2022/11/25 (Friday)
- Lab in-personnel: Matt
| Status | Run 76 in progress |
|---|---|
| Setup | Cables 2/3/1 → diverter/nothing/nothing → Side2-readout HV CONN 1/3/2 → HV 1(L)/2(R) → DCRC50(3)/DCRC55(1), DCRC33(2)→HV control, NaI trigger signal → DCRCX(4) Lead/poly shield fully assembled. Boron-filled socks covering NaI detectors. PuBe behind lead wall on W side of fridge. NaI array trigger window = 4.73 - 5.13 MeV |
| Cooled to base two days ago after twenty-sixth 5K pumpout. Taking SiHV-triggered data overnight with a higher than usual trigger threshold, mainly just to monitor when the phonon channels go bad. | |
| At some point last night I could no longer remotely connect to the fridge computer, but it's working again today. | |
| 0545 | Dial HV down to 0V |
| 0547 | Start 0 V PuBe data series ## min long, with 1000 initial randoms, 5 Hz in-run randoms, trigger on DCRC1pA threshold 100. Start series with the Start Button |
| 1205 | At around this time dump sizes started getting smaller. This is 44 hours after cooling to base, so roughly consistent with hold times in recent cycles. |
| 1230 | DCRC1pA baseline = -0.783 V |
| 1235 | At this point dump sizes start falling steadily to around 5MB, consistent with no triggers |
| 1440 | DCRC1pA baseline = -0.734 V, no pulses |
| 1445 | Close V6 to stop circulation. |
| 1455 | V6 is now fully closed (light is presumably off on IGH, Still pressure is rising, Condenser pressure falling). Turn off 3He pump |
| 1640 | Close 1K Pot needle valve |
| 1643 | MB = 30.7% |
| 1645 | Fill LN2 cold trap bath, partially - LN2 storage Dewar needs a refill. |
| 1645 | Turn on Still and MC heaters to 20 mW each |
| 1645 | Open V3; mixture from Still side flows into Condenser side. |
| 1650 | Close 1K Pot speedivalve, V4a, 4He pump inlet valve. Turn off 4He pump. Close recovery valve to 4He pump outlet. NOTE: remember to open recovery valve when the pump is turned back on. |
| 1730 | MC/1KPot = 3.72/3.63 K |
| 1730 | Check pressure in IVC: 12 nbar |
| 1730 | Start pumping out IVC with turbo pump. |
| 1730 | Turn off DAQ programs and unplug DCRCs 1&3 |
| 1740 | MC/1KPot = 3.88/3.84 K. G1(fridge) = 760 mbar. |
| 1740 | Open V9 to release pressure into the dump. |
| 2010 | Tower = 10.00 K. Turn off MC and Still heaters |
Because the ZAP tool isn't working via the browser interface, here are some notes about what the zap sequence does. If necessary this could be done manually or via the RootSequencer.
- Set Charge Biases, SQUID bias, QET bias, Phonon Polarity all to 0
- set Playground/Run_sequence to “ZAP” (is this necessary?)
- set /DCRC#/LED/Enable_ZAP_Charging to “y”, wait 60 seconds
- set /DCRC#/Phonon/SQUIDSource[#] to “y”, wait 2 seconds
- set /DCRC#/Phonon/SQUIDSource[#] to “n”, wait 30 seconds
- set /DCRC#/Phonon/SQUIDSource[#] to “y”, wait 2 seconds (again)
- set /DCRC#/Phonon/SQUIDSource[#] to “n”, wait 30 seconds (again)
- set /DCRC#/LED/Enable_ZAP_Charging to “n”
- restore Charge Biases, SQUID bias, QET bias, Phonon Polarity to original values
| 6.33-8 K | 90 min |
| 7.22-3 K | 60 min |
| 8.17 K | 30 min |