2020/08/04 (Tuesday)
- Lab in-person: Matt
- Virtual partner: Zach
| Setup | Run 73. DIB 1/3/4 → Stripline 43/48/41 → pi-filters 1/2/3 → Cable 3/1/2 → nothing/nothing/accessory_interposer → HV_Conn 1/3/2 → HV 1/2 → DCRCX(4)/DCRC55(1)-master; DCRC33(2) → HV control. DCRCs on overnight. Lead/poly shield erected (4 lead walls, 2 poly walls). |
|---|---|
| 1005 | Matt Fritts body temperature = 96.7 F |
| 0545 | MB = 43.3% |
| 0630 | Start a 60 min series at HV = -0V, CDMS detector: Driver Gains = 1x, DCRC4/1 QET biases = (0,320,370,0)/(0,360,420,420) uA, Front-End Gains = (3/3/3)/(5/5/5) 1000 BOR randoms, trigger on DCRC1pD threshold = 8 Use sequence SimpleDataLoopNoFlash.msl |
| 0630 | Tower = 51.4 mK |
| 1210 | Write sequence for drifting from -15 V at rate 23.9 mV/s. This is the rate shown to work for -10V data. HVdrift_neg15V_23p9mVps_multiloop10_nopre_60min.msl |
| 1212 | Start a 60 min series at HV = -15V, drifting -0.0239 V/s, no prebias, CDMS detector: Driver Gains = 1x, DCRC4/1 QET biases = (0,320,370,0)/(0,360,420,420) uA, Front-End Gains = (3/3/3)/(5/5/5) 1000 BOR randoms, trigger on DCRC1pD threshold = 8 Use sequence HVdrift_neg15V_23p9mVps_multiloop10_nopre_60min.msl |
| 1215 | Tower = 51.4 mK |
| 1215 | Vtest = -0.7 mV, shortly after beginning of drift |
| 1322 | Vtest = -3.2 mV, HV = -100.0 V, drift ends. Overall Lag ratio = 70/60 = 1.17. This is not too far from the intended 1.10. |
| Looks like it was fastest at the beginning of the series, then got laggier later. | |
| Rate was around -21.0 mV/s at first, fell to around -19 mV/s at end. Lag ratio 1.13→1.26. |
| 1330 | Matt enters lab |
|---|---|
| 1347 | Begin LHe transfer @ MB = 29.7% |
| 1419 | Ended LHe transfer @ MB = 92.3% |
| 1435 | Filled LN2 cold trap bath. |
| 1510 | Tower/MC/Coldplate = 57.5/38.5/193 mK, Still = 1.50 K / 0.18 mbar / 5 mW, G1/G2= 473/431 mbar, 1K Pot = 1.63 K / 26±2 mbar. |
| NOTE: temperature is still elevated after the LHe transfer | |
| 1525 | Swap HV leads to positive polarity. |
| 1335 | Matt leaves lab |
| 1630 | Matt Fritts body temperature = 97.4 F |
| Right around 15:30, the HV reading suddenly jumped from its normal 30 mV to about 2 V, then wavered between 1V and 2V for about 15 minutes, then fell. Then it wavered in weird patterns between 0 and 0.3 V for about 30 minutes. By 16:20 it had mostly settled. While it was elevated, Vtest was reacting as well. | |
| 2300 | HV is still unstable, dunno what the hell is wrong. At the moment it is around 2V. |
| 2310 | Stepping the DCRC2 /Charge/Bias up from 11.56 (which previously corresponded to 0V) to 11.60 has brought the HV bias down to around 70 mV. Maybe the calibration has shifted. |
| 2315 | Write sequence for 15V drifted using rate appropriate for positive bias. Also using the 11.60 value above for 0V but otherwise using the same calibration. HVdrift_pos15V_22p3mVps_multiloop10_nopre_60min.msl |
| 2322 | Start a 60 min series at HV = 15V, drifting 0.0223 V/s, no prebias, CDMS detector: Driver Gains = 1x, DCRC4/1 QET biases = (0,320,370,0)/(0,360,420,420) uA, Front-End Gains = (3/3/3)/(5/5/5) 1000 BOR randoms, trigger on DCRC1pD threshold = 8 Use sequence HVdrift_pos15V_22p3mVps_multiloop10_nopre_60min.msl |
| 2325 | Tower = 53.2 mK |
| 2325 | Vtest = 0.6 mV, shortly after beginning of drift. Drift seems to start around 17V instead of 15V, suggesting the calibration has shifted. |
| HV took a 2V downward excursion briefly. Seems unstable. | |
| 0040 | Vtest = 2.7 mV, HV = 95.2 V, drift ends. Overall Lag Ratio = 78/60 = 1.30, high. |
| Looking more closely, HV was relatively unstable for first 20 minutes, then rose at steady 17.3 mV/s. This later period is a lag ratio of 1.29 - so DAQ was laggy, 3X worse than the “good” state. |
Single person helium transfer steps
| Obtain the transfer sticks and attach the extensions & o-rings to each end. | |
| Place the dewar side transfer stick on the hooks. | |
| Wipe water from top of fridge with a rag. | |
| Weight and bring in the dewar. | |
| Delete the previous camera images, start the camera for helium recovery. | |
| Fill out the transfer log. | |
| Insert the fridge side transfer stick into the fridge (middle tube). Keep the cover off at first then rescrew. Watch the helium recovery meter as this is done. | |
| Climb down and insert the dewar side transfer stick partially into the dewar, keeping the other end on it's hook. | |
| Climb the ladder, insert the dewar side transfer stick further and wait for the plume. | |
| Once the plume starts, unscrew the cover on the fridge side transfer stick and connect the two transfer sticks. | |
| Bring the dewar side transfer stick's extension down and hook up the dewar to power/gas cylinder. | |
| Stop pressurizing the dewar at MB~90% then wait for MB~95%. | |
| Bring the dewar side transfer stick & extension up. | |
| Climb the ladder, disconnect the two transfer sticks, rescrew the cover on the fridge side transfer stick. | |
| Place the end of the dewar side transfer stick on it's hook. | |
| Climb down and relieve some pressure from the dewar then completely remove the dewar side transfer stick, putting it on the hooks. | |
| Completely remove the fridge side transfer stick and cover the fridge tube with the rubber stopper. | |
| Weight and return the dewar and place the helium order. | |
| Stop the helium recovery camera, find the initial recovery level and the recovery level 10min after the transfer. | |
| Fill out the transfer log. Return the transfer stick. |