2017/01/30 (Monday)

Previous Day

	Setup: DIB1/3/4 → 3.2 MHz filters → cables → nothing/33(2)/DCRC55(1)
0940	Tower/MC/Coldplate = 42.6/30.4/194.2 mK, Still = 1.2 K / 0.110 mbar, G1/G2 = 157/159 mbar, 1K Pot = 1.71 K / 34 mbar, Main bath = 41.0%. Boil off rate: close to slow mode.
0945	Fill LN2 cold trap.
1242	Trying new Tc method on DIB4 using DCRC1(55). Channels A and B are still unresponsive today, so we'll just look at DIB4 PC and PD.
	Set DCRC1 PC/PD QET biases to 10 μA. Both seem to be superconducting. Driver gains = 1x. Zero both channels.
1248	Tower = 42.3mK, apply 5 μW to MC heater.
1252	Tower = 48.6mK, apply 6uw to MC heater.
1255	Tower = 58.4mK, apply 7uw to MC heater.

1335	Applied 5-30 μW to MC heater and scanned through range of 40-91 mK.
	DIB4 PD behaved as expected; baseline changed by ~100mV with pulses seen during transition. DIB4 PC did not change more than 1mV through entire temperature scan, but DIB4 PB did show transition and pulses. Not sure what's going on here…

S101 Critical Temperatures
DIB chan	Side chan	SC → Transition [mK]	Transition → Normal [mK]	Normal → Transition [mK]	Transition → SC [mK]
DIB4 pB	Side 2 PF	70.8	71.2	76.1	73.8
DIB4 pD	Side 1 PF	70.8	71.9	74.2	73.2

1342	Tower back to 48.2mK and falling. DIB4PC responds to QET bias as expected. PIB4 PB is also responding to QET bias changes now too…
1351	Commence LHe transfer MB=34%
1430	With MB=47%, realize this is still the old “empty” dewar. At least I got a little more out of it. Grab a new dewar off the line and continue transfer.
1510	Cease LHe transfer MB=90.8%
1610	Tower temp = 41.9 mK.
	Turn off DCRC programs and power down DCRC1.
1613	Replace DIB4's gender changer and plug in all DCRCs in “standard” 2-sided configuration Setup: DIB1/3/4 → 3.2 MHz filters → cables → DCRC55(1)/33(2)/50(3)
	All DCRCs respond to telnet session. Enable DCRC3 in ODB and Turn on DCRC programs.
1619	Tower temp spiked to 800mK when DCRCs were powered on! Turn off DCRC programs and power down DCRC3.
1621	Temp still hovering around 800mK. Power down DCRC1, temp immediately begins to fall.
1624	Not sure what went awry there, DCRC1 had been operating normally before this power cycle. It's almost as though it's LEDs were on, though the ODB setting are all off.
1626	Tower temp back down to 143mK and falling. Going to try powering on DCRC1 again.
1630	Again, as soon as DCRC1 is powered, the tower temp rises to 800mK. Started up programs and turned DCRC1 LEDs quickly on and off again in ODB, but temp continued to rise.
1633	Fill LN2 cold trap.
1640	Power DCRC1, temp rises. Try turning on/off FET heater, test signals, LEDs, QET bias, SQUID bias using ODB. No effect.
1644	Try powering only DCRC1 on DIB1 with no timing links attached, still heats.
1647	DCRC1 on DIB4 does not cause heating, nor does DCRC3 on DIB1.
1650	DCRC1 on DIB1 still heats.
1651	DCRC1 on DIB3 does not heat. [image not archived: doubt.svg]
	It seems the only combination that causes this sudden heating is DCRC1 on DIB1. What the hell…
1739	Try once more after letting DCRC1 sit unpowered and unplugged for a while, but it still causes heating as before.

Note: On this day Nick did not try turning the 15V Power on or off on DCRC1. Everything here is consistent with the fact that for DIB1, the 15V Power needs to be on or else the tower will heat up.

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