Telecon 20180620

Attending: Jamie, Brian, Tom, Shaul, Qi

Notes by : Qi

• Mechanical design of focal plane (.pdf) (Qi)
• 2-year, 4 detector, simulated maps available - next steps? (Kris)
• Report Writing (.pdf)
• Remaining key open areas: Thermal Design (JPL); Changing telecons to a lower cadence: two weeks?

Mechanical design of focal plane

• Jamie shared the experience with Bicep3 focal plane:
  • heat sink: gold frames and wires around perimeter of wafer. They found contact resistance is the main issue. Biggest thermal impedance comes from between gold and silicon; at 100mK, conductance is mainly through electrons, pushing harder does not help.
  • 4 clamps push down the wafers, but wafers can still slide; clamps don't short the instruments.
  • In theory, gold wires and bars play the role of RF shields.
• PICO has a preliminary design, which can be used to estimate the mass already; more details about how to mount wafers on frames are ongoing
• material of frame: copper vs invar? Jamie: invar has high capacity, large mount of magnetic material
• bump bonds should be straightforward on PICO time scale
• Karl knows the size of TDM, Qi to find out what Karl has concluded (AI)

Report writing

• page 4, section 3 Instrument is most relevant
• internal review
• by the end of August

Thermal design

• we don't have one yet, JPL is responsible.

No objection against changing the telecon cadence to 2 weeks.