1 / 14

ISIS Upgrade Modelling

ISIS Upgrade Modelling. Dean Adams On behalf of STFC/ISIS C Warsop, B Jones, B Pine, R Williamson, H Smith, M Hughes, A McFarland, A Seville, I Gardner, R Mathieson, S Payne, A Pertica, S Fisher, S Jago, J Thomason and Imperial College London J Pasternack.

bette
Download Presentation

ISIS Upgrade Modelling

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ISIS Upgrade Modelling Dean Adams On behalf of STFC/ISIS C Warsop, B Jones, B Pine, R Williamson, H Smith, M Hughes, A McFarland, A Seville, I Gardner, R Mathieson, S Payne, A Pertica, S Fisher, S Jago, J Thomason and Imperial College London J Pasternack PASI , Friday 5th April 2012, RAL

  2. A 0.5 MW ISIS • Replace old 70 MeV Linac with 180 MeV version and upgrade injection beam lines and ring injection region. • Synchrotron Space charge limit scales as β2γ3 hence 80 to 180 MeV ≈ factor of 2.60 so output scales from 0.2 to 0.5 MW. • Presentation focuses on Ring Studies/Modelling: Transverse and longitudinal dynamics, injection, foils, magnets, RF and beam loss control.

  3. H- h. & v. sweeper magnets Injection Scheme stripping foil beam dump p+ M3 M1 M2 M4 • H- charge exchange injection over 500 turns on either falling rising or symmetric point of main magnet field. • Horizontal painting using dynamic injection bump (50-200 π mm mrad) • Vertical painting via sweeper magnets (50-200 π mm mrad). • Longitudinal paint ±0-1.3 MeV using Linac injection energy and Ring RF bucket frequency errors. Chopped at ± 110° wrt Ring RF phase. inner radius 4  pulsed ferrite, magnets (0.17 T, 45 – 55 mrad, 26,000 A in ~500 s)

  4. 1D studies • In house 1D code with longitudinal space charge. • Paint chopped beam (±110 °) using injection energy and ring RF bucket energy offset. • Use a dual harmonic volts system • High bunching factor , transverse stability by Keil-Schnell-BoussardCriterion (KSB) for bunched beams < 1

  5. 3D Studies Centred around use of ORBIT code (Fermilab, SNS). Version used here modified to include RF Offsets and Acceleration. Models: Injection/Acceleration with Ramping Tunes and Harmonic Envelope Errors. Machine apertures and collimators (Beam Loss). ‘3D space charge’ routine. Foil scattering. Run in parallel environment using ~ 2M macro particles. Produces: 6D phase space, emittance evolution, beam losses, foil hits, beam moments etc

  6. ORBIT Injection Studies Dynamic injection bump 3D Injection painting simulated. Produce beam with maximum emittance300 π mm mrad (un-normalised) Centroid painting roughly constant at 100 π mm mrad. 6D phase space at end of injection H and V 99% emittance evolution

  7. Foils Foil:3.3σ RMS width ORBIT model simulates foil hits In-house codes simulates striping efficiencies and foil temperatures. Injected Beam p (200 µg/cm2 carbon (as per JPARC) >99.6% stripping efficiency H- H0 ~ 3.5 re-circulations/injected proton, 1322 K on hottest point. Re-circulating beam ANSYS modelling agrees well. Double foils studies in progress Pixel temperatures reach steady state after 10 pulses, 0.2s Temperature Per Pixel

  8. Injection Straight Magnets Injection Magnets modelled using Opera Injection dipole, peak field 0.165 T @ 26000 A Blue zone 0.125% uniformity Particle tracking through complex fringe fields

  9. steel MARS modelling (below) indicates ~ 5x increase in activation between 70 and180 MeV Beam Losses and Activation Fe mSv/h Cu concrete graphite ORBIT simulation (right) predicts < 1 % beam loss mainly located on collimators. Kinetic energy, MeV Loss, Horizontal, Vertical, Total

  10. Tune Space ORBIT used to model incoherent tune spread over injection and acceleration F=1 KV, 2 WB mode max

  11. Working point studies Other working points under investigation to avoid instabilities, half integer, head-tail SET code developed in-house, 2D particle tracker with images. Raising Vertical tune leads to loss of dynamic aperture (right) and coupling resonances Nominal design tune Lowering Vertical Tune below half integer leads to sextupole resonance driven by images. 3D version of SET (SET3D) in development to complement ORBIT studies

  12. Study of Loss Mechanisms • High intensity “space charge limit”: half integer resonance New Storage Ring Mode Experiments Halo Experiment Transverse Profiles • Simplified 2D beam dynamics • Drive beam onto coherent resonance • Loss observations as expect • What causes growth? • Simulations and theory suggest parametric halo • Measuring halo development in new experiments Experiment Simulation (Y,Y) Drive phase 1 Loss vs Intensity Predicted Resonance Measured Loss (Y,Y) (Y,Y) Drive phase 2 • Giving a deeper understanding of main loss mechanism • Confirmation of codes and methods used in new designs

  13. Diagnostics Electron Clouds Multi Channel Profile Monitor CST Stripline (monitor/kicker) ANSYS – HFSS Software

  14. Summary • Installing a new 180 MeV linac could increase ISIS power to ~ 0.5 MW • Looks technically challenging but studies have shown no ‘show stoppers’. • A variety of modelling software for beams and hardware used: ORBIT, in-house foil code, ANSYS, Opera, CST, SET (in-house) and HFSS • 3D beam code SET3D in development to benchmark against ORBIT. • Feasibility study almost complete. Report finalised in ~ 3 months.

More Related