2012/06/02
| 1040 | Mixing chamber: 77.5 K; Begin pumping out exchange gas. |
|---|---|
| 1047 | Filled LN2 cold trap. |
| 1525 | Conduct electrical check at 77 K. No problems witnessed. |
| Start evacuating helium transfer stick jacket with dry pump. | |
| Warm up leak checker. Twenty-five minutes after being turned on, leak checker records correct value for internal leak rate, therefore no need for recalibration. | |
| Mixing chamber temperature is 77.5 K, and has been for the last few hours. One would expect the temperature to rise as exchange gas has been pumped out. Is this an indication of a leak? We'll know soon… | |
| 1635 | Pump mixture into dump in preparation for throughput test. |
| 1640 | Helium background leak rate 3.4E-9 mbar l/s. Start blowing out nitrogen. |
| 1730 | Finished blowing nitrogen out of main bath. Helium leak rate 3.7E-9 mbar l/s: barely any change, so no indication of a leak. |
| 1750 | Pressure in main bath 0.14 mbar: all nitrogen has been blown out. |
| 1800 | Conduct throughput test: 31 mbar/min. Good enough. Background helium leak rate 5.9E-9 mbar l/s: no change, so no leak. Pump mixture into dump. |
| 1821 | Pumped and flushed main bath. Evacuated 1 K pot. Filled IVC with 0.1 mbar of He gas. |
| 1835 | Start helium transfer. |
| 1955 | Pump out helium exchange gas at mixing chamber temperature of 8 K. |
| 2025 | End LHe transfer (85.8%) |
| 2100 | Conduct electrical check. Everything looks good. |
| Detector: | 51 pF Capacitor | BH: | Stripline: | 19 | |||||||
| SC: | Flexible v4 | 300 K | LN | LHe | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Face: | 2 | Date | 2012-05-31 | Date | 2012-06-02 | Date | 2012-06-02 | ||||
| SQUET: | ZC23 | Who | HC & RR | Who | HC | Who | HC & RR | ||||
| Signal | Pos. lead | Gnd lead | Nominal | Actual | Chassis | Nominal | Actual | Chassis | Nominal | Actual | Chassis |
| (Gnd lead) | (Gnd lead) | (Gnd lead) | |||||||||
| Nominal: | Nominal: | Nominal: | |||||||||
| < 0.1 nS | < 0.1 nS | < 0.1 nS | |||||||||
| Charge | |||||||||||
| FET heater +/- | 45 | 46 | 1.0 - 1.1 k | 1.068 | OK | 1.0 - 1.1 k | 1.044 | OK | 1.0 - 1.1 k | 1.25 | OK |
| Qi bias/QET Ret | 15 | 24 - 26 nS | <0.1 | OK | < 1 nS | <0.1 | OK | <1 nS | <0.1 | OK | |
| Qo bias/QET Ret | 11 | <0.2 | OK | <0.1 | OK | <1 nS | <0.1 | OK | |||
| Qi feedback/Drain/Source | 50 | 16, 31 | 15 - 17 nS | 12 | OK | 6 - 8 nS | 10 | OK | <1 nS | 9 | OK |
| Qo feedback/Drain/Source | 30 | 12, 27 | 11 | OK | 10 | OK | <1 nS | 9 | OK | ||
| Detector: | 51 pF Capacitor | BH: | Stripline: | 20 | |||||||
| SC: | ZB1-1-9 | 300 K | LN | LHe | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Face: | 5 | Date | 2012-05-31 | Date | 2012-06-02 | Date | 2012-06-02 | ||||
| SQUET: | ZC70 | Who | HC & RR | Who | HC | Who | HC & RR | ||||
| Signal | Pos. lead | Gnd lead | Nominal | Actual | Chassis | Nominal | Actual | Chassis | Nominal | Actual | Chassis |
| (Gnd lead) | (Gnd lead) | (Gnd lead) | |||||||||
| Nominal: | Nominal: | Nominal: | |||||||||
| < 0.1 nS | < 0.1 nS | < 0.1 nS | |||||||||
| Charge | |||||||||||
| FET heater +/- | 45 | 46 | 1.0 - 1.1 k | 1.06 | OK | 1.0 - 1.1 k | 1.04 | OK | 1.0 - 1.1 k | 1.16 | OK |
| Qi bias/QET Ret | 15 | 24 - 26 nS | <0.1 | OK | < 1 nS | <0.1 | OK | <1 nS | <0.1 | OK | |
| Qo bias/QET Ret | 11 | <0.1 | OK | <0.1 | OK | <1 nS | <0.1 | OK | |||
| Qi feedback/Drain/Source | 50 | 16, 31 | 15 - 17 nS | 23 | OK | 6 - 8 nS | 20 | OK | <1 nS | 18 | OK |
| Qo feedback/Drain/Source | 30 | 12, 27 | 23 | OK | 20 | OK | <1 nS | 19 | OK | ||
| 2200 | Puzzled as to why temperature was rising even though IVC pressure was 4.6E-3 mbar. Firstly, IVC pressure shouldn't be that high. Secondly, if there is still exchange gas in the IVC, temperature should be lower. Discovered that mixing chamber heater was still on, full blast at 20 mW! Shut off heater, and temperature started to fall. IVC pressure is a bit of a mystery. Deal with it tomorrow. |
|---|---|
| Fill N2 cold trap full. |