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2017/06/14 (Wednesday)

Status	Began warmup yesterday. Mixture has been pumped out of LN2 traps, which are currently warm and need to be cleaned. Fridge is open to dump through V3, V4, V1 and fridge valves. 1K Pot needle valve is open. He gas has been let into the cryostat vacuum jacket. Also some He gas in the IVC.
0910	Close all valves to He recovery
0915	G1 = 733 mbar, MC(Cernox) = 205 K (20 mW), Sorb = 250 K (max)
0920	MC is still warming slowly, extrapolating it looks like it won't hit 300 K until late tonight
0925	Close V4 to isolate the dump. Turn on 3He pump. Open V9 to connect pump outlet to dump. Open V6 to 13% to pump mix from fridge to dump.
0935	G1 down to 43 mbar, open V6 further
1015	Let about 680 mbar N2 gas into IVC. This is the pressure according to the mechanical gauge on the pump manifold. The Pfeiffer gauge reads 400 mbar. Note that the high-pressure mode on the Pfeiffer gauge reads too high when it is reading helium, see Dec 18 for example. But it reads closer to correct when it's N2 gas, at least in the 250-300 mbar range. (Now it's reading too low.)
1020	G2 (dump) = 789 mbar, G1 (fridge) = 0.3 mbar, both pretty flat. P1 (fridge) = 0.016 mbar and creeping down, but low enough. Stop pumping out fridge. Close still gate valve, condenser valve, V1, V3, and V6. Close V9 then turn off 3He pump. G2 (Dump) = 789.2 mbar, Pbarometric = 29.71 inHg, Dump pressure (adjusted) = 782.1 mbar
1030	Let long hose length (4 or 5 meters) of N2 gas into IVC vacuum jacket to improve conductivity, speed warming.
1035	Adjust LakeShore bridge settings to range 2 kOhm, excitation 632 uV, much more appropriate to the Cernox thermometer in this range. Reading is much more uniform, but somewhat lower than before, 193 K
1210	MC(Cernox) = 202.8 K. Currently rising about 6 K/hr. At that rate it will reach room temperature early tomorrow morning.
1225	Let 5 more long hose-lengths of N2 into cryostat vacuum jacket, for good measure
1330	MC(Cernox) = 210.2 K
1340	Open Trap 1 up to G1 volume. Pressure rises to >1 bar (!). Pump this out using scroll pump through V12a+speedi, V2, V7, V2a, V5a, valve to scroll pump.

1346	Investigate non-functioning TES channels (DIB3 PA, DIB4 PA). Now that the detector is warming up, we should be able to measure ~ MΩ resistance from one TES bias/return channel to another, unless a channel has both of it's detector wirebonds broken.

DIB	+	-	R (Ω)
3	PA bias	PA ret	84
3	PA bias	PB bias	620k
3	PA bias	PC bias	780k
4	PA bias	PA ret	79
4	PA bias	PB bias	1.06M
4	PA bias	PC bias	1.83M
4	PA bias	PD bias	19M

	These results indicate that the broken channels do not have both bias and return wirebonds broken. It could be the case that a single bond is broken, but since they're shorted by the 20mΩ shunt, its not possible to tell this way. Furthermore, the PA bias/return values indicate the circuit is intact at least up to the shunt resistors (i.e. not a stripline break).

1400	Thermostat reading/setpoint=71.8F/73F, Lab In/humidity = 23.7C/40%
1400	Pumped LN2 Cold Trap 1 down to 3 mbar.
1405	Checked LN2 Cold Trap 2: about 13 mbar in it. Pump this one out too.
1425	Put LN2 cold traps back in bath and fill with LN2 in preparation for cleaning mixture.
1700	MC(Cernox) = 228.4 K. IVC = 630 mbar (Pfeiffer). The trend looks like maybe it will be 285 K (around 50 F) by morning.