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2015/05/21 (Thursday)

0800 MC/Tower = 54/73 mK, G1/G2 = 318/295 mbar, Still = 8 mW / 1.14 K / 0.22 mbar, 1K Pot = 1.69 K / 13 mbar. Main bath = 1.6%.
0801 Fill LN cold trap Dewar.
0849 Main bath = 0.6%.
0902 Start LHe transfer
1000 Finish LHe transfer, main bath = 85.7%
1220 Tried DCRC33/50→DIB1/2 for a bit, with Side1/2 = -0.5/3.5 V, but interference pattern appeared every 10-30 seconds.
1400 Trying DCRC33/31/50→DIB1/2/3, and leaving the DIB1 FETs off. In this mode we can probably completely avoid the interference problem, and read all 12 phonon channels, and run with a bias. The only thing we sacrifice is charge readout on Side 1 - but can still use Side 2 charge channels for calibration. Will use +/- bias polarity so that holes are collected on the read out side, for better fiducialization.
1530 Find SQUID settings for DIB2 DCRC31:
DIB2 DCRC31 SQUID Bias [uA] Lockpoint [mV] Modulation Depth [Vpp]
A 78.13 4.83 .430
B 68.36 3.51 .400
C 74.22 3.48 .390
D 82.04 2.67 .480
1550 All SQUIDs zapped and set, QET biases set (using optimal values from DCRC50 IbIs curves), timing link set, all front-end gains at 50 and output gains at 7 for DIB1 and DIB2, 8 for DIB3. Note again that for DCRC31 (DIB2) the front-end gains seem to have no effect.
1610 Set charge biases to DIB1/2 = +4V / -4V (true values). All looks OK.
1700 Try flashing briefly with each LED individually. All four cause temperature increases, but for DIB1 LED2 and DIB2 LED1 the increases are significantly smaller.
1730 Bake detector overnight. With all LEDs flashing, tower warms to about 100 mK. Not very high.