Attendees: Rebecca, Shanjie, Jame, Eric, Alex,
Agenda:
- MFX photon dump sizing
- CXI KB mirror shielding
- Note Status: DRAFT circulated
- Burn through calculations
- XRT collimators
- Raytrace methodology
Discussion:
MFX photon dump sizing
- Alyssa has performed first pass for dump sizing: MFX-HE_BeamdumpPrelimResults_Draft1.docx
- Assumptions: KB locations IP ; sample is worst case reflector; mirrors are silicon, 3KeV+. Calculations will be run for various beam powers. Various wall burnthrough limits.
- Focused spot at IP is 1um. how far back (+Z) can the KB focus?
- what is the beam size (worst case) at the wall (after it diverges)?
- sheetrock burnthrough (ca sulfate)...or should we put layer of something else?
- aluminum?
- steel? can we assume steel can take 10W?
- optical laser burnthrough test?
- Need to check material of 2nd mirror substrate - ruthenium (more reflective– ~10%-25% bigger dump)
- Need to find out if there is a physical way to limit lower energy range (software interlocks have never been successfully implemented for this).
- will 46+ cm beam radius work in our space? Just barely–we have 483mm until MEC beampipe.
- shielding config for mec overlap?
- MEC pipe burnthough...
- Assuming 100um diamond window. is thicker ok? (required transmission?)
- if we have 200um - 20%transmission @5keV; still ok at higher energy
- Alex will think about what they really need for experiments
- Dump type - same as XPP??
- CXI KB mirror shielding
- Note Status: Shanjie circulated draft 10/29
- Info needed:
- check mech. drawings
- (maybe design changes coming...TBD after meetings with SACLA)
- Burn thru calculations
- Yiping - Air burn through 1D results: 50+m @18keV
- methodology and assumptions need to be vetted for solid material burnthrough calcs
- XRT collimators
- need upgraded L2Si version (2 locations)
- Yiping is looking into the air attenuation calc.
- air attenuation calculations need to be vetted - by whom??? Ask Yiping who he knows in the community.
- David asked Yiping to start working on it
- latest study on tunneling through air...papers: https://journals.iucr.org/s/issues/2016/01/00/xt5002/index.html
- someone from DESY can help?
- is our gas attenuator going to work?
- HXR atten needs upgrades to get to 2x pressure
- We should be concerned here?
- https://slac.sharepoint.com/sites/pub/Publications/BCS_Absorber_Diode_Based_BTM.pdf?CT=1614317177038&OR=ItemsView
- https://portal.slac.stanford.edu/sites/lcls_public/lcls_ii/acc_phy/technotes_lib/LCLS-II-TN-15-25.pdf
- https://portal.slac.stanford.edu/sites/lcls_public/lcls_ii/acc_phy/technotes_lib/LCLS-II-TN-15-24.pdf
- https://portal.slac.stanford.edu/sites/lcls_public/lcls_ii/acc_phy/technotes_lib/LCLS-II-TN-15-23.pdf
- air attenuation calculations need to be vetted - by whom??? Ask Yiping who he knows in the community.
- Collimator type and material
- reuse XTES design? or TBD
- Solid atten has thick Si
- operable to 25kEv (w/Si+SSt) - hack in XRT
- Diamond, Silicon, and Germanium planned for new Solid attenuator
- Power Slits - change blade
- BeO2 ceramic blades? TBD
- 10x more absorbant than Si??
- Scatter Slits
- No change - just limit insertion range
- Raytrace methodology
- MIRROR RANGES - where do we look up? +/-X; +/- Theta; hardstops;
- build tolerances into raytrace?
- Shanjie will send an example
- drawing method
- spreadsheet data?
- reference files
- RP requirements says you need to consider tolerance but doesnt prescribe how we do that