2019/03/21 (Thursday)
| 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)/DCRC50(3) DCRC33(2) → 1kV power supply → HV input Lead poly shield is erected, N/E/W walls complete, no poly or lead on S wall. PuBe source present in paraffin barrel behind lead stack. |
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| 0850 | Tower/MC/Coldplate = 43.7/30.8/195 mK, Still = 1.75±0.15 K / 0.160 mbar, G1/G2 = 251/230 mbar, 1K Pot = 1.78 K / 16 mbar. MB = 74.0% |
| Tower temperature peaked by 1 or 2 mK several times last night. Again probably has something to do with the QETs. Currently it's down at its base level. | |
| 0855 | Fill LN2 cold trap bath |
| 1000 | Get all phonon transitions in transition and looking OK. |
| 1003 | Start PuBe series at HV = 300→400V @ 5.6 V/min (18 min duration) with 2 minute 15% prebias CDMS detector: Driver Gains = 1x, DCRC4/3 QET biases = (410/370/450)/(400/370/420) uA, Front-End Gains = (4/2/3)/(10/15/10) 1000 BOR randoms, trigger on DCRC3pB/D threshold = 7/7 use sequence HVdrift_300V_5p6VPM_prebias_15_2_dur_18min.msl |
| 1019 | HV = 305.6 V, Vtest = 45 mV. Data taking has started. All channels look OK. |
| 1038 | HV = 312.2 V, Vtest = 42 mV. MIDAS is stuck - the sequence seems to have stopped in the middle, MIDAS is unresponsive. |
| 1042 | Kill then restart MIDAS, restart DAQ programs. Sequence is starting where it left off. This will be a screwy data series. |
| 1045 | HV = 330.6 V, Vtest = 52 mV. All channels look OK. |
| 1115 | See temperature spike from flashing detector, 42.3→44.7 mK. |
| 1130 | DCRC3pB&C were railed, looked liked they were in s/c. Get them back into transition. |
| 1135 | Start PuBe series at HV = 300→400V @ 5.6 V/min (18 min duration) with 2 minute 15% prebias CDMS detector: Driver Gains = 1x, DCRC4/3 QET biases = (410/370/450)/(400/370/420) uA, Front-End Gains = (4/2/3)/(10/15/10) 1000 BOR randoms, trigger on DCRC3pB/D threshold = 7/7 use sequence HVdrift_300V_5p6VPM_prebias_15_2_dur_18min.msl |
| 1153 | HV = 315.0 V, Vtest = 48 mV. Data taking has started. All channels look OK. |
| 1204 | HV = 367.9 V, Vtest = 62 mV. All channels look OK. |
| 1212 | Ugh, MIDAS is stuck again. stupid. |
| 1214 | Restart MIDAS and DAQ programs. Sequence continues. |
| 1217 | Data taking finished, sequence is dialing down the HV. |
Calibration was pretty flat up to the last few minutes, after MIDAS locked up.
Noise width is ambiguous. A simple check based on PTOFamps0 calibrated to the 60 keV line yields 68 eV. An attempt at balancing (pC*2, pF*0.5, others the same) and summing, with a calibration to the 60 keV line, yields 40 eV. But in this calibration the 10 keV line seems to show up in the wrong place - if we recalibrate to the 10 keV line, we get 26 eV. It could be that 60 keV is rather saturated so that the 10-keV-based calibration is more correct at 0.
Also noticed that with a high-pF cut there is some indication of the lower Am lines but they are pretty weak. Should collect more statistics.
| 1220 | Tower = 42.3 mK |
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| 1335 | MB = 64.5% |
| 1555 | Tower = 42.8 mK |
| 1605 | All channels except DCRC3pC are still good. DCRC3pC looks like it fell into s/c, took a while to get it back. We'll try a somewhat higher QET bias (370→390 uA), maybe it will be more stable. If we want to take higher stats we need it to be stable between sequences. |
| 1635 | In the last few series the calibration lines are drifting up somewhat, so I'm trying to adjust the drift rate. Made a new sequence with 5.4 V/min instead of 5.6 V/min. |
| 1646 | Start PuBe series at HV = 300→400V @ 5.4 V/min (18 min duration) with 2 minute 15% prebias CDMS detector: Driver Gains = 1x, DCRC4/3 QET biases = (410/370/450)/(400/370/420) uA, Front-End Gains = (4/2/3)/(10/15/10) 1000 BOR randoms, trigger on DCRC3pB/D threshold = 7/7 use sequence HVdrift_300V_5p4VPM_prebias_15_2_dur_18min.msl |
| 1705 | Fill LN2 cold trap bath |
| 1705 | HV = 320.5 V, Vtest = 52 mV. Data in process. Check all the channels, all look good. |
| 1720 | Midas crashed again, HV = 392.4 V, Vtest = 63.0 mv. |
| 1725 | Kill MIDAS, then Restart MIDAS and DAQ programs. Sequence starts again. Looks like it was already at the ramp-down phase, data taking is stopped. |
Looks pretty flat.
| 1730 | All channels still look good. |
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| 1730 | Tower = 42.1 mK. MB = % |
| 1740 | Flash just finished, looks like all channels are still good. |
| 1750 | Spoke too soon, DCRC3pB just railed, but it seems to have happened after the temperature dropped agian, maybe the squid is having trouble staying locked with the temperature change? |
| 1600 | As with DCRC3pC earlier, looks like DCRC3pB fell into s/c, took a while to get it back. Trying a somewhat higher QET bias (400→420 uA), maybe it will be more stable. |
| HPGe Tests | |
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| 1415 | Set up HPGe detector with HVbias=2.00 kV with the same setup as on 3/6. Took 2000s background spectrum using EasyMCA in this manner. |
| 1500 | Ba source taken out. Placed in lead castle. |
| 1550 | Data taken with Ba source 8in from end of detector (z=16, r=0), 2000s live time. |
| 1600 | Ba source put away. |
| 1630 | Background data taken again, this time with the detector in the same position as it was when there was a source. |
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