2017/09/23 (Saturday)
| Status: Cooled to base yesterday. Tower stable overnight. | |
| 1052 | Tower/MC/Coldplate = 65.1/49/308 mK, Still = 1.07 K / 0.130 mbar, G1/G2 = 89/93 mbar, 1K Pot = 1.68 K / 60 mbar. MB = 31.9% |
| 1056 | Fill LN2 cold trap full. |
| 1155 | Modify DIB1 switchboard to include contact free bias resistors. |
| 1158 | Start up Midas DAQ |
| 1200 | Enable only DCRC1. Set all DCRC1 SQUID and QET biases to 0, all phonon gains to 1. DCRC1 charge bias and AmpOffsets = 0. |
| 1205 | Plug in DCRC1→ DIB1 switchboard → DIB1 cable. Power on DCRC1. ~2mK temp spike, returns to base. |
| 1208 | Start dcrcDriver, towerfe, and triggerfe. |
| 1218 | Set up VNC session as fritts. Change vncpassword to standard CDMS password. |
| 1219 | Tower temp has been slowly climbing, now at 67.9 mK |
| 1221 | Start pulse viewer. Can see DCRC1 charge traces, but no pulses. Both channels are offset at around 3V. Not sure why its triggering though, randoms are off and no threshold triggers set. Also not set to trigger on test signal. |
| 1224 | Hmm, randoms trigger was set in popup SQUID Control window in SQUIDTuningGui. |
| 1226 | Can see small pulses when triggering on either charge channel (QA or QC). They appear exponential (little to no ringing) |
| 1234 | Tower has climbed to 70.7 mK with little humps along the way. |
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| 1235 | Stop DCRC programs and power down DCRC1. |
| 1326 | Temperature has settled back at 65mK, but it continued to have regular excursions on the way down. The first little bump shown below is when first plugging the DCRC in. The rest seemed uncorrelated with any actions of mine. |
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| 1334 | Plug DCRC1 into DIB3 with DIB3 switchboard and power on. Small temp rise, returns to base. |
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| 1343 | DIB3QO (QD) also has a baseline around 3V, but no pulses are observed. Furthermore, it takes a substantially higher trigger level (~5000 vs 35 on DIB1) to get out of the noise. Noise on DIB3QO(QD) is 0.03 Vpp. |
| 1346 | Temp has again climbed since turing on DCRC, starting programs. Now at 71.2 mK. Again the temperature oscillations shown above are present. |
| 1348 | Stop programs and power down DCRC1. |
| 1350 | Plug DCRC1 into DIB4 with DIB4 switchboard and power on, start up programs. |
| 1351 | DIB4QI(QB) noise = 0.07 Vpp, DIB4QO(QE) noise = 0.07 Vpp |
| 1355 | No pulses seen on either DIB4 channel. Trigger levels to reach edge of noise is comparable to that seen on DIB1. |
| 1359 | Power down programs, return DCRC1 to DIB1. DIB1QI(QA) noise = 0.03Vpp, DIB1QO(QC) noise = 0.02Vpp. Now there are no pulses seen on DIB1 and it takes trigger levels above 1000 to get to edge of noise… |
| 1407 | Plug DCRC2 into DIB3 with DIB3 switchboard. Power it on. Set DCRC2 phonon biases to 0 in ODB. Enable DCRC2, start programs. |
| 1413 | Programs keep crashing when I try to view pulses (start a run). I have DCRC1/2=master/slave. |
| 1418 |
<blockquote>Connection broken to “towerfe3_01” on host cdms2.spa.umn.edu, recv() errno 104 (Connection reset by peer)</blockquote>
| 1420 | Restart MIDAS, still no luck. |
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| 1423 | Cannot reach DCRC1 via telnet either. Power cycle DCRC1, now it can be seen on telnet. |
| 1425 | Start up programs with just DCRC1 enabled. Can see traces in pulse viewer. Now there are pulses again. DCRC1 must have gotten in a bad mood for a while there. |
| 1430 | Restart run with DCRC2 enabled and connected to DIB3. Run starts fine, but now pulses are gone from DIB1 and we're triggering completely in the noise. DCRC2 charge channels are railed. End run, stop programs. |
| 1431 | Tower temp has climbed to 81 mK |
| 1434 | Plug in timing link cable from DCRC1 to DCRC2. Restart run. Now there's low frequency noise on DCRC1. |
| 1436 | Okay, got it working with the following order. 1) Attach timing link. 2) Power on DCRCs 3) start programs 4) Start run/pulse viewer. Now I can see traces on both DCRCs 1 and 2. The triggering is still strange, but with randoms, I can see pulses occasionally each of the 3 connected channels. |
| 1454 | Try turning on IR LEDs on electrode using DIB3. See no temp response for positive or negative 0.6mA current. Switch to UV LEDs. UV LEDs do heat the fridge with -0.6mA. Later: I'm not sure what's going wrong with the electrode IR LEDs here. They looked fine in electrical checks. May be a switchboard wiring error. Will have to try DIB LEDs also. |
| 1500 | Tower temp looks to be flattening out at ~100mK with both UV LEDs at -0.6mA. Increasing this to -0.7 mA gets it to 120mK. |
| 1504 | Increase UV LED current to -0.8 mA and leave them running. The Flashing DCRC control tool has no current settings, so we'll have to flash manually until we modify it. |
| 1815 | Detector is baking Tower/MC/Coldplate = 179/76/148 mK, Still = 2.07 K / 0.140 mbar, G1/G2 = 109/112 mbar, 1K Pot = 1.68 K / 60 mbar. MB = 18.1% |
| 1830 | Fill LN2 cold trap full. |
| 1845 | Begin LHe transfer (MB = 17.7%) |
| 2000 | End LHe transfer (MB = 76.0%) - Something weird is going on with the level meter. Bath level was going up as expected until around 85% when the readout suddenly showed Err. By pressing rate button, level reading returned. Checked back after less than 5 minutes and same thing happened again, but then level read 98.5%. Immediately stopped the transfer. Level meter read Err and pressing the rate button had no effect. Pressed rate button again after a few minutes and the reading changed from Err to 99.1%, then to 76.0%. I'm not sure if I trust this reading, but since the transfer had lasted a little over an hour I assume the bath should be near full. Will check tomorrow to see if meter is still functional. |
| 2217 | Tower temp = 175 mK (temperature logging is enabled at vuk-01/i/K100/temperature_20170923.txt). Don't want to forget about the bake, so turn off DCRC2 LEDs for tonight. Temp begins falling. |
| 2226 | Tower temp = 120 mK |
| 2240 | Tower temp = 89 mK |