Meeting 31 October 2017

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PRESENTATIONS

Simulation Update (Jixie)

6-point list and Geant4 model (Bogdan)


NOTES

SIMULATIONS

  • Discussion of Jixie's results based on Bogdan's model - note that at the time of the meeting prompt radiation results were not yet available and that target had not yet been implemented
  • Next steps for simulation studies
  • Prompt radiation - quantify damage (in mrem) with and without source
  • Need to know what the extra contribution from CPS is compared to target alone - if source contributes 10%, then could consider CPS optimized
  • Next step: optimization of shielding - can we make it thinner?
  • Specify radiation at pivot where detector (closest approach is 2 meters from the pivot) and materials are
  • Required filling out space with appropriate materials
  • Run flux of photons through target and see what get for pure photon source
  • Implement polarized target magnet


6-POINT LIST FOR PREPARING CPS TECHNICAL NOTE (p. 1-21)

  • Discussion of the list:
  1. Raster is 2mm x 2mm (requires polarized target rotation)
  2. Magnet pole is shaped to boost the B field to 3.2 T - length reduction, which leads to a better front shield and wedged absorber
  3. Central absorber of Cua has 1.9x better heat conductivity, 4.2x longer radiation length than the W-Cu(20%) alloy
  4. W-powder external shield (16g/cm^3 density) for better shielding
  5. Gradually "stepped" opening of the beam line for radiation leak reduction
  6. Shielding requirement logic: the radiation from the source should be a few times lower than from the photon beam interaction with the material of a polarized target
  • a very rough projection of radiation in the hall due to photon beam and target interaction based on RCS data from 2002 is presented - caveat is that the experimental conditions may not be the ideal comparison for the simulation, but may give ballpark guidance


GEANT4 MODEL (GEMC FRAMEWORK) SIMULATION (p. 22ff)

  • yellow volume on page 24: TOSCA model, rectangle, then eliminate all magnetic material
  • most trajectories of 11 GeV electrons are confined to volume - visually looks ok
  • working on heat deposition


COLLABORATION MEETING

  • The preliminary agenda is presented, fits generally after the Hall C meeting on Tuesday, waiting for Thia for confirmation if NPS meeting can start at 3pm


NEXT MEETING: TUESDAY, 22 NOVEMBER 2017 AT 3:00PM (EST)