2020/09/09 (Wednesday)
- Lab in-person: Zach
- Virtual partner: Matt
| 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). |
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| 0750 | MB = 33.3% |
| 0810 | Tower = 48.1 mK. Chilly! |
| 0815 | Working on a way to run data sequences remotely from the sequencer. Using odbedit on cdms2 you can control MIDAS from a Linux command line. I (Matt) am writing Root macros to do exactly what our drifted-bias sequences do, by sending commands to the system and sleeping for the appropriate time intervals. Nick had started to play with doing this with Python but I'm fluent in Root so I'm doing it that way. |
| The new Root Sequencer is expected to have no lag. So drift rates should be adjusted under this assumption. On Aug 31 we ran at 300V with nominal drift rate 31.6 mV/s and lag ratio 1.18, and the drift looked just right. So the true drift rate was 26.8 mV/s. | |
| 0830 | Check phonon channels with pulse viewer. One was railed, adjusted its offset. Others look good. |
| 0847 | Start a 60 min series at HV = +300V, drifting 0.0268 V/s, prebias 15% for 2min, CDMS detector: Driver Gains = 1x, DCRC4/1 QET biases = (0,320,370,0)/(0,360,420,410)uA, Front-End Gains = (3/3/3)/(5/5/5) 1000 BOR & 5 Hz in-run randoms, trigger on DCRC1pD threshold = 8 Use Root sequencer, function drift_p300 |
| 0847 | Tower = 48.1 mK |
| 0847 | Vtest = 5.0 mV shortly after drift begins. Drift appears to start at +301.5 V. 0.66% HV loss. |
| 0901 | Second drift loop begins. The first loop should have taken 860 seconds = 14.3 minutes. Looks like there's no noticeable lag. |
| 0947 | Series ends, Lag Ratio ~1.0 (no apparent lag). Vtest = 5.4 mV. HV at end of drift should be 399.6 V according to sequence, indicating 0.54% HV loss (small!) |
| 0947 | Tower = 48.0 mK |
| Root Sequencer worked beautifully! | |
| later look at data shows Lag Ratio = 0.994 |
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| 60 keV line looks like it falls a little, but I took a closer look at the 14keV line Dividing into 3 20min periods, 14keV line actually rises a little from 1st to 2nd third, then stays about the same from 2nd to 3rd third. Overall suggests that drift rate should maybe be reduced from 28.6 to 28.2 mV/s. |
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| y-delay and y-partition show shifts after the move in both the 60keV line and the lower lines. | |
| 1030 | Zach body temp = 98.5 |
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| 1045 | Zach arrives at lab. |
| 1050 | Tower/MC/Coldplate = 48.7/30.0/195 mK, Still = 1.50 K / 0.095 mbar / 0 mW, G1/G2= 248/284 mbar, 1K Pot = 1.70 K / 55±5 mbar. |
| 1050 | MB = 28.3% |
| 1108 | Filled LN2 cold trap bath. |
| 1115 | Disconnected LN2 dewar and sent to be filled. |
| 1134 | Begin LHe transfer @ MB = 28.3% |
| 1207 | Ended LHe transfer @ MB = 91.4% |
| 1255 | Returned LN2 dewar, purge is set up again. |
| 1301 | MB = 90.4% |
| 1303 | Zach leaves lab. |
| 1500 | Zach body temp = 99.0 |
| 1415 | I've extended the RootSequencer code to run a generic drifted sequence. The user can enter the HV and drift values. By default it runs a 60 minute series with 15%-2minute prebiasing, although those defaults can be changed by the user. The Root macro and instructions have been copied to /home/hep/cdmssoft/scdmsDAQ/MidasDAQ/online/scripts/rootsequencer |
| 1433 | Start a 60 min series at HV = +100V, drifting 0.0274 V/s, prebias 15% for 2min, CDMS detector: Driver Gains = 1x, DCRC4/1 QET biases = (0,320,370,0)/(0,360,420,410)uA, Front-End Gains = (3/3/3)/(5/5/5) 1000 BOR & 5 Hz in-run randoms, trigger on DCRC1pD threshold = 8 Use RootSequencer.c, function drift_sequence(100,0.0274) |
| 1433 | Tower = 49.2 mK |
| 1433 | Vtest = 1.6 mV shortly after drift begins. Drift appears to start at +106.2 V. 0.60% HV loss. |
| 1447 | Sharp jump in otherwise steady drift, from 128.2 to 131.4 V. This suggests a glitch in the Root code. |
| 1508 | Another smaller glitch: HV fell from 165.9 to 163.5 then back after ~10 seconds |
| 1517 | Another glitch: HV fell from 180.1 to 178.9 in ~10 seconds, did not recover |
| 1533 | Not sure what happened here - HV jumped from 200.5 V to off-scale it seems… a few minutes later it fell into scale and ramped down. |
| 1533 | Series ends I think, no apparent lag. Vtest = 2.4 mV. HV at end of drift looks like 200.5 V, indicating 0.48% HV loss |
| 1533 | Tower = 49.3 mK |
| 1540 | Severe glitch during rampdown: after reaching 0V it suddenly jumped to 200V, then started ramping down again… Second rampdown OK, ends with flash. |
| 1555 | Found the rampdown glitch - I inadvertently left in rampdown lines from an earlier, non-settable version (dumb). But I don't know the source of the apparent glitches that occurred during the drift. |
| later look at data shows Lag Ratio = 0.992 |
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| You can see the first glitch at around 14 minutes Apart from that glitch the drift rate seems about right |