Keyword: resonance
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MOIPI1 1 MW J-PARC RCS Beam Operation and Further Beyond injection, operation, simulation, 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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MOP06 Resonance Compensation for High Intensity and High Brightness Beams in the CERN PSB sextupole, injection, brightness, octupole 40
 
  • F. Asvesta, S.C.P. Albright, F. Antoniou, H. Bartosik, C. Bracco, G.P. Di Giovanni, E.H. Maclean, B. Mikulec, T. Prebibaj, E. Renner
    CERN, Geneva, Switzerland
 
  Resonance studies have been conducted during the recommissioning of the CERN Proton Synchrotron Booster (PSB) following the implementation of the LHC Injectors Upgrade (LIU) project. In particular, resonance identification through so-called loss maps has been applied on all four rings of the PSB, revealing various resonances up to fourth order. In a second step, compensation schemes for the observed resonances were developed using a combination of analytical methods, experimental data and machine learning tools. These resonance compensation schemes have been deployed in operation to minimize losses for reaching high intensity and high brightness, thereby achieving the target brightness for the LHC-type beams.  
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poster icon Poster MOP06 [1.923 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOP06  
About • Received ※ 05 October 2021 — Revised ※ 17 October 2021 — Accepted ※ 22 November 2021 — Issue date ※ 27 November 2021
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MOP08 Recent Progress on Nonlinear Beam Manipulations in Circular Accelerators emittance, controls, extraction, experiment 52
 
  • F. Capoani, M. Giovannozzi
    CERN, Geneva, Switzerland
  • A. Bazzani
    Bologna University, Bologna, Italy
 
  In recent years, transverse beam splitting by crossing a stable resonance has become the operational means to perform MultiTurn Extraction (MTE) from the CERN PS to the SPS. This method delivers the high-intensity proton beams for fixed-target physics at the SPS. More recently, further novel manipulations have been studied, with the goal of devising new techniques to manipulate transverse beam properties. AC magnetic elements can allow beam splitting to be performed in one of the transverse degrees of freedom. Crossing 2D nonlinear resonances can be used to control the sharing of the transverse emittances. Furthermore, cooling the transverse emittance of an annular beam can be achieved through an AC dipole. These techniques will be presented and discussed in detail, considering future lines of research.  
poster icon Poster MOP08 [5.281 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOP08  
About • Received ※ 04 October 2021 — Revised ※ 05 November 2021 — Accepted ※ 13 December 2021 — Issue date ※ 11 April 2022
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MOP18 Injection Chicane Beta-Beating Correction for Enhancing the Brightness of the CERN PSB Beams injection, emittance, focusing, brightness 112
 
  • T. Prebibaj, S.C.P. Albright, F. Antoniou, F. Asvesta, H. Bartosik, C. Bracco, G.P. Di Giovanni, E.H. Maclean, B. Mikulec, E. Renner
    CERN, Meyrin, Switzerland
  • T. Prebibaj
    IAP, Frankfurt am Main, Germany
 
  In the context of the LHC Injectors Upgrade Project (LIU), the Proton Synchrotron Booster (PSB) developed an H charge exchange injection system. The four short rectangular dipoles of the injection chicane induce focusing errors through edge focusing and Eddy currents. These errors excite the half-integer resonance 2Qy = 9 and cause a dynamically changing beta-beating in the first milliseconds after injection. Using the beta-beating at the positions of two individually powered quadrupoles, measured with k-modulation, correction functions based on a model response matrix have been calculated and applied. Minimizing the beta-beating at injection allows the machine to be operated with betatron tunes closer to the half-integer resonance and therefore with larger space charge tune spreads. In this contribution the results of the beta-beating compensation studies and the impact on the achievable beam brightness limit of the machine are presented.  
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poster icon Poster MOP18 [1.322 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOP18  
About • Received ※ 04 October 2021 — Revised ※ 01 November 2021 — Accepted ※ 05 February 2022 — Issue date ※ 11 April 2022
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MOP19 Optimised Transverse Painting Schemes for the New 160 MeV H Injection System at CERN injection, simulation, operation, emittance 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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MOP20 Space Charge Resonance Analysis at the Integer Tune for the CERN PS space-charge, simulation, quadrupole, optics 124
 
  • F. Schmidt, F. Asvesta
    CERN, Meyrin, Switzerland
 
  In the context of the LHC Injectors Upgrade (LIU) project, a series of studies have been performed in order to better understand the beam brightness limitations imposed by resonances and space charge effects. Space charge simulations using the analytic (frozen) space charge solver as implemented in the MAD-X code conducted for the CERN Proton Synchrotron (PS) show that a particle approaching the integer tune of Qx = 6 demonstrates a resonant behavior. The analysis of the single particle transverse motion reveals the excitation of a second order resonance. The interplay of the space charge effect and the optics perturbation in the regime of the integer tune on this excitation was further investigated. The simulations were complemented with the analysis of the resonance driving terms coming from the space charge potential derived in a classical perturbative approach.  
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poster icon Poster MOP20 [5.934 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOP20  
About • Received ※ 05 October 2021 — Revised ※ 20 October 2021 — Accepted ※ 24 December 2021 — Issue date ※ 12 April 2022
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TUAC1 Self-Consistent Long-Term Dynamics of Space Charge Driven Resonances in 2D and 3D space-charge, emittance, simulation, synchrotron 160
 
  • A. Oeftiger, I. Hofmann
    GSI, Darmstadt, Germany
  • O. Boine-Frankenheim
    TEMF, TU Darmstadt, Darmstadt, Germany
 
  Understanding the 3D collective long-term response of beams exposed to resonances is of theoretical interest and essential for advancing high intensity synchrotrons. This study of a hitherto unexplored beam dynamical regime is based on 2D and 3D self-consistent particle-in-cell simulations and on careful analysis using tune spectra and phase space. It shows that in Gaussian-like beams Landau damping suppresses all coherent parametric resonances, which are of higher than second order (the "envelope instability"). Our 3D results are obtained in an exemplary stopband, which includes the second order coherent parametric resonance and a fourth order structural resonance. They show that slow synchrotron oscillation plays a significant role. Moreover, for the early time evolution of emittance growth the interplay of incoherent and coherent resonance response matters, and differentiation between halo and different core regions is essential. In the long-term behavior we identify a progressive, self-consistent drift of particles toward and across the resonance, which results in effective compression of the initial tune spectrum. However, no visible imprint of the coherent features is left over, which only control the picture during the first one or two synchrotron periods. An intensity limit criterion and an asymptotic formula for long-term rms emittance growth are suggested. Comparison with the commonly used non-self-consistent "frozen space charge" model shows that in 3D this approximation yields a fast and useful orientation, but it is a conservative estimate of the tolerable intensity.
HB’21 talk on "Effect of Space Charge on Bunch Stability and Space Charge Compensation Schemes" based on this APS PR-AB published contribution.
 
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slides icon Slides TUAC1 [2.836 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-TUAC1  
About • Received ※ 11 October 2021 — Revised ※ 04 November 2021 — Accepted ※ 05 November 2021 — Issue date ※ 23 November 2021
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