2019/07/19 (Friday)
| Setup | DIB1/3/4 → 3.2 MHz filters 2/3/1 → cable 3/1/2 → gender changer ?/3/2 → HVConn 1/3/2 → HV 1/2 → DCRCX(4)/DCRC55(1) DCRC33(2) → 1kV power supply → HV input Three walls of the lead/poly shield are up. |
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| Status: Recovered yesterday after a fridge failure. Taking data overnight, base temp around 39 mK. |
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| 0932 | Tower/MC/Coldplate = 38.9/30.2/199 mK, Still = 1.3 K / 0.10 mbar / 0 mW, G1/G2 = 101/109 mbar, 1K Pot = 1.72 K / 85 mbar. MB = 26.9% |
| 0942 | Fill LN2 cold trap bath. |
| 1320 | Begin LHe transfer. MB = 19.9% |
| 1350 | At the start of the transfer, 1K pot pressure runs off scale, comes back down after a minute, then wanders around 100-300 mbar during transfer. |
| 1355 | Cease LHe transfer. MB=91.7% |
| 1400 | 1K pot stabilizing around 80 mbar. |
| 1415 | The new anode for the Pfeiffer vacuum gauge finally arrived. Reassemble gauge, and attach to turbo pump station as usual. Seems to be working. |
| 1420 | Pumping out manifold with turbo pump up to IVC valves. Turbo = 40 nbar. |
| 1425 | Pumping out manifold with turbo pump up to IVC valves. Turbo = 15 nbar. |
| 1550 | Fill LN2 cold trap bath. |
| 1630 | Pumping out manifold with turbo pump up to IVC valves. Turbo = 4.6 nbar. Open IVC valves to start pumping on it again. Pressure falls a little, to 3.4 nbar. |
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| 1600 | Start a sequence of 8 @ 50 min series at HV = 180→306V, rate 2.49V/min, with 10% prebias for 2 minutes, flash at end with 30 min wait. CDMS detector: Driver Gains = 1x, DCRC4/1 QET biases = (490/400/495)/(420/480/450) uA, Front-End Gains = (2/2/3)/(5/5/5) 1000 BOR, 5Hz InRun randoms, trigger on DCRC1pD threshold = 6, baseline/sample length = 120/28 (standard 16/5), phonon pre-pulse 500 (standard is 500). Use sequence HVdrift_8X180V_2p49VPM_loopversion_prebias_10_2_dur_50min_flashDCRC_1_4.msl |
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| 1655 | HV leakage is much higher now according to Vtest…. let's investigate…. |
| The purge hose is still connected to the LN2 Dewar and the bag on the ebox. And gas is still flowing from the Dewar at the usual low rate. And yet leakage is around twice what it was for all the series from yesterday and this morning. Vtest = 17 mV with Vbias = 300 V. Previously Vtest was maxing out at 9 mV. It's a pretty hot day today, maybe humidity in the lab is unusually high? | |
| 1700 | Open LN2 Dewar vent valve a little bit more to increase flow to Ebox purge. |
| 1900 | Leakage is getting even worse. It is, indeed, extremely hot and humid out - your glasses fog up when you step outside from an air-conditioned building. |
| After the first few series the leakage settled, to a little over 10 mV at the max, a bit higher than before today. |