2015/06/29 (Monday)
| 0830 | Remove Cf source from fridge (was on over the weekend to activate detector) |
|---|---|
| 0836 | Fill LN2 cold trap Dewar |
| 0842 | Stop flashing detector. Note that tower temperature only reached 128 mK during flashing. Turned off the three DIBs in sequence: DIB1 off, 128 mK → 44 mK. DIB2 off, no temperature change. DIB3 off, 44 mK → 34 mK. |
| 0845 | Experimented with DIB2 flashing. Noticed in the PuTTY session that during flashing rd 30 returned 0003, thus FETs were off. Tried flashing from DetectorControl - no temperature change. Tried wr 30 0003 - no temperature change. Tried wr 30 0803 - temperature shoots up >90 mK. Conclusion: at least on DCRC33, LEDs do not turn on unless FETs also turned on. |
| 0900 | Reduce thresholds to lowest values possible without triggering frequently on noise: |
| Current phonon threshold settings | ||||
|---|---|---|---|---|
| pA | pB | pC | pD | |
| DIB1 | 15 | 20 | 15 | 15 |
| DIB2 | 20 | 15 | 20 | 15 |
| DIB3 | 15 | 15 | 10 | 10 |
| Current FrontendGain/OutputGain(setting)/DriverOffset settings | ||||
|---|---|---|---|---|
| pA | pB | pC | pD | |
| DIB1 | 7/1/-0.018 | 7/1/-0.014 | 7/1/-0.036 | 7/1/-0.024 |
| DIB2 | 7/1/0.034 | 4/1/0.044 | 7/1/0.032 | 7/1/0.030 |
| DIB3 | 7/1/-0.086 | 7/1/-0.022 | 7/0/-0.108 | 7/0/-0.156 |
| 0913 | Set to -4 / +4 V and start bkg data run |
|---|---|
| 0921 | Tower = 31 mK, Still = 2 mW / 0.11 mbar, G1/G2 = 215/210 mbar, 1K Pot = 1.68 K / 15 mbar, Main bath = 36.8% |
| 0930 | Set to 0 / 0 V and flash detectors (all 3 DIBs) for 10 seconds. Temperature peaks around 150 mK |
| 0945 | Tower did not cool all the way, only to 42 mK. Had to turn off DIB3 FETs to make it cool to base. |
| 0952 | Tower = 31 mK. Set -4/+4 V. Start bkg data run |
| 1008 | Stop data, 0/0 V, flash 15 sec. (Note: for DCRC50→DIB3 we are now doing “wr 30 0803” to flash and “wr 30 0” to stop flashing, i.e. turning FETs on and off along with LEDs.) |
| 1018 | With 15 second flash, Tower → 200 mK and it takes 10 minutes to cool below 32 mK |
| 1022 | Set to -4/+4 V. Start bkg data run |
| 1039 | Stop data, 0/0 V, flash 30 sec. |
| 1051 | With 30 second flash, Tower → 242 mK and it takes 12 minutes to cool below 32 mK |
| 1055 | Set to -4/+4 V. Start bkg data run |
| 1118 | Stop data, 0/0 V, flash 30 sec. |
| 1118 | With 30 second flash, Tower → 225 mK and it takes 12 minutes to cool below 32 mK |
| 1137 | Set to -4/+4 V. Start bkg data run |
| 1154 | Stop data, 0.0 V, flash 30 sec. Tower peaks at 243 mK. |
| 1215 | Power down all boards, remove DCRC55 for voltage calibration. |
| 1400 | Power on boards. Zap SQUIDs. Set all SQUID/QET settings to previous values. |
| 1545 | Test flashing with DetectorControl vi. LEDs from all three DIBs work (produce temperature increases). |
| 1549 | Test flashing with PuTTY. Now DIB3 works the same as it used to: you don't have to turn off the FETs to get the LEDs to turn off. |
| 1616 | Several phonons flatline but recovered with relocks. All settings still good with one exception: |
| Updated DriverOffset settings | |
|---|---|
| pB | |
| DIB1 | -0.094 |
| 1627 | Flash for 30 seconds |
|---|---|
| 1641 | Set to -4/+4 V. Start bkg data run. (Note that we are now using properly calibrated bias for DCRC55→DIB1, but it's very close to the nominal setting: to get -4 V in Q1/Q2 requires nominal settings of -3.999/-3.965 V) |
| 1520 | Checked pressure of LHe transfer tube vacuum jacket with external pressure sensor; jacket pressure at 2.5E-2 mbar (including the volume of 3 bellows). Q compound appears to be successfully reducing the leak, though it appears to have been smudged during the previous transfer. Cover Q compound with duct tape to prevent future movement. |
| 1535 | Commence LHe transfer (25.5%). |
| 1415 | End LHe transfer (91.7%). |
| 1730 | Fill LN2 cold trap full. |
| Attach 3.2 MHz Pi Filter to DCRC 55 (DIB1) and 10 MHz C Filter to DCRC 33 (DIB2). Continue studies tomorrow. |