were irradiated. Additional tests in HiRadMat were performed in 2017 on another series of material samples, including also improved grades of MoGr and CuCD, and different coating solutions. This paper summarizes the main results of the two experiments, with a main focus on the behaviour of the novel composite blocks, the metallic housing, as well as the cooling circuit. The experimental campaign confirmed the final choice for the materials and the design solutions for HL-LHC collimators, and constituted a unique chance of benchmarking numerical models. In particular, the tests validated the selection of MoGr for primary and secondary collimators, and CuCD as a valid solution for robust tertiary collimators.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS091  
About • paper received ※ 12 April 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS092 Numerical and Experimental Evaluation of the DQW Crab Cavity Cryomodule Thermal Budget 1074
 
  • F. Carra, K. Brodzinski, E. Cano-Pleite, O. Capatina
    CERN, Meyrin, Switzerland
 
  Funding: Research supported by the HL-LHC project
One of the key devices of the HL-LHC project are SRF Crab Cavities. A cryomodule with two Double Quarter Wave (DQW) crab cavities has been fabricated at CERN in 2017 and successfully tested with beam in the Super Proton Synchrotron (SPS) in 2018. The aim of the present study is to present and compare the estimation of the thermal budget for the different components of the cryomodule, performed with numerical and semi-analytical methods, with the experimental measurements carried out on the cryomodule after installation in the SPS.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS092  
About • paper received ※ 12 April 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS093 Ultra-High Vacuum Characterization of Molybdenum-Carbide Graphite for HL-LHC Collimators 1078
 
  • F. Carra, C. Accettura, A. Bertarelli, G. Bregliozzi, G. Cattenoz, S. Redaelli, M. Taborelli
    CERN, Meyrin, Switzerland
  • M. Beghi
    POLIMI, Milano, Italy
  • J. Guardia Valenzuela
    Universidad de Zaragoza, Zaragoza, Spain
 
  Funding: This work has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No. 730871. Research supported by the HL-LHC project
In view of the High-Luminosity upgrade of the Large Hadron Collider (LHC) collimation system, a family of novel molybdenum-carbide graphite (MoGr) composites was developed to meet the challenging requirements of HL-LHC beam-halo collimation, in particular the electrical conductivity and thermo-mechanical performances. The Ultra-High Vacuum (UHV) behaviour of this material was extensively characterized to assess its compatibility with the accelerator’s specifications. The results presented in this paper correlate the outgassing behaviour with the microscopic features of MoGr compared to other graphite-based materials. Residual gas analysis (RGA) was exploited to optimize post-production treatments.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS093  
About • paper received ※ 12 April 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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MOPTS094 Dust Analysis from LHC Vacuum System to Identify the Source of Macro-Particle-Beam-Interactions 1082
SUSPFO100   use link to see paper's listing under its alternate paper code  
 
  • L. K. Grob, A. Apollonio, C. Charvet, E. Garcia-Tabares Valdivieso, H. Kos, R. Schmidt
    CERN, Geneva, Switzerland
  • C. Neves
    Hochschule Furtwangen, Furtwangen, Germany
 
  Since in 2010 the first sub-millisecond beam losses were observed at varying locations all along the LHC, it is well known that dust can interact with high-intensity proton beams and cause significant beam losses. Initially the sudden localized losses were enigmatic and coined the phrase ’unidentified falling objects’ (UFOs), which is still widely used. These very fast beam losses have resulted in hundreds of premature beam dumps and even magnet quenches since the start of LHC. So far, the only mitigation strategy involved an optimization of dump thresholds and the beneficial conditioning effect which leads to a reduction of the UFO rate over time. To understand the physics involved in these events and to allow an active diminution, it is essential to know the chemical composition and the size of the dust particulates interacting with the protons. The exchange of a dipole magnet offered the unique opportunity to collect dust samples from inside the LHC vacuum system. They were extracted from the various components and analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy to reveal size distribution and abundant elements. The results of this investigation will optimize the existing UFO models and the improved understanding of the phenomenon may help to prevent future performance limitations. This is also of relevance for future projects, in particular for the Future Circular Collider (FCC) under study.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS094  
About • paper received ※ 15 May 2019       paper accepted ※ 24 May 2019       issue date ※ 21 June 2019  
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MOPTS099 The Development Programme of Cathodes and Electron Guns for the Hollow Electron Lenses of the High Luminosity LHC Project 1102
 
  • D. Perini, G. Gobbi
    CERN, Geneva, Switzerland
  • D.J. Crawford, J. Ruan, G. Stancari, L.R. Valerio
    Fermilab, Batavia, Illinois, USA
  • J. Feng, Z. Li, W. Shao, K. Zhang
    BVERI, Beijing, People’s Republic of China
  • W. Liu, J. Wang, Y. Wang, Y. Yang
    Beijing University of Technology, Beijing, People’s Republic of China
 
  Funding: Research supported by the HL-LHC project
The High Luminosity LHC project (HL-LHC) foresees the construction and installation of important new equipment to increase the performance of the LHC machine. The Hollow Electron Lens (HEL) is a promising system to control the beam halo. It improves the beam collimation system of the HL-LHC and mitigates possible equipment damage in case of failure scenarios from halo losses. The halo can store up to 30 MJ energy. The specifications for this new device are quite demanding. The source, an electron gun with an annular shaped cathode, has to deliver a current up to 5 A. This is five times higher than the current in the existing electron lenses in Fermi and Brookhaven national laboratories. This note describes the programme carried out to design and test high-perveance guns equipped with two types of high-performance scandate cathodes. The size of the final gun is now considerably smaller than the one of the first prototype, allowing a reduction of diameter and cost of the superconducting magnet system used to steer the electron beam. The tests carried out at FNAL, BVERI and BJUT demonstrated that the developed cathodes fulfil the specifications and can supply a 5 A fully Space Charge Limited (SCL) current.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS099  
About • paper received ※ 17 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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MOPTS100 Transverse Emittance Measurement in the CERN Proton Synchrotron in View of Beam Production for the High-Luminosity LHC 1106
SUSPFO107   use link to see paper's listing under its alternate paper code  
 
  • E. Senes, J. Emery, V. Forte, M.A. Fraser, A. Guerrero, A. Huschauer, F. Roncarolo, J.L. Sirvent, P.K. Skowroński, F. Tecker
    CERN, Geneva, Switzerland
 
  In the framework of the LHC Injectors Upgrade project the improvements required to achieve the parameters of the future beams for the High-Luminosity LHC are being studied and implemented. In order to deliver high brightness beams, control over the beam intensity and emittance is fundamental. Therefore, a highly accurate and reliable transverse emittance measurement is essential. Presently at the CERN Proton Synchrotron, the only operationally available emittance monitors not impacting the facility beam production are the flying wire scanners used to measure the circulating beam profile. The wire scanners will be replaced with a new generation in the next two years and a prototype is already installed. The prototype has been commissioned with beams featuring a wide range of intensities and emittances. This paper evaluates the performance of the prototype with respect to the present system via beam-based measurements. The transverse emittance measurement is discussed, considering the different potential error contributions to the measurement, such as knowledge of the machine optics and the dispersive contribution to the beam size.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS100  
About • paper received ※ 02 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS101 Study of the Transverse Emittance Blow-Up Along the Proton Synchrotron Booster Cycle During Wire Scanner Operation 1110
 
  • A. Santamaría García, F. Antoniou, H. Bartosik, J.A. Briz Monago, G.P. Di Giovanni, A. Guerrero, J.R. Hunt, B. Mikulec, F. Roncarolo, E. Senes, V. Vlachoudis
    CERN, Geneva, Switzerland
  • E. Senes
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
 
  Transverse emittance measurements with wire scanners have been extensively studied across the accelerator complex at CERN due to their important role in characterizing the beam and their complicated modeling. In recent years, this topic has been of particular interest for the LHC Injectors Upgrade (LIU) project, where a tight transverse emittance blow-up budget between the Proton Synchrotron Booster (PSB) and the Proton Synchrotron (PS) is imposed to assure the required beam brightness for the High Luminosity LHC (HL-LHC). In order to maintain a high brightness beam, any source of emittance blow-up along the PSB cycle needs to be identified and mitigated. While wire scanners have been mostly used at extraction energy in the PSB, they can also operate along the energy cycle. The scattering of the protons with the wire increases considerably at lower energies, leading to an overestimation of the beam emittance. In this contribution we present the most recent studies, focusing on precisely quantifying the blow-up created by the flying wire with measurements in an optimized set-up and compared to FLUKA simulations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS101  
About • paper received ※ 13 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS102 Linear and Non-Linear Optics Measurements in PS using Turn-by-Turn BPM Data 1114
 
  • P.K. Skowroński, M. Giovannozzi, A. Huschauer
    CERN, Meyrin, Switzerland
 
  For the first time, the optics of the CERN Proton Synchrotron (PS) was measured using turn-by-turn BPM data of forced betatron oscillations excited with an AC dipole. We report results of phase advance and beta beating measurements. Linear coupling was globally minimized along the machine by measuring and correcting coupling resonance driving terms. Finally, non-linear properties of the ring were probed looking at third and fourth order resonance driving terms and amplitude detuning.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS102  
About • paper received ※ 07 May 2019       paper accepted ※ 19 May 2019       issue date ※ 21 June 2019  
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MOPTS106 Barrier Bucket Studies in the CERN PS 1128
 
  • M. Vadai, A. Alomainy
    QMUL, London, United Kingdom
  • H. Damerau
    CERN, Geneva, Switzerland
 
  Part of the residual beam loss during the Multi-Turn Extraction (MTE) of fixed target beams from the CERN Proton Synchrotron (PS) can be attributed to kicker magnets switching while the beam is coasting with the main RF systems off before extraction. Generating a barrier bucket to deplete the longitudinal line density of the coasting beam during the kicker rise time can reduce these losses. Beam tests have been performed with an existing Finemet cavity in the PS, which is normally operated as a wideband feedback kicker. To drive the cavity, a beam synchronous waveform synthesizer based on programmable logic has been developed. It produces a pre-distorted signal which ideally results in a single period sinusoidal voltage pulse with programmable parameters at the gap of the cavity, once or multiple times per revolution. The modelling of the behavior of the power amplifier and the cavity is essential to achieve an anti-symmetric voltage pulse with little pre- and post-pulse ripple. The design of the beam-synchronous waveform generator is presented together with results from initial beam studies with the created barrier buckets in the PS.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS106  
About • paper received ※ 18 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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MOPTS107 Beam Manipulations With Barrier Buckets in the CERN PS 1132
SUSPFO120   use link to see paper's listing under its alternate paper code  
 
  • M. Vadai, A. Alomainy
    QMUL, London, United Kingdom
  • H. Damerau, S.S. Gilardoni, M. Giovannozzi, A. Huschauer
    CERN, Geneva, Switzerland
 
  A barrier bucket scheme is being considered to reduce losses during the Multi-Turn Extraction from the CERN Proton Synchrotron to the Super Proton Synchrotron for the fixed-target physics programme. For effective loss reduction, the extraction kicker has to be triggered during the gap at the time of the longitudinal barrier. Initial beam studies at injection energy and with low intensity beams allowed to fully qualify an existing wide-band cavity to generate one or multiple beam synchronous pulses per turn. Bunch-length stretching and shortening have been exercised with barriers moving in azimuth with respect to the beam. The encouraging results obtained at injection energy guided the implementation of a de-bunching manipulation at higher energy to move all bunches into a single barrier bucket. Beam measurements at a momentum of 14GeV/c, varying intensity and the width of the barrier, demonstrate that a quasi-constant longitudinal line density and an almost fully depleted gap can be achieved at highest intensities. The contribution summarises the results of the beam studies at high energy together with some observations related to the Multi-Turn Extraction.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS107  
About • paper received ※ 18 April 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS113 Sensitivity Analyses of All-Electric Storage Ring Designs 1148
 
  • M.J. Syphers, A. Narayanan
    Northern Illinois University, DeKalb, Illinois, USA
 
  Funding: This work supported by the National Science Foundation Grant 1623691.
Future searches of electric dipole moments (EDMs) of fundamental particles can require electrostatic storage rings operating at the particle’s "magic momentum" whereby spin precessions out of the plane of the particle motion would be governed in principle only by the presence of an EDM. An EDM search for the proton, for example, requires a momentum of approximately 700 MeV/c and thus implies a half-kilometer circumference, where relatively modest electric fields are assumed. As no all-electric ring on this scale has been constructed before, the ability to produce precise radial fields for establishing a central orbit and precise electrostatic focusing fields about that orbit requires attention. Results of initial investigations into the feasibility of designing a proper system and the sensitivities of such a system to placement, mis-powering errors and other requirements on realistic electrostatic elements will be presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS113  
About • paper received ※ 09 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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TUPTS109 Status of AC Dipole Project at Rhic Injectors for Polarized 3He, Update 2177
 
  • K. Hock, C.W. Dawson, H. Huang, J.P. Jamilkowski, F. Méot, P. Oddo, M.C. Paniccia, Y. Tan, N. Tsoupas, J.E. Tuozzolo, K. Zeno
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
An ac dipole will be used for the efficient transport of polarized 3He in the AGS Booster as it is accelerated to |Gγ|=10.5. The ac dipole introduces a coherent vertical beam oscillation which allows preservation of polarization through the two intrinsic resonances Gγ=12-νy and Gγ=6+νy resonances, by full spin flipping. The AGS Booster ac dipole will be tested with protons crossing the Gγ=0+νy intrinsic resonance, which has ac dipole requirements similar to polarized 3He crossing the Gγ=12-νy resonance, providing a convenient proof of principle. This paper gives a status of the project.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS109  
About • paper received ※ 13 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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TUPTS110 Scanning the AC Dipole Resonance Proximity Parameter in the AGS Booster 2179
 
  • K. Hock, H. Huang, F. Méot, P. Oddo, N. Tsoupas
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
An ac dipole system is installed in the AGS Booster in view of acceleration of polarized helion for RHIC and the eRHIC EIC. The amplitude of the vertical coherent oscillations induced by the ac dipole depends greatly on the resonance proximity parameter, δm, which is the distance between resonance tune and driving tune. Due to the non-zero momentum spread, particles with different momenta will have different value of δm. The rapid acceleration rate of the booster would cause δm to sweep, the amount of which would depend on the energy and the duration of the ac dipole cycle. These effects are simulated using zgoubi, which set a range of δm values suitable for both high spin flip efficiency and minimizing emittance growth, and the results of the simulations are discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS110  
About • paper received ※ 12 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPGW116 LHC Optics Measurement and Correction Software Progress and Plans 2773
 
  • R. Tomás, F.S. Carlier, J. Coello, J. Dilly, E. Fol, A. Garcia-Tabares, M. Hofer, E.H. Maclean, L. Malina, T. H. B. Persson, P.K. Skowroński, M.L. Spitznagel, A. Wegscheider, J. Wenninger
    CERN, Geneva, Switzerland
  • J.F. Cardona, Y. Rodriguez
    UNAL, Bogota D.C, Colombia
  • F.S. Carlier
    NIKHEF, Amsterdam, The Netherlands
  • D. Esperante Pereira, J. Fuster, D. Gonzalez-Iglesias
    IFIC, Valencia, Spain
  • R. Hoekstra
    KVI, Groningen, The Netherlands
 
  LHC Optics Measurements and Corrections (OMC) require efficient on-line software applications to acquire and analyze data and to compute the necessary corrections. During Run 2 various measurement and correction techniques have been merged to yield unprecedented optics quality, increasing the required number of steps to finalize the optics commissioning and the size of the software project. In turn, this calls for a higher level of automation, where machine learning techniques are being implemented. During the Long Shutdown 2 a large refactoring of the codes will be in place to improve performance, maintainability and extensibility. A description of the current status of the software and future plans is given.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW116  
About • paper received ※ 07 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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WEPRB107 The New 1-18 MHz Wideband RF System for the CERN PS Booster 3063
 
  • M.M. Paoluzzi, L. Arnaudon, V. Bretin, Y. Cuvet, J. Daricou, S. Energico, M. Haase, A.J. Jones, D. Landré, C. Rossi
    CERN, Meyrin, Switzerland
  • C. Ohmori
    KEK/JAEA, Ibaraki-Ken, Japan
 
  The LHC Injector Upgrade (LIU) project at CERN prepares the injectors to meet the requirements of the High Luminosity LHC. For protons, it includes the new Linac4, PS Booster (PSB), PS and SPS. Among the major changes concerning the PSB, the extraction energy increase from 1.4 GeV to 2 GeV and the higher beam intensity, made possible by the Linac4 together with the new charge exchange injection system into the PSB (2·1013 protons) strongly affect the RF system requirements. To deal with this more demanding beam operation, a new RF system was designed. It is based on modern magnetic alloy loaded cavities driven by solid-state amplifiers. Its wideband frequency response (1 MHz to 18 MHz) covers all the required frequency schemes. This new RF system has been produced in 2017 and 2018; installation is planned during 2019, the first year of Long Shutdown 2 (LS2) and commissioning foreseen in 2020. Most of the production and testing was outsourced to industry; parts acceptance, cavities assembly and pre-testing was done in-house. A quality assurance plan was established to achieve the required high reliability. This paper describes the procurement, production and testing strategies and methodologies. It also reports the achieved results, system performances and relevant statistics.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB107  
About • paper received ※ 26 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THXXPLM1 NUCLOTRON Development for NICA Acceleration Complex 3396
 
  • E. Syresin, N.N. Agapov, A.V. Alfeev, V. Andreev, A.A. Baldin, A.M. Bazanov, O.I. Brovko, V.V. Bugaev, A.V. Butenko, D.E. Donets, E.D. Donets, E.E. Donets, A.V. Eliseev, V.V. Fimushkin, B.V. Golovenskiy, E.V. Gorbachev, A. Govorov, E.V. Ivanov, V. Karpinsky, V. Kekelidze, H.G. Khodzhibagiyan, A. Kirichenko, V.V. Kobets, S.A. Kostromin, A.D. Kovalenko, O.S. Kozlov, K.A. Levterov, D.A. Lyuosev, A.A. Martynov, I.N. Meshkov, V.A. Mikhailov, V.A. Monchinsky, A. Nesterov, A.L. Osipenkov, D.O. Ponkin, S. Romanov, P.A. Rukojatkin, K.V. Shevchenko, I.V. Shirikov, A.A. Shurygin, A.O. Sidorin, V. Slepnev, A.V. Smirnov, G.V. Trubnikov, A. Tuzikov, B. Vasilishin
    JINR, Dubna, Moscow Region, Russia
  • A. Belov
    RAS/INR, Moscow, Russia
  • A.V. Philippov, V. Volkov
    JINR/VBLHEP, Dubna, Moscow region, Russia
 
  The Nuclotron is the basic facility of JINR used to generate beams of protons, polarized deuterons and protons, and multi charged ions in the energy range of up to 5.6 GeV/n. Polarized deuteron and proton beams were obtained at the intensity of 2×109 ppp and 108 ppp, respectively. The injection with RF adiabatic capture was used in two last Nuclotron runs where C6+, Xe42+, Kr26+ and Ar16+ ion beams were accelerated. The resonant stochastic extraction (RF knockout technique) was realized. The complex is now used for fixed target experiments with extracted beams and experiments with an internal target. In the near future, the Nuclotron will be the main synchrotron of the NICA collider facility being constructed at JINR. The installation in the Nuclotron of beam injection system from the Booster and of the fast extraction system in the Collider are required for its operation in the NICA complex. In the frame of the Nuclotron injection chain upgrade, a new light ion linac (LILac) for protons and ions will be built.  
slides icon Slides THXXPLM1 [10.806 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THXXPLM1  
About • paper received ※ 29 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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