2020/07/24 (Friday)
- Lab in-person: Matt
- Virtual partner: Michael
| 0915 | Matt Fritts body temperature = 97.5 F |
|---|---|
| Setup | Run 73. DIB 1/3/4 → Stripline 43/48/41 → Cable 3/1/2 → nothing/nothing/accessory_interposer → HV_Conn 1/3/2 → HV 1/2 → DCRCX(4)/DCRC50(3)-master; DCRC33(2) → HV control. DCRCs on overnight. Lead/poly shield erected (4 lead walls, 2 poly walls). |
| 0855 | MB = 64.2% |
| 0920 | Tower/MC/Coldplate = 54.6/29.5/183 mK, Still = 1.39 K / 0.15 mbar / 5 mW, G1/G2= 280/257 mbar, 1K Pot = 1.66 K / 30±2 mbar. |
| Overnight the tower cooled to a minimum of 54.8 mK at 2:00 am, then warmed a little to 55.0 mK, then at 8:00 am started cooling again steadily. | |
| 1100 | Fill LN2 cold trap bath using the new long copper tube, no rubber hose (we have a new one but I'll just use the copper for now, if it works). |
| 1140 | Matt leaves lab |
| 1235 | Matt Fritts body temperature = 98.4 F |
| 1430 | Finish quick manual IbIs on all working channels. Choose the following transition points: QET Bias DCRC4/DCRC3 = 0,240,320,0/0,300,340,380 |
| These biases are chosen as reasonably in the middle of the transition somewhere. But pulses aren't very pretty. There seems to be thermoelectric oscillations in all channels. | |
| Here's an alternative set toward the high end of the transitions: QET Bias DCRC4/DCRC3 = 0,280,340,0/0,340,380,420 |
|
| It's not obvious that these higher biases give better results. Definitely can see that at the lower bias, pF has higher amplitude pulses (checked this by doing a 100 running average on the pulse viewer). Also requires higher threshold, so lower bias makes stronger pulses and stronger noise. Hard to tell whether S/N is better one way or the other. We'll stick to the lower biases, because this will give more reliable dP/dI calculations from IbIs. | |
| 1545 | Tower = 55.5 mK |
| 1546 | Start a 60 min series at HV = 0, CDMS detector: Driver Gains = 1x, DCRC4/3 QET biases = (0,240,320,0)/(0,300,340,380) uA, Front-End Gains = (3/3/3)/(5/5/5) 1000 BOR randoms, trigger on DCRC1pD threshold = 40 Use sequence SimpleDataLoopNoFlash.msl |
| 1625 | Create a sequence to take data at 5V, drifted, using the python code to generate it: |
from directory:
pysequencer
command:
python HVscan.py -iDCRC 2 -HVs 5 -HVcalFile HV_calibrations/HV_DCRC2_control_cals_500V_200721.txt -HVdriftRate 0.031 -HVpreBias 10/2 -tSeries 60 -DCRCs2Flash 3 >> ../../sequencer/HVdrift_5V_31mVps_pre10-2_60min.msl
ANALYSIS OF TODAY'S DATASET (here's the Root code):
- After processing today's data, I tried a quick calibration and a noise measurement
- Noise sigma (PTOF) = 6.3 keV
- This is 20X worse than Run72!
- probably shouldn't be too surprised given how nasty our pulses look
- Gain is a little lower than in Run72, about 36% lower
- The Run 72 0-Volt data from 2020 Mar 24 was taken at a very similar Tower temperature
- but at significantly higher QET biases
- biases that according to our IbIs are near the top, or over the top of the transition
- and we do see much better pulse shapes in this run at those much higher QET biases (in some channels at least)