slide 6 Indium conductivity value between literature value and Bill's number are different by factor of x500
slide 6 For 1.8e-5 and 1.44 e-7, units are W/cm K
slide 7 Thermal conductivity goes as 1/t^2 at low temp. Extrapolated to 100 mK using data points from Sladek
slide 7 Assuming thermal conductivity from electron only - Phonon contribution will only add
slide 8 Using Sladek's value, 10 mW of loading will change temperature by 6 mK
slide 9 Indium bump bond has lower thermal conductivity. 9.9e-7 W/cm @ 100 mK - This means 20 uW of loading will increase FP temperature by 8mK
slide 9 Jacques asked “Where do you have cooling power requirement?”, Qi answered “requirement not stated in this slide”
slide 9 Toki asked: “what is expected optical load on focal plane?”, Qi answered “I don't know” Karl may know?
slide 9 Tom “~20 uW at focal plane is reasonable”
slide 9 Roger - This (indium bump bond) will work okay. We need to work on how we explain it. Talk about strategy to build proto-type and test
slide 9 Tom - We could also design focal plane with ribbon bond to further mitigate this issue
slide 9 Kris - If the bonding was not enough there is room to put gold wires
slide 9 Roger - Through wafer via is used in PIPER. Are there any thermal problem? PIPER did lab testing. So far no major problem. Paper on this is not out yet. Test was done @ 100 mK
slide 9 Roger - We should point to PIPER as existing proof of working focal plane with similar configuration.
slide 9 Jacques - Are there write up on estimates on mass on cold stage & requirement on cooling power for the focal plane?
slide 9 Toki - There is mass estimate at end of Qi's slide
slide 9 Roger - JPL have thermal engineer working on this
slide 9 Jacques - We should write down Write mass and cooling power requirement of the coldest stage