Page History

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• 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
concrete
• • wall burnthrough limits.
• We have a preliminary size based on single pulse damage only but we need to know load from steady state
• • sheetrock burnthrough...or should we put layer of something else
?
• Concrete wall burnthrough calc for XPP. held up...we need help with assumptions/calc check
more info needed on KBs: substrate coating, focal length range

• • ?
    • aluminum?
  • Need to check material of 2nd mirror substrate
  • 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.
• focal length ~4m?
substrates?
• 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
• 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
  • 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