Keyword: emittance
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MOAC3 Development of an Injection-Painted Self-Consistent Beam in the Spallation Neutron Source Ring injection, space-charge, simulation, target 7
 
  • A.M. Hoover
    UTK, Knoxville, Tennessee, USA
  • N.J. Evans
    ORNL RAD, Oak Ridge, Tennessee, USA
  • T.V. Gorlov, J.A. Holmes
    ORNL, Oak Ridge, Tennessee, USA
 
  A self-consistent beam maintains linear space charge forces under any linear transport, even with the inclusion of space charge in the dynamics. Simulation indicates that it is possible to approximate certain self-consistent distributions in a ring with the use of phase space painting. We focus on the so-called Danilov distribution, which is a uniform density, rotating, elliptical distribution in the transverse plane and a coasting beam in the longitudinal plane. Painting the beam requires measurement and control of the orbit at the injection point, and measuring the beam requires re- construction of the four-dimensional (4D) transverse phase space. We discuss efforts to meet these requirements in the Spallation Neutron Source (SNS) ring.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOAC3  
About • Received ※ 18 October 2021 — Revised ※ 21 October 2021 — Accepted ※ 22 November 2021 — Issue date ※ 02 March 2022
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MOP03 Longitudinal Emittance Measurements at PIP2IT cavity, MEBT, cryomodule, simulation 27
 
  • M. El Baz
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • J.-P. Carneiro, B.M. Hanna
    Fermilab, Batavia, Illinois, USA
 
  The PIP-II particle accelerator is a new upgrade to the Fermilab accelerator complex, featuring an 800-MeV H superconducting linear accelerator that will inject the beam into the present Fermilab Booster. A test accelerator known as PIP-II Injector Test (PIP2IT) has been built to validate the concept of the front-end of PIP-II. One of the paramount challenges of PIP2IT was to demonstrate a low longitudinal emittance at the end of the front end. Having a low longitudinal emittance is crucial in order to ensure the stability of the beam in the accelerator. We present a longitudinal emittance calculation at 14.3 MeV at the SSR1-8 cavity in the High Energy Transport line (HEBT). The signal is collected by a Fast Faraday Cup (FFC) at the end of HEBT and recorded by a high-bandwidth oscilloscope.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOP03  
About • Received ※ 02 November 2021 — Revised ※ 05 November 2021 — Accepted ※ 03 February 2022 — Issue date ※ 04 February 2022
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MOP04 Status of the JAEA-ADS Superconducting LINAC Design linac, cavity, optics, operation 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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MOP08 Recent Progress on Nonlinear Beam Manipulations in Circular Accelerators resonance, 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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MOP09 HL-LHC Beam Dynamics with Hollow Electron Lenses electron, optics, operation, 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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MOP11 Controlled Longitudinal Emittance Blow-Up for High Intensity Beams in the CERN SPS simulation, controls, synchrotron, extraction 71
 
  • D. Quartullo, H. Damerau, I. Karpov, G. Papotti, E.N. Shaposhnikova, C. Zisou
    CERN, Geneva, Switzerland
  • D. Quartullo
    Sapienza University of Rome, Rome, Italy
 
  Controlled longitudinal emittance blow-up will be required to longitudinally stabilize the beams for the High-Luminosity LHC in the SPS. Bandwidth-limited noise is injected at synchrotron frequency sidebands of the RF voltage of the main accelerating system through the beam phase loop. The setup of the blow-up parameters is complicated by bunch-by-bunch differences in their phase, shape, and intensity, as well as by the interplay with the fourth harmonic Landau RF system and transient beam loading in the main RF system. During previous runs, an optimization of the blow-up had to be repeated manually at every intensity step up, requiring hours of precious machine time. With the higher beam intensity, the difficulties will be exacerbated, with bunch-by-bunch differences becoming even more important. We look at the extent of the impact of intensity effects on the controlled longitudinal blow-up by means of macro-particle tracking, as well as analytical calculations, and we derive criteria for quantifying its effectiveness. These studies are relevant to identify the parameters and observables which become key to the operational setup and exploitation of the blow-up.  
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poster icon Poster MOP11 [1.121 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOP11  
About • Received ※ 15 October 2021 — Revised ※ 17 October 2021 — Accepted ※ 17 January 2022 — Issue date ※ 11 April 2022
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MOP13 Influence of Transverse Motion on Longitudinal Space Charge in the CERN PS space-charge, synchrotron, impedance, optics 83
 
  • A.J. Laut, A. Lasheen
    CERN, Geneva 23, Switzerland
 
  Particles in an intense bunch experience longitudinal self-fields due to space~charge. This effect, conveniently described by geometric factors dependent on a particle’s transverse position, beam size, and beam pipe aperture, is usually incorporated into longitudinal particle tracking on a per-turn basis. The influence of transverse betatron motion on longitudinal space~charge forces is, however, usually neglected in pure longitudinal tracking codes. A dedicated tracking code was developed to characterize the CERN PS such that an effective geometric factor of a given particle could be derived from its transverse emittance, betatron phase~advance, and momentum~spread. The effective geometry factor is then estimated per particle by interpolation without the need for full transverse tracking and incorporated into the longitudinal tracker BLonD. The paper evaluates this effect under conditions representative of the PS, where space~charge is dominant at low energy and progressively becomes negligible along the acceleration ramp. The synchrotron frequency distribution is modified and the filamentation rate is moreover increased, which could suggest a stabilizing space~charge phenomenon.  
poster icon Poster MOP13 [1.826 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOP13  
About • Received ※ 16 October 2021 — Revised ※ 22 October 2021 — Accepted ※ 12 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, resonance, 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, 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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MOP21 3D Symplectic Space Charge Implementation in the Latest Mad-X Version simulation, space-charge, experiment, optics 129
 
  • F. Schmidt, A. Latina, H. Renshall
    CERN, Meyrin, Switzerland
  • Y.I. Alexahin
    Fermilab, Batavia, Illinois, USA
 
  In 2018 as part of a collaboration between CERN and FNAL, the space charge (SC) implementation has been upgraded in a test version of MAD-X. The goal has been to implement the 3D symplectic SC kick together with a number of new features and benchmark it with earlier MADX-SC versions. Emphasis has given to the use of the Sigma Matrix approach that allows to extend MAD-X optics calculations. In the meantime, significant effort has been made to fully debug and optimize the code and in particular to achieve a speed-up of the simulations by a factor of 2. The code has been ported to the latest MAD-X version, the elaborated set-up procedures have been automated and a user manual has been written.  
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poster icon Poster MOP21 [1.236 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOP21  
About • Received ※ 05 October 2021 — Revised ※ 21 October 2021 — Accepted ※ 11 November 2021 — Issue date ※ 12 April 2022
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MOP23 Coupled Bunch Instabilities Growth in the Fermilab Booster During Acceleration Cycle booster, extraction, injection, acceleration 140
 
  • C.M. Bhat, N. Eddy
    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 an RCS with h=84 and gammaT =5.47 and, during standard operation it accelerates ~4.5E12ppBc from 400 MeV to 8 GeV at 15 Hz. The Booster is being upgraded to handle higher beam intensity >6.7E12ppBc and repetition rate of 20Hz. In the current mode of operation, we perform multi-turn beam injection and capture beam in h=84 system adiabatically. However, we have observed coupled bunch (CB) instabilities in the extracted beam. This issue is expected to worsen at higher beam intensities. In principle, for h=84 one expects 41 modes of oscillations contributing to these CB instabilities. Currently, we have a digital mode damper to mitigate prominent CB modes [1]. We would like to understand at what time in the beam cycle a particular mode is going to originate and how much it contributes at a different time of the cycle. In this regard, we have collected wall current monitor data from injection to extraction and looked for the start of a particular mode of CB instability and its growth for different intensities. This paper presents the results from this study and future plans to mitigate the CB instability in Booster.
[1] Nathan Eddy (private communications, 2020).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-MOP23  
About • Received ※ 17 October 2021 — Accepted ※ 22 November 2021 — Issue; date; ※; 22 January 2022  
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TUAC1 Self-Consistent Long-Term Dynamics of Space Charge Driven Resonances in 2D and 3D resonance, space-charge, 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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WEDC2 Acceleration of the High Current Deuteron Beam Through the IFMIF-EVEDA RFQ: Confirmation of the Design Beam Dynamics Performances rfq, MMI, simulation, proton 197
 
  • L. Bellan, L. Antoniazzi, M. Comunian, E. Fagotti, M.G. Giacchini, F. Grespan, M. Montis, A. Palmieri, A. Pisent, M. Poggi
    INFN/LNL, Legnaro (PD), Italy
  • T. Akagi, K. Kondo, K. Masuda, M. Sugimoto
    QST, Aomori, Japan
  • B. Bolzon, N. Chauvin
    CEA-IRFU, Gif-sur-Yvette, France
  • P. Cara, F. Scantamburlo
    IFMIF/EVEDA, Rokkasho, Japan
  • Y. Carin, H. Dzitko
    F4E, Germany
  • D. Jimenez-Rey, I. Podadera
    CIEMAT, Madrid, Spain
  • J. Marroncle
    CEA-DRF-IRFU, France
  • I. Moya
    Fusion for Energy, Garching, Germany
 
  The Linear IFMIF Prototype Accelerator (LIPAc) is a high intensity D+ linear accelerator; demonstrator of the International Fusion Material Irradiation Facility (IFMIF). In summer 2019 the IFMIF/EVEDA Radio Frequency Quadrupole (RFQ) accelerated its nominal 125 mA deuteron (D+) beam current up to 5 MeV, with >90% transmission for pulses of 1 ms at 1 Hz, reaching its nominal beam dynamics goal. The paper presents the benchmark simulations and measurements performed to characterize the as-built RFQ performances, in the low and high perveance regime. In this framework, the commissioning strategy with a particular focus on the reciprocal effects of the low-medium energy transfers lines and the RFQ is also discussed. In the last part of the paper, the future commissioning outlooks are briefly introduced.  
slides icon Slides WEDC2 [2.696 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-WEDC2  
About • Received ※ 05 October 2021 — Revised ※ 20 October 2021 — Accepted ※ 22 November 2021 — Issue date ※ 27 January 2022
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THDC2 Commissioning of the ESS Front End solenoid, MMI, LEBT, rfq 225
 
  • N. Milas, C.S. Derrez, E.M. Donegani, M. Eshraqi, B. Gålander, H. Hassanzadegan, E. Laface, Y. Levinsen, R. Miyamoto, M. Muñoz, E. Nilsson, D.C. Plostinar, A.G. Sosa, R. Tarkeshian, C.A. Thomas
    ESS, Lund, Sweden
 
  The European Spallation Source, currently under construction in Lund, Sweden, will be the brightest spallation neutron source in the world, when the proton linac driver achieves the design power of 5 MW at 2 GeV beam energy. Such a high power requires production, efficient acceleration, and transport of a high current proton beam with minimal loss. This implies in a challenging design and beam commissioning of this machine. The linac features a long pulse length of 2.86 ms at a relatively low repetition late of 14 Hz. The ESS ion source and low energy beam transport are in-kind contributions from INFN-LNS. Beam commissioning of this section started in September 2018 and continued until early July in 2019. This article presents highlights from a campaign of beam characterizations and optimizations during this beam commissioning stage.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-THDC2  
About • Received ※ 17 October 2021 — Revised ※ 20 October 2021 — Accepted ※ 22 November 2021 — Issue date ※ 01 December 2021
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THBC1 Beam Acceleration with the Upgraded Riken Heavy-Ion Linac optics, target, beam-transport, heavy-ion 231
 
  • T. Nishi, M. Fujimaki, N. Fukunishi, H. Imao, O. Kamigaito, T. Nagatomo, N. Sakamoto, A. Uchiyama, T. Watanabe, Y. Watanabe, K. Yamada
    RIKEN Nishina Center, Wako, Japan
 
  The performance of RIKEN heavy-ion linac (RILAC) has been upgraded with a new ECR ion source and superconducting linac booster (SRILAC). It is expected to play a major role in the synthesis of super-heavy elements (SHE), development of the technologies for production of medical radioisotopes, and as a powerful injector to RI Beam Factory. In this talk, I will report on the beam delivery for the SHE experiment that started in June 2020, especially on how to adjust the optics based on the measured beam emittance. We would also like to compare the simulated beam acceleration in RILAC with the measured emittance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2021-THBC1  
About • Received ※ 09 November 2021 — Revised ※ 16 November 2021 — Accepted ※ 23 November 2021 — Issue date ※ 27 November 2021
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