| 1140 | Electrical check at 77K on DIB3: good except Feedback C is 31 kΩ and unstable, should be 7-9 kΩ. Bad because this is a connected Side1 channel, Side1pA. Check cross-channel resistances: >10 GΩ except A-C is 30 MΩ. That's Side2 to Side1. But A-B is Side2-Side2, so it should be lower than A-C, and B-C should be about the same as A-C. So maybe QETB is not connected at the detector. That's Side2pA, so that would be bad for biasing purposes. |
| 1155 | Electrical check at 77K on DIB4: good except short from qI FET gate to chassis, not relevant to this run. Cross-channel checks show continuity - pattern is a little odd but there's continuity. Lowest cross-channel is A-B (side2-side2) at 2 MΩ. |
| 1205 | Electrical check at 77K on DIB1: all good. Cross-channel checks show, at least from B to each of the others. |
| | so the biggest concerns are:
DIB3pC (Side1pA) Feedback has somewhat higher resistance than it should, could be bad pin at SQUET
DIB3pB (Side2pA) may not be connected at the detector, problem for biasing (but hard to say whether it's connected or not) |
| 1210 | Double-checked DIB3, now the iffy Feedback C reads fine. Should check phonon-related DIB3 connections again, see if they stay stable. Also cross-channel checks look OK now, at least A-C and B-C have continuity. |
| 1225 | Stop pumping IVC with turbo and start leak detector on IVC. Background leak = 500 pbarL/s. |
| 1230 | Leak detector on IVC = 640 pbarL/s |
| 1235 | Begin blowing out LN2. Main bath (G3) = 460 mbar above 1atm. |
| 1235 | Leak detector on IVC = 640 pbarL/s |
| 1240 | LD = 640 pbarL/s. Main bath = 466 mbar. |
| 1250 | LD = 620 pbarL/s. Main bath = 454 mbar. |
| 1251 | Main bath pressure starts falling |
| 1300 | LD = 2300 pbarL/s. Main bath = 155 mbar.
LD climbing… hits 20,000 pbarL/s |
| 1305 | LD = 6000 pbarL/s. Main bath = 140 mbar. Not sure why leak is coming back down. |
| 1310 | LD = 1200 pbarL/s. Main bath = 125 mbar. Stop pressurizing main bath. |
| 1310 | Leak signal rises again after stopping the He pressure. Don't know why. Climbs up to around 100,000 pbarL/s |
| 1320 | LD = 130,000 pbarL/s. |
| 1325 | Start pumping main bath with scroll pump. LD goes down. |
| 1330 | LD = 5,000 pbarL/s. Main bath pumping out slow, still around 0.4 bar. I think there's still LN in there (He cylinder was low). |
| 1330 | LD = 1400 pbarL/s.
Stop pumping out main bath. Restart LN2 blowout. |
| 1335 | Oops - I think the blowout was finished after all. The problem was that I didn't disconnect the hose from the LN2 transfer tube and insert a stopper. Dumb. |
| 1340 | Start pumping main bath with scroll pump. Leak falls. |
| 1350 | LD = 980 pbarL/s. Main bath = 0.45 mbar. |
| 1350 | Pump on IVC with turbo pump for a bit, try to get the leak background lower. Then close it again. |
| 1355 | LD = 670 pbarL/s. Main bath = 0.22 mbar. |
| 1355 | Try squirting He around stripline tube elbow. Causes increase in leak signal, around 700→800 pbarL/s. |
| 1400 | Pump out 1K Pot with scroll pump |
| 1400 | Close scroll pump valve.
Let 1 hose-length of He into IVC through vent. Main bath 0.5→1.6 mbar. Leak increases, 650→850 pbarL/s |
| 1405 | Let 1 more hose-length of He into IVC through vent. Main bath →3.0 mbar. Leak increases, 870→1100 pbarL/s |
| 1420 | Fill main bath with N2 gas. (Also pump IVC with turbo pump to bring leak baseline down.) LD base winds up at 720 pbarL/s after closing off turbo again. |
| 1430 | Squirt a blast of He gas down the LN2 transfer tube. Leak 720→1400 pbarL/s |
| 1435 | Raise transfer tube ~1 cm, then do another He squirt. Leak 1610→1630 pbarL/s |
| 1435 | Push transfer tube down again then squirt a blast of He gas down. Leak 1610→2700 pbarL/s |
| | As on March 15 it looks like there must be a leak in one of the lower IVC seals. Maybe not as bad as then, but in this run it's less tolerable because superfluid He films on the detector would cause phonon noise. |
| | Looks like we need to warm up. |
| 1450 | Let 8.6 mbar He transfer gas into IVC. |
| 1500 | Disconnect vacuum manifold from IVC port then connect to cryostat vacuum jacket port, then pump out line with scroll pump. |
| 1505 | Let 100 mbar N2 gas into vacuum manifold. Then open cryostat vacuum jacket valve to let this into the vacuum jacket. |
| 1510 | MC(Cernox) = 82.2 K, Sorb = 146.3 K, Cryostat outer surface = 22.9 C |
| 1505 | Let another 100 mbar N2 gas into cryostat vacuum jacket. (Fill hose with N2, then open green valve on pump manifold, leaving cryostat vacuum jacket valve open. 13 tube-lengths = 100 mbar @ manifold.) Cryostat vacuum jacket pressure = 8.6 mbar. |
| 1515 | MC(Cernox) = 83.5 K, Sorb = 149.0 K, Cryostat outer surface = 22.5 C |
| 1515 | Pump mixture out of fridge and cold LN2 Trap 2 to dump. |
| 1520 | MC(Cernox) = 84.6 K, Sorb = 151.6 K, Cryostat outer surface = 22.0 C |
| 1530 | MC(Cernox) = 86.4 K, Sorb = 157.4 K, Cryostat outer surface = 21.4 C |
| 1615 | MC(Cernox) = 95.1 K, Sorb = 185.4 K, Cryostat outer surface = 20.0 C |
| 1640 | MC(Cernox) = 100.6 K, Sorb = 199.6 K, Cryostat outer surface = 19.8 C |
| | Warming time constant is around 15 hours. Should reach 273 K around midnight tomorrow night. |
| 1700 | MC(Cernox) = 105.1 K, Sorb = 210.8 K, Cryostat outer surface = 19.7 C |
| 1845 | MC(Cernox) = 126.8 K |
| 2145 | MC(Cernox) = 157.7 K |