LBNL-2020: LAT

Time: Tuesday, March 31 9am - 11am PDT

https://lbnl.zoom.us/j/818598127

Charge

• Summarize progress on all decisions on list:
  • Fixed ground shield, or not
    • Preliminary analysis posted here suggests not
  • Chile configuration: CD telescopes with "single-wafer optics tubes" 85 tube camera versus 2x19 (reference design) or 3x13 cryostat/telescope configuration
    • The sensitivity advantages of the 85 tube camera are compelling as described here and suggest that it should be pursued further. Critical steps for adopting it as the baseline design include:
      • Demonstrating that the silicon windows are robust and do not contribute significant loading/loss
      • Developing complete optical designs for the optics tubes
      • Developing mechanical designs for the optics tubes with realistic clearances and baffling
    • If 85 tube camera is adopted, the natural baseline would be 2 CD telescopes including possible use of CCAT-prime
  • Monolithic Mirrors
    • Update on development at meeting
  • South Pole: Telescope type & aperture & cryostat configuration (TMA, CD)
    • 6m or 5m aperture appears acceptable for delensing. Smaller than 5m aperture would degrade cluster science too severely.
    • TMA design appears promising, but less mature than CD. Studies are underway to assess whether it should be adopted as baseline design

• Write down paths to decisions not yet made
  • Summarize/update technical risks, R&D / simulation / engineering needs to retire those risks
  • Not just those associated with above decisions, but also other issues.
• Plan schedule of design reviews for these subsystems needed before CD1
  • Major decision review in May 2020

Agenda

Schedule 7 minutes or less per talk + 3 minutes questions (aim for 5 slides or less per talk)

• Status of developing the baseline LAT design & schedule for review (May 2020) - Mike Niemack (draft summary above)
• LAT system engineering & interface list review - Jim Grudzinski File:LAT-systemEngineeringInterfaceListReview.pdf
• CCAT and SO telescope status updates - Mike Niemack
• TMA design and monolithic mirrors - John Ruhl [1]
• TMA with different F# and analysis - Patricio Gallardo
• CD+TMA sidelobe comparison - Johanna Nagy and/or Ian Gullett
• CD Ground screen and sidelobe calculations - Patricio Gallardo
• SO 13-tube cryostat update – Mark Devlin
• Fermilab CD 85-tube cryostat development and TMA cryostat configurations - Don Mitchell
• Silicon window/lens update – Jeff McMachon's group slides

• Discussion: (Mike Niemack coordinating)
  • Filter considerations
  • Cryostat testing plan in lab (building on SO experience) and other topics
  • Summarize/update technical risks, R&D / simulation / engineering needs to retire those risks