THA —  Beam Dynamics, Simulations and Control   (26-Sep-19   08:30—10:00)
Chair: D. Winklehner, MIT, Cambridge, Massachusetts, USA
Paper Title Page
THA01 Precise Modelling and Large Scale Multiobjective Optimisation of Cyclotrons 284
  • J. Snuverink, A. Adelmann, C. Baumgarten, M. Frey
    PSI, Villigen PSI, Switzerland
  The usage of numerical models to study the evolution of particle beams is an essential step in the design process of particle accelerators. However, uncertainties of input quantities such as beam energy and magnetic field lead to simulation results that do not fully agree with measurements. Hence the machine will behave differently compared to the simulations. In case of cyclotrons such discrepancies affect the overall turn pattern or alter the number of turns. Inaccuracies at the PSI Ring cyclotron that may harm the isochronicity are compensated by 18 trim coils. Trim coils are often absent in simulations or their implementation is simplistic. A realistic trim coil model within the simulation framework OPAL is presented. It was used to match the turn pattern of the PSI Ring. Due to the high-dimensional search space consisting of 48 simulation input parameters and 182 objectives (i.e. turns) simulation and measurement cannot be matched in a straightforward manner. Instead, an evolutionary multi-objective optimisation with more than 8000 simulations per iteration together with a local search approach was applied that reduced the maximum error to 4.5 mm over all 182 turns.  
slides icon Slides THA01 [6.834 MB]  
DOI • reference for this paper ※  
About • paper received ※ 25 September 2019       paper accepted ※ 27 September 2019       issue date ※ 20 June 2020  
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Recent Developments of the Open Source Code OPAL  
  • A. Adelmann
    PSI, Villigen PSI, Switzerland
  After a general introduction of OPAL, I will introduce a set of new features available with version 2.0 [1]. All new features will be presented together with examples of ongoing research projects. In the OPAL-cyc flavour, a robust way of generating matched distributions with linear space charge is introduced. A new method for describing fixed field accelerators (FFAs) in a very general way will be shown. A new element TRIMCOIL can be used to correct for field-errors in cyclotrons and FFAs [2]. The OPAL was extended to allow the specification of multi objective optimisation problems, which are then solved with a built in NGSA-II genetic algorithm. A new feature SAMPLER allows you to setup and run random or sequential parameter studies and seamless utilisation of a vast number of computing cores. Future plans such as the new AMR-Solver for preceise neighbouring bunch simulations will presented.
[1] A. Adelmann et al., "OPAL a Versatile Tool for Charged Particle Accelerator Simulations", arXiv:1905.06654
[2] Matthias Frey et al., "Matching of turn pattern measurements for cyclotrons using multiobjective optimization", Phys. Rev. Accel. Beams 22, 064602, 2019
slides icon Slides THA02 [15.093 MB]  
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THA03 React Automation Studio: A New Face to Control Large Scientific Equipment 285
  • W. Duckitt, J.K. Abraham
    iThemba LABS, Somerset West, South Africa
  A new software platform to enable the control of large scientific equipment through EPICS has been designed. The system implements a modern tool chain with a React frontend and a PyEpics backend as a progressive web application. This enables efficient and responsive cross platform and cross device operation. A general overview of React Automation Studio as well as the system architecture, implementation at iThemba LABs, community involvement and future plans for the system is presented.  
slides icon Slides THA03 [276.798 MB]  
DOI • reference for this paper ※  
About • paper received ※ 13 September 2019       paper accepted ※ 26 September 2019       issue date ※ 20 June 2020  
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