Meeting 13 March 2018

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Result for backward shielding and optimization of shielding overall (Parker/Bogdan)

Result for effect of polarized target and CPS together (Jixie)

Target rotation and irradiation (Dustin)

Initial outline for a 10-page document (Tanja/Thia)

Outline for the 10-page document after discussion and including names for each section


* Action items for next meeting on Tuesday, 27 March at 3:00pm (EST):

  • FLUKA backward shielding and optimization (Parker/Bogdan)
  • Target rotation (Dustin/Donal)
  • Updates on sections and figures of the 10-page document (all, see section assignment)
  • Discussion FLUKA simulation
  • Comparison of dose rates from FLUKA and 2001 Geant3 simulations shows factor of ~2 discrepancy, which seems different from what was found in 2017 benchmarking studies
  • Comparison of dose rates for RCS experiment and FLUKA shows a factor of ~8 difference, where FLUKA is higher
  • comparison with GEANT3 shows a factor 2-3 difference, with GEANT3 higher than the measurement - this has been observed before. However, the difference between GEANT3-GEANT4-FLUKA seems much higher than earlier studies
  • Next: figure out where the observed discrepancies come from - choice of parameters in FLUKA?
  • Discussion about radiation studies for CPS with polarized target
  • Modifications to geometry were made (entrance flange, target nose with liquid helium, downstream beam pipe)
  • Comparison of doses for different configurations, e.g. pure photon beam+target, photon beam+CPS+target shows that the total dose remains the same - conclusion: CPS as source is negligible for total dose
  • Note that pure photon beam has higher dose compared to pure electron beam - this because have a higher photon flux at the target, factor ~30 higher
  • Also note that need to address "backward" lobe in the pure photon beam configuration as not physical - perhaps add another "black hole" at the back of CPS analogous to the "EM black hole" at the front that absorbs all charged particles. However, need to take into account backscattering.
  • Next: studies are complete, now need to work on presentation
  • Discussion about target rotation
  • Essential parameter for target design is the rotation speed
  • Approach: compared with heat load on regular target, can select the mechanically easiest design as long as design heat load is comparable to that from earlier experiment experience
  • Note that fast raster from GeN98 was slow (~1Hz?) covering a few cm^2
  • Next: check in more detail heat load of regular target
  • Discussion of CPS review document outline
  • Idea is to have a 10-page document describing the CPS concept and demonstrating that it is a feasible design to remove the condition on the WACS experiment
  • Optimizations of the outline were discussed and people were assigned to specific sections. Note that each section is limited to ~2 pages