2016/09/29 (Thursday)

Previous Day

	DCRC1 and DCRC3 powered on and connected through HV setup EBoxDIB 2/3 → 3.2 MHz filters → Cables → remapping board I/remapping board II → HVside2board “DIB1”/“DIB2” → DCRC55(1)/50(3). Remapping boards have all possible lines switched off. .
	Baking using the UV LEDs for 12 hours last night. Tower temp held at 400 mK until 08:38, then fell to base in about 40 minutes
0920	Tower/MC/Coldplate = 82/56/??(3.1 kΩ) mK, Still = 1.12 K / 95 μbar, G1/G2 = 210/180 mbar, 1K Pot = 1.57 K / 6.0 mbar. MB = 73.9% 1K Pot has been stable. Boiloff rate is good. Yesterday pressure was released at 52 minutes after 91.2% fill. It was released a few times later than that as well.
0925	Fill LN2 cold trap bath.
0949	With 33kΩ resistor on DIB1 QOFB line, manually start series of 20 minutes data with 60V HV/ -10V DIB1 with 1000 starting/1000 ending randoms with 1000 ADC Bin trigger threshold with ChargeTriggerBaselineLength=300, ChargeTriggerSampleLength=10 on DIB1 Qo. No Co-57 source present.
1051	Cease data taking. UV flash for 30 seconds, 10 minute cooldown.
1020	Move the 1 Ci PuBe source into the lab. It is in its paraffin-filled transport barrel on a stool behind the fridge on the west wall (by the LN2 cold traps). One of the movable shield walls has been moved into the west position between the PuBe source and the fridge.
1052	Switch DCRCs 55 and 50 Setup: EBoxDIB 2/3 → 3.2 MHz filters → Cables → remapping board I/remapping board II → HVside2board “DIB1”/“DIB2” → DCRC50(3)/55(1). Remapping boards have all possible lines switched off.
1129	Tests on DCRC50 triggering showed that this board triggers on Qo noise with Vpp around 0.09, even when trigger threshold is set as high as 30000 ADC Bin (~3V). Furthermore, it triggers on Qi when the threshold is set around 1000 ADC Bin, even though Qi is flatlined. Telnet indicates that the correct thresholds are being sent to the board. It is also odd that trigger thresholds at low 1 ADC Bin was not sufficient to trigger on the PA and PB noise produced by reading out LEDs. Power cycle both boards to check this again.
1143	Cease trigger testing after finding a good threshold at 3333 ADC Bin. Seems off since that corresponds to 400 mV, yet we are still trigger on 100 Vpp pulses/noise and lower. UV flash for 30 seconds, 10 minute cooldown.
1157	Bring out Co-57 source and put in castle, source is 15“ from cryostat. Cryostat has 20.5” diameter so source is about 25“ from detector center.
1200	With 33kΩ resistor on DIB1 QOFB line, manually start series of 48 minutes data with 60V HV/ -10V DIB1 with 1000 starting/1000 ending / 1 hz randoms with 3333 ADC Bin trigger threshold with on DIB1 Qo. Co-57 source 15” from cryostat. Cryostat has 20.5“ diameter so source is about 25” from detector center.
1248	Cease data taking. Use SQUIDGUI to ensure that we are still triggering OK, and it seems fine. UV flash for 30 seconds, 10 minute cooldown.
1325	With 33kΩ resistor on DIB1 QOFB line, manually start series of 40 minutes data with 80V HV/ -10V DIB1 with 1000 starting/1000 ending / 1 hz randoms with 3333 ADC Bin trigger threshold with on DIB1 Qo. No Co-57 source present. Leakage current at 17 mV.
1409	Cease data taking. Looking at traces in BatViewer and SQUID GUI, we are now triggering on noise with Vpp~0.1V.
1426	UV flash for 30 seconds, 10 minute cooldown.
1427	We still seem to be having triggering issues. Although the noise level is the same as in past good runs(~0.1Vpp) we are unable to find a trigger level which is not dominated either by noise or by good-sized pulses. Either our signal from the detector has just fallen off, or something has changed in the DCRCs.
1425	Change DIB1 (now DCRC50) gender changer.
1525	Using DCRC50 as DIB2 and DCRC33 as DIB1 appeared to show some noise improvement, but triggering was an issue. Setting a trigger threshold on DCRC33 of 1 ADC Bin gave the same results as a threshold of 150 ADC: both showed very slow trigger rates and triggered on noise and pulses alike. However, we are now hopeful that switching so that DCRC50 is on DIB1 and DCRC33 is on DIB2 will help.
1555	Still having issues with triggering and noise. Commence 10 minute UV LED bake.
1620	Possibly resolve noise issue by changing ChargeTriggerSampleRate from its original value of 5 to 4. Switch back to DIB1=DCRC50 DIB2=DCRC55 and UV flash for 30 sec with 10 minute cooldown.
1637	Take out Co-57 source from safe. Place in castle 2m away from detector.
1640	With 33kΩ resistor on DIB1 QOFB line, manually start series of 20 minutes data with 20V HV/ -10V DIB1 with 1000 starting/1000 ending randoms with 220 ADC Bin trigger threshold with on DIB1 Qo. Co-57 2m from tower.

Allison's Final Thoughts:	We had a lot of issues with data taking today that might not be accurately portrayed in the run diary. To summarize the issues, our previous Qo trigger threshold, 150 ADC Bin, produced data overwhelmed with noise. Using the SQUIDGUI, we found that ~3400 ADC Bin was a minimum threshold to trigger on only pulses (in the GUI), but we still found our taken data filled with noise. The noise we were seeing had a Vpp of ~.1V that generally didn't change throughout our tests, even though the minimum trigger threshold constantly needed adjusting. We were uncertain if this noise was oscillating and/or from a new source, or if there was something going on with the trigger threshold/squid GUI. Using telnet we were able to prove that the trigger threshold we set in the ODB was the trigger threshold set on the DCRC board, so that was not the issue. We tried the following combinations of DCRC boards (DIB1/DIB2): DCRC50/DCRC55, DCRC55/DCRC50, DCRC33/DCRC50, DCRC50/DCRC33, and none fixed the issue. Although the Vpp of the noise was smaller when DCRC33 was the readout board (~0.08 Vpp), it would still trigger on noise even when the trigger threshold was >1000. While in the DCRC50/DCRC33 setup, we yet again tried UV flashing and 10 minute baking, as well as adjusting the wires on the switch boards. Again, nothing worked. Although we had fiddled with these values earlier and saw little improvement, we decided to alter the ChargeTriggerSampleRate from its original value of 5. Changing the value to 1,2, or 3 did not improve the situation, but changing the value to 4 caused the GUI to stop triggering on noise. We were able to reduce the trigger threshold to 150 ADC Bin without overwhelming our pulses with noise triggers. We switched back to our original setup with DIB1=DCRC50 DIB2=DCRC55, and after a flash we found that a trigger threshold of 220 ADC was sufficient to trigger predominately on pulses.

Allison's Final Thoughts:

We had a lot of issues with data taking today that might not be accurately portrayed in the run diary. To summarize the issues, our previous Qo trigger threshold, 150 ADC Bin, produced data overwhelmed with noise. Using the SQUIDGUI, we found that ~3400 ADC Bin was a minimum threshold to trigger on only pulses (in the GUI), but we still found our taken data filled with noise. The noise we were seeing had a Vpp of ~.1V that generally didn't change throughout our tests, even though the minimum trigger threshold constantly needed adjusting. We were uncertain if this noise was oscillating and/or from a new source, or if there was something going on with the trigger threshold/squid GUI. Using telnet we were able to prove that the trigger threshold we set in the ODB was the trigger threshold set on the DCRC board, so that was not the issue. We tried the following combinations of DCRC boards (DIB1/DIB2): DCRC50/DCRC55, DCRC55/DCRC50, DCRC33/DCRC50, DCRC50/DCRC33, and none fixed the issue. Although the Vpp of the noise was smaller when DCRC33 was the readout board (~0.08 Vpp), it would still trigger on noise even when the trigger threshold was >1000. While in the DCRC50/DCRC33 setup, we yet again tried UV flashing and 10 minute baking, as well as adjusting the wires on the switch boards. Again, nothing worked. Although we had fiddled with these values earlier and saw little improvement, we decided to alter the ChargeTriggerSampleRate from its original value of 5. Changing the value to 1,2, or 3 did not improve the situation, but changing the value to 4 caused the GUI to stop triggering on noise. We were able to reduce the trigger threshold to 150 ADC Bin without overwhelming our pulses with noise triggers. We switched back to our original setup with DIB1=DCRC50 DIB2=DCRC55, and after a flash we found that a trigger threshold of 220 ADC was sufficient to trigger predominately on pulses.

1703	Cease data taking. UV flash for 30 seconds, 10 minute cooldown.
1717	With 33kΩ resistor on DIB1 QOFB line, manually start series of 20 minutes data with 40V HV/ -10V DIB1 with 1000 starting/1000 ending randoms with 220 ADC Bin trigger threshold with on DIB1 Qo. Co-57 2m from tower. For the first 10 minutes, have a lead brick blocking the opening from the source castle to the fridge.
1750	Cease data taking. UV flash for 30 seconds, 10 minute cooldown.
1804	With 33kΩ resistor on DIB1 QOFB line, manually start series of 60 minutes data with -20V HV/ 10V DIB1 with 1000 starting/1000 ending randoms with 220 ADC Bin trigger threshold with on DIB1 Qo. Co-57 2m from tower.
1910	Cease data taking. UV flash for 30 seconds, 10 minute cooldown.
1912	Fill LN2 cold trap full.
1921	With 33kΩ resistor on DIB1 QOFB line, manually start series of 30 minutes data with -40V HV/ 10V DIB1 with 1000 starting/1000 ending randoms with 220 ADC Bin trigger threshold with on DIB1 Qo. Co-57 2m from tower. (5mV leakage current)
1953	Cease data taking. Put Co-57 source in safe in its lead container. Turn off the Geiger counter and remove sign from castle. Ground detector. Commence two hour UV bake and one hour cooldown before doing Alternating _flashandsweep_evenV.msl sequence (15 minute series of alternating +/- voltage from 12 to 0, only even values. 30 sec UV flash/10 minute cooldown in between.)
2253	Start automatic data taking sequence Alternating_flashandsweep_evenV.msl to take 15 minute series of alternating +/- DIB1 voltage from 12, -12, 10, -10 … down to 0, only even values (HV grounded). 30 sec UV flash/10 minute cooldown in between. 1000 starting/ending randoms and 220 ADC Bin trigger threshold.

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