Telecon 20171205

Attending: Kris, Tom, Roger, Qi, Karl, Shaul, Brian

Notes by : Karl

• New sun shields, new alpha/beta? (JPL, UMN)
  • Last Week's Presentation (.pdf)
  • (.jpg)
• Focal plane V3.0 (Karl)
  • V3.0 status (.pdf)
• Update from JPL

New sun shields, new alpha/beta? (JPL, UMN)

• high angle tulip shields.
• primary protected.
• possible adjustments to alpha 30 or 35

Focal plane V3.0 (Karl)

• 40K primary and 0.07% emissivity.
• a 10% margin is included in these numbers given to the science team, just so they see less fluctuations.
• Shaul: option to increase FP size and number bolos by 2x. Keep this in mind.
  • Limits currently are data rate, see main imager wiki: posting/datavolume
    • 15k bolos give 3 Tb/day but DSN for 4 hours is 2 Tb/day
  • Kris: this is a stiff constraint for 10 yrs in future. Planck saw same type of limits evaporate during their planning.

Update from JPL

• Roger: Wiring and thermal load w/ Chris Paine. TDM and FDM.
  • FDM, has few wires to mK. More complicated warm readout. (Shaul: more power, yes. not necessarily more complicated. )
    • Power usage 15k bolos – 375 W for FDM
  • TDM, fewer wires. simpler warm readout
  • calculating heat load on mK from heat conduction and detector dissipation.
    • dissipation < 1 uW. not a problem.
  • wire count
    • x64 – 1850 wires (TDM), with 350 mK buffer stage, few - 50 uW load on mK.
    • x128 – 1140 wires, 3-30 uW load.
  • Next step, starting on FDM.
  • Peter Day is detector Team X partner. Typically supportive of aggressive stance.
• Brian: Joelle's model given to thermal analyst
  • from him:
    • Just satellite drifting passively: space craft 260 K, primary 31 K.
    • Adding heat sources, coolers, etc. to refine numbers.
    • Shaul: need inputs to Goddard for ADR design. Timeline?
      • Tom: need this by end of this week.

Team X is December 19.