2017/01/26 (Thursday)
| Setup: DIB1/3/4 → 3.2 MHz filters → cables → DCRC55(1)/33(2)/50(3) | |
| 0840 | Fill LN2 cold trap. |
| 0845 | Tower/MC/Coldplate = 62.0/33.2/192 mK, Still = 1.2 K / 0.110 mbar, G1/G2 = 131/129 mbar, 1K Pot = 1.70 K / 32 mbar, Main bath = 71.3%. |
| 1150 | Measure rate by counting pulses in 10*100ms traces on DIB1PA: 70Hz |
| 1200 | Try to measure rate in channel below source (DIB4PB) but find the channel does not respond to changes in QET bias. |
| Channel Roll Call | ||||
|---|---|---|---|---|
| DIB | Channel | Responds to QET bias changes | Responds to Test signal on FB | Notes |
| DIB1PA | Side1 pE | yes | yes | |
| DIB1PB | Side1 pB | yes | yes | |
| DIB1PC | Side1 pD | yes | yes | |
| DIB1PD | Side2 pE | yes | yes | |
| DIB3PA | Side2 pB | yes | no* | Unresponsive to QET bias on Friday Jan 27 |
| DIB3PB | Side2 pA | yes | no* | |
| DIB3PC | Side1 pA | yes | ||
| DIB3PD | n/c | slightly | ||
| DIB4PA | Side2 pC | no | no | |
| DIB4PB | Side2 pF | no | no | Responsive to QET bias using DCRC1 on Friday Jan 27. But not on Monday Jan 30. |
| DIB4PC | Side1 pC | yes | Only weak pulses seen using DCRC1 on Friday Jan 27. Pulses look okay as of Feb 8. | |
| DIB4PD | Side1 pF | yes | ||
| *This may not be functional on DCRC33 |
This seems to indicate that a couple of channels that should be connected, DIB4 pA and pB, are maybe open, because there is no change in signal with a change in QET bias. We tried looking at the test signal in feedback directly as a check of whether the DCRC seemed to be working for these channels, but we became a bit confused as to what we should see.
| 1245 | Try IbIs at low biases on DCRC1pA. Up to 50 uA it looks like a standard s/c slope: calculated Rpar = 10.4 mΩ. |
|---|---|
| 1300 | Try applying test signals to DCRC1 QETs, 12 mVpp/100 Hz. At first DCRC1pA looked reasonable: output 22 mVpp, with driver gain 1x so this is around 10 mΩ. But DCRC1pC and pD show some pulses as if they are in transition… and looking later at DCRC1pA it's output is much lower, 8 mVpp → 70 mΩ, so it seems to have been driven normal. |
| 1310 | MB = 64.9 %. Boil off rate: faster than slow mode but not much. |
| 1525 | Try a different method for Tc. Set all DCRC1 QET biases to 10 μA. All seem to be superconducting. Driver gains = 1x. By watching the baseline you should see a change when the TES goes normal, the baseline should rise significantly (if Rpar = 10 mΩ and Rn+Rpar = 70 mΩ then baseline should rise by more than 100 mV). Between s/c and normal there should probably be a transition region in which pulses are seen. |
| 1530 | Tower = 60.9 mK. |
| 1600 | This method seemed to work. Applying 5-8 μW to the MC heater, scanned through a tower temperature range of 61-73 mK; all the transitions temperatures were in this range. Scanned up and down, could see the move into transition (pulses appear, baseline rises) and into normal (pulses mostly disappear, baseline reaches a maximum). Scanned up and down and recorded the data below. All Tc's on the DIB1 channels are between 68 and 71 mK. |
| S101 Critical Temperatures | |||||
|---|---|---|---|---|---|
| DIB chan | Side chan | SC → Transition [mK] | Transition → Normal [mK] | Normal → Transition [mK] | Transition → SC [mK] |
| DIB1 pA | Side1 pE | 65.8 | 68.7 | 69.3 | 69.3 |
| DIB1 pB | Side1 pA | 67 | 70.4 | 69.4 | 70.2 |
| DIB1 pC | Side 1 pD | 70 | 72.1 | 72.2 | 71.7 |
| DIB1 pD | Side 2 pE | 69.3 | 71.2 | 71.1 | 71 |
| 1630 | Fill LN2 cold trap bath |
|---|---|
| 1635 | Tower = 60.8 mK |
| 1635 | MB = 59.9% |