Keyword: operation
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MOIPI1 1 MW J-PARC RCS Beam Operation and Further Beyond injection, simulation, resonance, experiment 1
 
  • H. Hotchi
    KEK, Tokai, Ibaraki, Japan
  • H. Harada, N. Hayashi, M. Kinsho, K. Okabe, P.K. Saha, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yamamoto, M. Yoshimoto
    JAEA/J-PARC, Tokai-mura, Japan
 
  The J-PARC RCS have recently established a 1 MW beam operation with low fractional beam loss of the order of 10-3. In this talk, our approaches to beam loss issues that we faced in the course of beam power ramp-up are reviewed. Our recent efforts to further beam power ramp-up beyond 1 MW are also presented.  
slides icon Slides MOIPI1 [2.210 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOIPI1  
About • Received ※ 04 October 2021 — Revised ※ 18 October 2021 — Accepted ※ 10 November 2021 — Issue date ※ 22 November 2021
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MOCC3 First Experience of Crystal Collimators During LHC Special Runs and Plans for the Future collimation, background, simulation, proton 12
 
  • M. D’Andrea, V. Avati, R. Bruce, M.E.J. Butcher, M. Deile, M. Di Castro, H. Garcia Morales, S. Jakobsen, J. Kašpar, I. Lamas Garcia, A. Masi, A. Mereghetti, D. Mirarchi, S. Redaelli, B. Salvachua, P. Serrano Galvez, M. Solfaroli Camillocci
    CERN, Geneva, Switzerland
  • B.S. Dziedzic, K.M. Korcyl
    IFJ-PAN, Kraków, Poland
  • Yu.A. Gavrikov
    PNPI, Gatchina, Leningrad District, Russia
  • K.H. Hiller
    DESY Zeuthen, Zeuthen, Germany
  • N. Turini
    UNISI, Siena, Italy
 
  Bent crystals can deflect charged particles by trapping them within the potential well generated by neighboring crystalline planes and forcing them to follow the curvature of the crystal itself. This property has been extensively studied over the past decade at the CERN accelerator complex, as well as in other laboratories, for a variety of applications, ranging from beam collimation to beam extraction and in-beam fixed target experiments. In 2018, crystal collimators were operationally used for the first time at the Large Hadron Collider (LHC) during a special high-beta* physics run with low-intensity proton beams, with the specific goal of reducing detector background and achieving faster beam halo removal. This paper describes the preparatory studies carried out by means of simulations, the main outcomes of the special physics run and plans for future uses of this innovative collimation scheme, including the deployment of crystal collimation for the High-Luminosity LHC upgrade.  
slides icon Slides MOCC3 [2.138 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOCC3  
About • Received ※ 03 October 2021 — Accepted ※ 22 November 2021 — Issue; date; ※; 13 January 2022  
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MOP02 Recent Improvements in the Beam Capture at Fermilab Booster for High Intensity Operation cavity, injection, booster, LLRF 23
 
  • C.M. Bhat, S. Chaurize, P. Derwent, M.W. Domeier, V.M. Grzelak, W. Pellico, J. Reid, B.A. Schupbach, C.-Y. Tan, A.K. Triplett
    Fermilab, Batavia, Illinois, USA
 
  Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
The Fermilab Booster is the oldest RCS in operation in the world. In current operations, it accelerates ~4.5E12ppp to 8 GeV at 15 Hz and will be upgraded to >6.7E12ppp at 20 Hz in the PIP-II era. Booster has 22 RF cavities with each capable of providing ~50 kV. These cavities are divided into two groups: A & B. In the tunnel, the cavities are cavities are placed in a BA, AB, ’ sequence. At injection, A & B cavities have anti-parallel RF phase which results in a net zero RF voltage on the beam. During beam capture, the RF voltage is increased adiabatically by decreasing the relative phase between them. At the end of beam capture, the feedback is turned on for beam acceleration. It is vital that for current operations and in the PIP-II era that these cavities are properly matched in both magnitude and phase to preserve the longitudinal emittance during the early part of the beam cycle and to offer full RF voltage on the beam. In this paper we describe the how the cavities are distributed and how the phases are measured with beam and then corrected and balanced. Data with high intensity beam capture is also presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOP02  
About • Received ※ 17 October 2021 — Revised ※ 16 November 2021 — Accepted ※ 22 November 2021 — Issue date ※ 28 January 2022
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MOP04 Status of the JAEA-ADS Superconducting LINAC Design linac, cavity, optics, emittance 30
 
  • B. Yee-Rendón, Y. Kondo, F. Maekawa, S.I. Meigo, J. Tamura
    JAEA/J-PARC, Tokai-mura, Japan
 
  The Japan Atomic Energy Agency (JAEA) is working in the research and development of an Accelerator Driven Subcritical System (ADS) for the transmutation of nuclear waste. To this end, JAEA is designing a 30-MW cw proton linear accelerator (linac) with a beam current of 20 mA. The JAEA-ADS linac starts with a Normal Conducting (NC) up to an energy of 2.5 MeV. Then, five Superconducting (SC) sections accelerate the beam up to 1.5 GeV. The biggest challenge for this ADS linac is the stringent reliability required to avoid thermal stress in the subcritical reactor, which is higher than the achieved in present accelerators. For this purpose, the linac pursues a strong-stable design that ensures the operation with low beam loss and fault-tolerance capabilities to continue operating in case of failure. This work presents the beam dynamics results toward achieving high reliability for the JAEA-ADS linac.  
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poster icon Poster MOP04 [0.764 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOP04  
About • Received ※ 30 September 2021 — Revised ※ 15 October 2021 — Accepted ※ 22 November 2021 — Issue date ※ 05 January 2022
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MOP07 Chromaticity Measurement Using Beam Transfer Function in High Energy Synchrotrons wakefield, network, synchrotron, octupole 46
 
  • X. Buffat, S.V. Furuseth, G. Vicentini
    CERN, Geneva, Switzerland
  • S.V. Furuseth
    EPFL, Lausanne, Switzerland
 
  Control of chromaticity is often critical to mitigate collective instabilities in high energy synchrotrons, yet classical measurement methods are of limited use during high intensity operation. We explore the possibility to extract this information from beam transfer function measurements, with the development of a theoretical background that includes the impact of wakefields and by analysis of multi-particle tracking simulations. The investigations show promising results that could improve the operation of the HL-LHC by increasing stability margins.  
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poster icon Poster MOP07 [0.716 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOP07  
About • Received ※ 04 October 2021 — Revised ※ 01 November 2021 — Accepted ※ 31 March 2022 — Issue date ※ 11 April 2022
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MOP09 HL-LHC Beam Dynamics with Hollow Electron Lenses electron, optics, emittance, simulation 59
 
  • P.D. Hermes, R. Bruce, R. De Maria, M. Giovannozzi, A. Mereghetti, D. Mirarchi, S. Redaelli
    CERN, Geneva, Switzerland
  • G. Stancari
    Fermilab, Batavia, Illinois, USA
 
  Each of the two proton beams in the High-Luminosity Large Hadron Collider (HL-LHC) will carry a total energy of 720 MJ. One concern for machine protection is the energy stored in the transverse beam tails, estimated to potentially reach up to 5% of the total stored energy. Several failure scenarios could drive these tails into the collimators, potentially causing damage and therefore severely affecting operational efficiency. Hollow Electron Lenses (HEL) were integrated in the HL-LHC baseline to mitigate this risk by depleting the tails in a controlled way. A hollow-shaped electron beam runs co-axially to the hadron beam over about 3 m, such that halo particles at large amplitudes become unstable, while core particles ideally remain undisturbed. Residual fields from e-beam asymmetries can, however, induce emittance growth of the beam core. Various options for the pulsing of the HEL are considered and are compared using two figures of merit: halo depletion efficiency and core emittance growth. This contribution presents simulations for these two effects with different HEL pulsing modes using the final HL-LHC optics, that was optimized at the location of the lenses.  
poster icon Poster MOP09 [0.970 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOP09  
About • Received ※ 06 October 2021 — Revised ※ 02 November 2021 — Accepted ※ 22 November 2021 — Issue date ※ 19 January 2022
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MOP19 Optimised Transverse Painting Schemes for the New 160 MeV H Injection System at CERN injection, simulation, emittance, resonance 118
 
  • E. Renner, S.C.P. Albright, F. Antoniou, F. Asvesta, H. Bartosik, C. Bracco, G.P. Di Giovanni, B. Mikulec, T. Prebibaj, F.M. Velotti
    CERN, Meyrin, Switzerland
 
  A major aspect of the LHC Injectors Upgrade (LIU) project at CERN is the Proton Synchrotron Booster (PSB) connection to the newly built Linac4 and the related installation of a new 160 MeV H charge exchange injection. This contribution presents the first operational experience with the new injection system and its flexibility of applying horizontal phase space painting to tailor different beams to the respective user-defined brightness targets. The presented measurement and multi-particle simulation results focus on the optimisation of the required transverse injection settings to reduce losses when producing high-intensity beams, i.e. for the ISOLDE experiment. In this context, feasibility studies towards applying numerical optimisation algorithms for improving and efficiently adapting the respective injection settings online are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOP19  
About • Received ※ 17 October 2021 — Revised ※ 19 October 2021 — Accepted ※ 20 November 2021 — Issue date ※ 12 April 2022
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MOP27 The Design and Implementation of Fast Machine Protection System for CSNS machine-protect, linac, DTL, power-supply 151
 
  • P. Zhu, Y.C. He, D.P. Jin, Y.L. Zhang
    IHEP, Beijing, People’s Republic of China
  • L. Wang, X. Wu, K. Xue
    IHEP CSNS, Guangdong Province, People’s Republic of China
 
  The high-quality of fast machine protection system(FPS) is one of the significant conditions for the stable and reliable operation of the Chinese Spallation Neutron Source (CSNS) accelerator. Based on the design concept of high availability, high reliability and high maintainability, we adopt the distributed architecture based on "high-performance Field Programmable Gate Array (FPGA) chip + Gigabit Transceiver with Low Power (GTP)+ VME bus read and write by real-time", which is demonstrated the superior performance to satisfy the requirements of the CSNS accelerator during commissioning and operation. The main design and implementation include: (1) develop diversity signal interface boards achieving a flexible interaction; (2) explore and realize protection strategies improving beam efficiency; (3) self-define and implement the creative and practical functions enhancing the robustness of the system, such as signal heartbeat monitoring, fail-safe mechanism, automatic reset, and so on. The CSNS accelerator fast machine protection system has been put into operation for nearly five years with strong operability and availability, thorough traversal and response time-consuming tests.  
poster icon Poster MOP27 [0.830 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOP27  
About • Received ※ 30 October 2021 — Revised ※ 24 October 2021 — Accepted ※ 05 November 2021 — Issue date ※ 11 April 2022
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TUIPI1 An Operationally Integrated Approach to the SNS 2.8 MW Power Upgrade target, cryomodule, proton, injection 156
 
  • J. Galambos
    ORNL, Oak Ridge, Tennessee, USA
 
  Funding: This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory.
The SNS accelerator consist of a 1 GeV H linac and an accumulator ring producing a 1.4 MW pulsed proton beam which drives a spallation neutron source. The Proton Power Upgrade project will double the power capability from 1.4 to 2.8 MW by increasing the linac energy 30% and the beam current about 50%. Equipment upgrades include new superconducting RF cryomodules and supporting RF equipment, upgraded ring equipment, and upgraded high power target systems. An important aspect of the upgrade is a gradual power ramp-up starting in 2022 in which new equipment is installed during maintenance outages as it arrives.
 
slides icon Slides TUIPI1 [3.795 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-TUIPI1  
About • Received ※ 03 October 2021 — Revised ※ 19 October 2021 — Accepted ※ 02 November 2021 — Issue date ※ 24 November 2021
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TUAC2 Impact of Power Supply Ripple on the Beam Performance of the Large Hadron Collider and the High-Luminosity LHC power-supply, experiment, dipole, betatron 170
 
  • S. Kostoglou, H. Bartosik, Y. Papaphilippou, G. Sterbini
    CERN, Geneva, Switzerland
 
  Harmonics of the mains frequency (50 Hz) have been systematically observed in the form of dipolar excitations in the transverse beam spectrum of the Large Hadron Collider (LHC) since the beginning of its operation. The power supply ripple, consisting of both fundamental and higher frequency components, is proven not to be the result of an artifact of the instrumentation systems with which they are observed. Potential sources of the perturbation have been identified through systematic analysis and experimental studies. Single-particle tracking simulations have been performed including a realistic power supply ripple spectrum, as acquired from experimental observations, to demonstrate the impact of such noise effects on beam performance.  
slides icon Slides TUAC2 [3.678 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-TUAC2  
About • Received ※ 04 October 2021 — Revised ※ 20 October 2021 — Accepted ※ 23 November 2021 — Issue date ※ 25 February 2022
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TUEC2 Operational Experience with Nanocrystalline Injection Foils at SNS injection, target, electron, ECR 176
 
  • N.J. Evans
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE- AC05-00OR22725 for the U.S. Department of Energy.
The Spallation Neutron Source (SNS) uses 300-400μ g/cm2 nanocrystalline diamond foils grown in-house at the Center for Nanophase Materials Sciences to facilitate charge exchange injection (CEI) from the 1 GeV H linac into the 248~m circumference accumulation ring. These foils have performed exceptionally well with lifetimes of thousands of MW·hrs. This contribution shares some experience with the operation of these foils during 1.4 MW operation, and discusses current operational concerns including injection related losses, foil conditioning, deformation, and sublimation due to high temperatures. The implications for the SNS Proton Power Upgrade are also discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-TUEC2  
About • Received ※ 17 October 2021 — Revised ※ 21 October 2021 — Accepted ※ 23 November 2021 — Issue date ※ 06 March 2022
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THAC1 Beam Instability Issue and Transverse Feedback System in the MR of J-PARC feedback, simulation, timing, extraction 208
 
  • T. Toyama, A. Kobayashi, T. Nakamura, M. Okada, M. Tobiyama
    KEK, Tokai, Ibaraki, Japan
  • Y. Shobuda
    JAEA/J-PARC, Tokai-mura, Japan
 
  In the J-PARC MR, according to the beam power upgrade over 100 kW, beam losses due to transverse collective beam instabilities had started to appear. We had introduced "bunch-by-bunch feedback" system in 2010. Continuing beam power upgrade over 250 kW again caused the transverse instabilities. We introduced "intra-bunch feedback" system in 2014. This has been suppressing those instabilities very effectively. But further beam power upgrade over 500 kW (2.6·10+14 ppp, 8 bunches) needs upgrade of "intra-bunch feedback" system. The current understanding of the transverse instabilities in the MR and the effect of the feedback system are presented from the view points of simplified simulation without the space charge effect and measurements. We are upgrading the system in two steps. The first step is "time-interleaved sampling and kicking" with two feedback systems. The second step is getting the sampling rate twice as much as the current rate, ~110 MHz. Details are explained using simulation.  
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slides icon Slides THAC1 [4.347 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-THAC1  
About • Received ※ 07 October 2021 — Revised ※ 28 October 2021 — Accepted ※ 22 November 2021 — Issue date ※ 07 January 2022
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THDC1 Slow Extraction Operation at J-PARC Main Ring extraction, timing, experiment, septum 219
 
  • M. Tomizawa, Y. Arakaki, T. Kimura, S. Murasugi, R. Muto, H. Nishiguchi, K. Okamura, Y. Shirakabe, Y. Sugiyama, E. Yanaoka, M. Yoshii
    KEK, Ibaraki, Japan
  • K. Noguchi
    Kyushu University, Fukuoka, Japan
  • F. Tamura
    JAEA/J-PARC, Tokai-mura, Japan
 
  A high-intensity proton beam accelerated in the J-PARC main ring (MR) is slowly extracted by using the third integer resonance and delivered to the experimental hall. A critical issue in slow extraction (SX) is a beam loss caused during the extraction. A dynamic bump scheme under an achromatic condition provides extremely high extraction efficiency. We have encountered a beam instability in the debunch formation process, which is estimated to be triggered by a longitudinal microstructure of the beam. To suppress this instability, the beam to the MR has been injected into the RF bucket with a phase offset. A newly developed RF manipulation, 2-step voltage debunch, has successfully pushed up the beam power up to 64.6 kW keeping a high extraction efficiency of 99.5%. A drastic beam loss reduction has been demonstrated in the beam test using a diffuser installed upstream of the first electrostatic septum (ESS1). 8 GeV bunched slow extraction tests for the neutrino-less muon to electron conversion search experiment (COMET Phase-I) have been successfully conducted.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-THDC1  
About • Received ※ 18 October 2021 — Revised ※ 22 October 2021 — Accepted ※ 22 November 2021 — Issue date ※ 03 December 2021
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