Meeting 31 October 2017

PRESENTATIONS

Simulation Update (Jixie)

• Additional files sent after the meeting: Prompt Dose Rate 2D and 1D-Z

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)