2015/07/14 (Tuesday)
| Current configuration: DIB1/2/3 → 100MHz filter/none/none → DCRC55/33/50 | |
| 0853 | MC/Tower/Coldplate = 24.4/30.7/138 mK, Still = 0 mW / 0.11 mbar / 1.05 K, G1/G2 = 200/195 mbar, 1K Pot = 1.68 K / 13 mbar, Main bath = 22.5% |
| 0854 | G2 has been falling over the last few hours (198→195 mbar). Blockage forming in fridge? Nothing dramatic. |
| 0906 | Fill LN2 cold trap Dewar |
| 0943 | Power all three DCRCs, zap, set up phonons to previous settings |
| 0945 | looking at noise: |
| low frequency noise | |
|---|---|
| DIB1 | 1 kHz @ 8/0/6/8 mVpp, 250 Hz @ 0/5/0/0 mVpp |
| DIB2 | ~2 kHz in pC, 250 Hz @ 10/6/10/8 mVpp |
| DIB3 | ~2 kHz in all, 250 Hz @ 5/3/6/0 mVpp |
| 1020 | Bake detector about 4 minutes. |
|---|---|
| 1107 | Tower has cooled to 32 mK. |
| 1110 | Visual assessment of pulse quality (poor/mediocre/decent/good) and noise: |
| pulse quality | low frequency noise | |
|---|---|---|
| DIB1 | P/D/P/P | 1 kHz @ 0/0/0/6 mVpp, 250 Hz @ 4/8/5/6 mVpp |
| DIB2 | P/M/P/D | ~2 kHz in pA & pC, 250 Hz @ 4/6/3/11 mVpp |
| DIB3 | M/M/P/P | ~1 kHz sporadic, 250 Hz @ 4/7/6/0 mVpp |
| 1156 | Observations: grounding DIB1 phonons improves DIB2 pulses, particularly DIB2pA and pC. Grounding DIB3 phonons doesn't help DIB2 much. |
|---|---|
| 1204 | Change output gain and driver offsets of DIB3 pC&pD, pC/pD = 1/1 = -0.088/-0.046. Previously these output gains were 0 unlike the other six RevC.1 phonon channels. |
| 1209 | Set thresholds: |
| Current thresholds | ||||
|---|---|---|---|---|
| pA | pB | pC | pD | |
| DIB1 | 20 | 20 | 20 | 25 |
| DIB2 | 25 | 20 | 20 | 15 |
| DIB3 | 15 | 15 | 20 | 25 |
| 1220 | failed data run, MultiDAQ was set for 1 DIB, restart it. |
|---|---|
| 1231 | Apply -4/4 V but MultiDAQ reset them to 0/0 V, start bkg data |
| 1252 | Stop data, 0/0 V, flash 30 seconds. |
| 1310 | Tower is hot, 37 mK. 250 Hz noise is large, DIB2 pC/pD at 30/40 mVpp. After a few minutes fridge drops to 33.5 mK (still high) and pD noise falls to 20 mVpp. looks like a Bad State. |
| 1320 | Disconnect all boards. Temperature fluctuations continue for over 30 minutes. |
| 1405 | Commence LHe transfer (13.8%). |
| 1415 | Tower down to 30.5 mK, reconnect boards & zap. Reset phonons. |
| 1435 | End LHe transfer (81.4%, 11 L remaining, dewar 3107). |
| pulse quality | low frequency noise | |
|---|---|---|
| DIB1 | P/M/P/P | very little |
| DIB2 | P/P/M/D | ~1 kHz on pC @ 4 mVpp |
| DIB3 | M/D/P/P | very little |
| 1510 | Apply -4/+4 V, start bkg data run |
|---|---|
| 1528 | Stop data, 0/0 V, flash 30 seconds. |
| 1550 | Apply -4/+4 V, start bkg data run |
| 1607 | Stop data, 0/0 V, flash 30 seconds. |
| 1647 | look at noise again: |
| low frequency noise | |
|---|---|
| DIB1 | 1 kHz pD @ 5 mVpp, 200 Hz pD @ 4 mVpp |
| DIB2 | 1 kHz in pC @ 5 mVpp |
| DIB3 | 200 Hz pD @ 6 mVpp |
| 1654 | Apply -4/+4 V, start bkg data run. Rate bogs down to ~2 Hz at some point. |
|---|---|
| 1607 | Stop data, 0/0 V |
| 1713 | Bake detector |
| 1752 | Fill Ln2 cold trap full. |