Author: Cavanagh, H.V.
Paper Title Page
TUC2C1 Beam Physics Simulation Studies of 70 Mev ISIS Injector Linac 97
 
  • S.A. Ahmadiannamin, H.V. Cavanagh, S.R. Lawrie, A.P. Letchford
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
 
  The ISIS neutron spallation source is a pioneering research infrastructure in the field of high intensity accelerator physics, catering to scientific users. Comprising a 70 MeV injector linac and an 800 MeV Rapid cycling synchrotron with two beam targets, this facility has witnessed significant upgrades in recent years, leading to enhanced transmission efficiency. Further optimization efforts are underway to ensure continuous improvement. This article focuses on beam physics simulation studies conducted on the current ISIS linac, aiming to gain a deeper understanding and analysis of various phenomena observed during routine operations and accelerator physics experimentation. By examining these phenomena, valuable insights can be obtained to inform the future development of high efficiency injector of ISIS-II.  
slides icon Slides TUC2C1 [6.467 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC2C1  
About • Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 13 October 2023
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TUA4C1 Recent Progress in Loss Control for the ISIS High-Intensity RCS: Geodetic Modelling, Tune Control, and Optimisation 153
 
  • H. Rafique, E.K. Bansal, H.V. Cavanagh, C.M. Warsop
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
 
  ISIS operates a high intensity 50 Hz rapid cycling synchrotron (RCS), accelerating up to 3 x 1013 protons from 70 to 800 MeV. Protons are delivered to one muon and two neutron targets over two target stations, totalling 0.2 MW of beam power, enabling around 1000 experiments for approximately 3500 users a year. Minimisation of beam loss and optimisation of its control are central to achieving the best facility performance with minimal machine activation. We summarise recent work aimed at improving loss control in the RCS. Using geodetic survey data we aim to develop lattice models with realistic magnet alignment errors in cpymad. Building on recent measurement campaigns a new and improved system of tune control has been developed and verified using enhanced lattice models with cpymad. More rigorous and quantitative measures of beam loss have been implemented in graphical user interfaces (GUIs) using the QT GUI toolkit python interface PyQT5, and streaming data using the messaging protocol MQTT, in order to optimise loss control.  
slides icon Slides TUA4C1 [6.044 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA4C1  
About • Received ※ 28 September 2023 — Revised ※ 13 October 2023 — Accepted ※ 16 October 2023 — Issued ※ 29 October 2023
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THA1I2 High-Intensity Studies on the ISIS RCS and Their Impact on the Design of ISIS-II 331
 
  • R.E. Williamson, D.J. Adams, H.V. Cavanagh, B.S. Kyle, D.W. Posthuma de Boer, H. Rafique, C.M. Warsop
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
 
  ISIS is the pulsed spallation neutron and muon source at the Rutherford Appleton Laboratory in the UK. Operation centres on a rapid cycling proton synchrotron (RCS) that accelerates 3·1013 protons per pulse from 70 MeV to 800 MeV at 50 Hz, delivering a mean beam power of 0.2 MW. As a high-intensity machine, research at ISIS is predominantly focused on understanding, minimising and controlling beam-loss, which is central to sustainable machine operation. Knowledge of beam-loss mechanisms then informs the design of future high power accelerators such as ISIS-II. This paper provides an overview of the R&D studies currently underway on the ISIS RCS and how these relate to ongoing work understanding and optimising designs for ISIS-II. In particular, recent extensive investigations into observed head-tail instabilities are summarised.  
slides icon Slides THA1I2 [10.825 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THA1I2  
About • Received ※ 01 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 18 October 2023
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THBP24 RCS and Accumulator Rings Designs for ISIS II 519
 
  • D.J. Adams
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  • H.V. Cavanagh, I.S.K. Gardner, B.S. Kyle, H. Rafique, C.M. Warsop, R.E. Williamson
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
 
  ISIS is the spallation neutron source at the Rutherford Appleton Laboratory in the UK, which provides 0.2 MW of beam power via a 50 Hz, 800 MeV proton RCS. Detailed studies are now underway to find the optimal configuration for a next generation, short-pulsed neutron source that will define a major ISIS upgrade, with construction beginning ~2031. Determining the optimal specification for such a facility is the subject of an ongoing study involving neutron users, target and instrument experts. The accelerator designs being considered for the MW beam powers required, include proposals exploiting FFA rings as well as conventional accumulator and RCS rings. This paper summarises work on physics designs for the conventional rings. Details of lattice designs, injection and extraction systems, correction systems as well as detailed 3D PIC simulations used to ensure 0.1% losses and low foil hits are presented. Designs for a 0.4 to 1.2 GeV RCS and 1.2 GeV AR are outlined. Work on the next stages of the study are also summarised to benchmark and minimise predicted losses, and thus maximise the high intensity limit of designs.  
poster icon Poster THBP24 [3.231 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP24  
About • Received ※ 28 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 22 October 2023
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THBP59 Tomographic Longitudinal Phase Space Reconstruction of Bunch Compression at ISIS 625
 
  • B.S. Kyle, H.V. Cavanagh, A. Seville, R.E. Williamson
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
 
  ISIS is an 800 MeV, high intensity, rapid-cycling synchrotron (RCS) used as a driver for a spallation neutron and muon spectroscopy (¿SR) facility. The intensity-limited beam and RCS operation at ISIS poses significant challenges, with non-adiabatic acceleration and space charge forces resulting in distortions to the Hamiltonian longitudinal dynamics. Effective modelling of the machine and benchmarking of models with beam measurements is essential both to improving machine performance, and to the development of the proposed ISIS II facility. The tomographic principle is a well-established tool for the reconstruction of the longitudinal phase space (LPS) of synchrotron beams. Is it operationally desirable for the ISIS accelerator to provide longitudinally compressed proton beams for ¿SR instrumentation. A new bunch compression scheme has been developed and validated using tomography. A reconstruction of the LPS of the ISIS high-intensity proton beam is presented, along with accompanying benchmarking measurements and beam physics simulations.  
poster icon Poster THBP59 [0.907 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP59  
About • Received ※ 01 October 2023 — Revised ※ 09 October 2023 — Accepted ※ 20 October 2023 — Issued ※ 25 October 2023
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