2017/07/05 (Wednesday)
| Setup: DIB1 → 3.2 MHz filters 1 → cable 1 → gender changer 1 → DCRC55(1) | |
| 0925 | Lab = 22.1 C, 44% humidity |
| 0925 | Tower/MC/Coldplate = 28.3/30.5/180 mK, Still = 1.3 K / 0.060 mbar, G1/G2 = 117/113 mbar, 1K Pot = 1.68 K / 26 mbar. MB = 70.0% |
| 0930 | Fill LN2 cold trap bath |
| 1000 | DIB1 pA and pC were showing pulses on Monday. Today pA looked like it had fallen into s/c so I bumped its QET bias up and pulses are back. Currently pA/pC are at 50/55 uA. |
| 1020 | Check DIB1 pB, which doesn't show pulses. At QET bias = 0/5 uA, Vout = 0.0145/0.0135 V. This is with Driver Gain x1 on DCRC1 (so fixed gain x2). This implies Rtes+Rpar of 3.08 Ohm. Looks like it's normal. But this seems like a surprisingly high Rnormal. |
| 1025 | Measure Rtes+Rpar on the two good channels pA and pC, same method but use higher QET bias range, 100-110 or 120-130 uA. pA = 92.2 mOhm, pB = 109.1 mOhm. So something else is apparently wrong with pB. Also check pD: looks like aroun 260 mOhm. |
| 1035 | Measure Rpar in pA/pC by comparing QET biases of 0 and 10 uA. Result: 9.1/8.3 mOhm. |
| DIB1 Rnormal/Rparasitic | |||
|---|---|---|---|
| Rnormal+Rpar [mOhm] | Rpar [mOhm] | Rnormal [mOhm] | |
| pA | 92.2 | 9.1 | 83.1 |
| pB | 3080 | ||
| pC | 109.1 | 8.3 | 100.8 |
| pD | 260 | ||
| pB and pD seem to have anomalously high resistances even at QET bias = 0 | |||
| 1050 | Disconnect DIB1 and connect DIB3 to DCRC1. Apply appropriate SQUID settings. Zap SQUIDs. |
|---|---|
| 1100 | Seeing pulses on DIB3 pA/pB/pD at 40/80/55 uA. On pA they seem weaker - this is the channel with the strong short to chassis. On pC there's no response to changes in QET bias, implying R>150 Ohm - this is the channel that occasionally read open, so it's probably open now. |
| 1230 | Finish Tc check on DIB3 pA/pD. Heated tower as high as 60 mK by applying up to 13 uW power to heater. Saw pD go into and out of transition both warming and cooling, pA only on cooling (at first it seemed that the test signal was too weak to see). DIB3 pA (Side2 pA) : 48.8 - 51.8 mK (cooling) DIB3 pD (Side1 pC) : 47.0 - 49.7 mK (warming), 48.0 - 49.4 mK (cooling) Somehow it didn't work on pB, it looked like it was in the normal state throughout the temperature scan. |
| 1255 | Managed to get pB into s/c with a test signal, and repeated temperature scan. It was a little confusing because while heating it seemed to go into transition at 56.3 mK and back out at 57.2 mK, but when it came out it looked like it was still s/c. Then I saw another transition at higher temperature which I assume is the correct one. DIB3 pB (Side2 pC) : ? - 59.5 mK (warming), 60.1 - 61.3 mK (cooling) |
| 1320 | Estimate Rpar and Rnormal for the working channels. |
| DIB3 Rnormal/Rparasitic | |||
|---|---|---|---|
| Rnormal+Rpar [mOhm] | Rpar [mOhm] | Rnormal [mOhm] | |
| pA | 118 | ? | ? |
| pB | 81.1 | 10.2 | 70.9 |
| pC | >900,000 | ||
| pD | 123.3 | 17.3 | 106 |
| pA, the one with the bad short, has nonsensical IbIs behavior at low (s/c) biases. Vout moves very little, so that R looks like 526 mOhm from 0-10 uA and 918 mOhm from 20-25 uA. |
|||
| 1335 | Disconnect DIB3 and connect DIB4 to DCRC1. Apply appropriate SQUID settings. Zap SQUIDs. |
|---|---|
| 1350 | Got pulses on DIB4 pB/pC/pD with QET biases of 80/65/55 uA. But pA is railed low and can't be brought into range with any driver offset (although you can see the trace in “open” polarity). pB required an unusually low offset of -1.1 V. This seems like the DCRC is in a “bad state” so I'm powercycling it. |
| 1355 | Zap DIB4 SQUIDs |
| 1410 | Powercycling the DCRC didn't improve things. Tried retuning the SQUID on DIB4pA to -70.6/-1.8 SQUID bias/lockpoint. Now it can be adjusted into range though it still requires a strong negative offset. See pulses with QET bias of 55 uA. So all 4 channels on this DIB are working. |
| 1455 | Finish Tc scan on DIB4, heating to maximum 63 mK, maximum MC heater power of 14.5 uW. pD looked a little strange because the triangle output amplitude was much smaller than the others. Missed the transitions while heating, saw them better while cooling. DIB4 pA (Side2 pE) : 59.3 - 59.5 mK (cooling) DIB4 pB (Side2 pF) : 62.3 - 62.9 mK (cooling) DIB4 pC (Side2 pD) : 58.5 - 59.4 mK (cooling) DIB4 pD (Side1 pB) : 54.5 - 56.5 mK (cooling) |
| 1615 | Attach DIB3 to DCRC2, for now. First apply the appropriate SQUID settings. This is for Anthony to do some DAQ testing. |
| 1620 | Got some pulses on DCRC2 pB and pD. |
| 1622 | Zap DIB3 SQUIDs (DCRC2). |
| 1635 | Fill LN2 cold trap bath |
| G132 Critical Temperatures |
|---|
 |