2015/09/15 (Tuesday)
| Current setup: HV mode, DIB1/2/3 → cables → 3.2 MHz filters → HV box 1/2 → DCRC50/55. | |
| Overnight: idle, no source | |
| 0935 | Fill LN cold trap Dewar |
| 0940 | Tower/MC(H35)/MC sensor/Cold Plate = 30.6/24.3/43.4/152 mK, Still = 1.27 K / 0.080 mbar, G1/G2 = 150 mbar, 1K Pot = 1.72 K / 24 mbar |
| 1015 | Repeat yesterday's standard-bias baseline versus HV test for negative HV: |
| HV1pA baseline (std. QET bias, 93.2 μA) | |||
|---|---|---|---|
| HV (V) | I_leak (nA) | Baseline (V) | notes |
| 0 | -0.1 | 0.065 | |
| -14 | -24.1 | 0.065 | |
| -15 | -25.3 | 0.065 | |
| -15.4 | -26 | 0.08 | |
| -16 | -26.4 | 0.08 | |
| -16.4 | -26.9 | 0.1 | |
| -16.8 | -28.8 | 0.12 | |
| -17.2 | -29.1 | 0.13 | |
| -17.6 | -30 | 0.15 | |
| -18 | -30.4 | 0.18 | |
| -18.4 | -30.9 | 0.22 | |
| -18.8 | -32 | 0.27 | |
| -19.2 | -32.9 | 0.32 | |
| -19.6 | -33.6 | 0.34 | pulses almost gone |
| -20 | -34.4 | 0.34 | pulses completely gone |
| 1030 | At HV = -31 V / -56.7 nA (near max for small supply), Tower temperature increases from 30.5 to 31.4 mK. |
|---|---|
| 1040 | Disconnect DCRCs and remove HV box. |
| 1045 | Connect DCRCs, zap, apply settings. |
| Current setup: iZip mode, DIB1/2/3 → cables → 3.2 MHz filters → → DCRC55/33/50. | |
| 1114 | Main bath = 61.0% |
| 1130 | All frontend gains set to 1, output gains still set to 3. |
| 1208 | Midas tests of zapping and flashing. |
| 1600 | Commence Midas flashing tests. |
| 1620 | Set up phonon channels with DCRC 55/33/50 having Frontend Gain= 5/2/5 and Output Gain= 3/3/3. New driver offsets listed below: |
| A | B | C | D | |
|---|---|---|---|---|
| DCRC55 | 0.116 | 0.024 | 0.020 | 0.030 |
| DCRC33 | 0.024 | | -0.042 | 0.014 |
| DCRC50 | -0.030 | 0.030 | 0.018 | -0.028 |
| 1630 | Set phonon thresholds: |
|---|
| A | B | C | D | |
|---|---|---|---|---|
| DIB1 | 40 | 35 | 45 | 45 |
| DIB2 | 30 | 60 | 25 | 30 |
| DIB3 | 45 | 45 | 45 | 45 |
| 1640 | DIB2pB keeps railing requiring a relock. Looking at the modulation curve, see that the SQUID looks over-biased. Zero all SQUID values and zap SQUIDs. |
|---|---|
| 1655 | DIB2pB still railing every ~60s. Modulation curve looks the same. Power cycle. |
| 1711 | DIB2pB not railing as often after power cycle, but the modulation curve still seems to have resonances. |
| pB railed, but changing driver offset from 0.030 to -0.026 brings it back without a relock. | |
| 1730 | DIB2pB hasn't railed in 20 minutes with the new driver offset. Create new MultiDAQ files for new gains and driver offsets at 0V, -/+4V, and -/+2V. |
| 1740 | Set DAQDAQ2 to take 4 cycles of 15 minute data series of first -/+2V then -/+4V. Frontend gain set to 5/2/5, Output Gain set to 3/3/3. OR trigger across all phonon channels. 1000 initial randoms and 2000 events/file. 30s flash and 30min cooldown in between series. |
| 1745 | Start data series. No external source, alternating -/+2V and-/+4V. |
| 1755 | Fill LN2 cold trap full. |