2021/06/22 (Tuesday)
- Lab in-personnel: Matt, Derek
| Status | Run 74 in progress. First cooldown after IVC rebuild. |
|---|---|
| Tower thermometer is reading high, probably this is a thermometer problem and the actual temperature is much lower. High noise in some of the charge channels. | |
| Setup: DIB1/2+acc → SL 41/43 → 3.2 MHz filters → cables 2/3 → nothing/Source_mover_board+HV_diverter_board → DCRC50(3)/55(1). Kepco 40V supplye → HV BNC. No lead/poly shield. | |
| 1122 | Tower/MC/Coldplate = 191/31.2/196 mK, Still = 1.41 K / 0.080 mbar / 0 mW, G1/G2= 182/173 mbar, 1K Pot = 1.64 K / 24±2 mbar. MB= 37.1% |
| 1123 | Fill LN2 cold trap bath. |
| Let's do more source mover tests like yesterday | |
| 1135 | Do mv +32 MC rises quickly to 80 mK, then continues to rise - looks like there was more bulk heating this time Waveforms don't show any indication that current fell off during move.   |
| 1138 | MC/Tower/MC = 92.6/1760/93.3 mK |
| 1140 | MC peaks at 94 mK, then starts cooling. Tower = 1.29 K and cooling. |
| 1145 | MC = 60 mK and cooling. Tower = 680 mK and cooling. |
| 1155 | MC = 41 mK and cooling. Tower = 353 mK and cooling. |
| 1215 | MC = 32.6 mK and cooling. Tower = 236 mK and cooling. |
| 1220 | Do mv +64 MC rises quickly to 107 mK, then continues to rise - looks like there was more bulk heating this time Waveforms don't show any indication that current fell off during move.   |
| 1222 | MC/Tower/MC = 133/2420/139 mK. MC peaks at 139 mK then started cooling. |
| 1215 | MC = 106 mK and cooling. Tower = 1.49 K and cooling. |
| 1255 | MC = 34 mK and cooling. Tower = 316 mK and cooling. |
| The fridge did not react particularly strongly to the last long move. Circulation pressures rose by about 5% over about 15 minutes then started falling again. Still pressure rose 0.08→0.09 mbar then fell again. No effect on 1K Pot. | |
| 1310 | MC = 32.6 mK and cooling. Tower = 267 mK and cooling. |
| 1310 | Do mv +128 MC rises quickly to 140 mK, then continues to rise Waveforms don't show any indication that current fell off during move.    |
| 1312 | MC/Tower/MC = 201/3270/214 mK. MC peaks at 214 mK then starts cooling. |
| 1328 | Begin LHe transfer. MB = 34.0% |
| 1330 | MC = 56 mK and cooling |
| 1405 | End LHe transfer @ MB = 64.3% |
| OK let's do another couple of 128 step moves, but with less time between them. A 128-step move is 2.11 mm. | |
| 1415 | MC = 31.9 mK and cooling. Tower = 222 mK and cooling. |
| note: Arduino Live Editor keeps losing connection periodically. To restore it: 1) turn off GwINSTEK power output to motor driver 2) reload editor tab 3) choose Arduino Uno COM4 from dropdown 4) click Monitor - it should say Hello 5) turn GwINSTEK power output back on | |
| 1420 | MC = 31.5 mK and flat. Tower = 208 mK and cooling. |
| 1420 | Do mv +128 MC rises quickly to 138 mK, then continues to rise Waveforms look ok, same as before. |
| 1423 | MC/Tower/MC = 219/3110/225 mK. MC peaks at 225 mK then starts cooling. |
| 1427 | MC = 191 mK and cooling. Tower = 1.66 K and cooling. |
| 1430 | MC = 126 mK and cooling. Tower = 1.08 K and cooling. |
| 1430 | Do mv +128, 10 minutes after the last one MC rises quickly to 187 mK, then continues to rise Waveforms look ok, same as before.    |
| 1435 | MC peaks at 263 mK. Tower = 2.45 K and falling. |
| 1443 | MC = 113 mK and cooling. Tower = 1.09 K and cooling. |
| 1444 | Do mv +128, 11.7 minutes after the last one MC rises quickly to 173 mK, then continues to rise Waveforms look ok, same as before.    |
| 1446 | MC peaks at 248 mK. Tower = 3.01 K and falling. |
| We have now theoretically moved the source 10.51 mm. The near endstop is at 13.12 mm, so we are getting closer to it. The other endstop is at -41.35 mm so that will take longer. | |
| Looks like the Tower temperature peaked higher with each of these last 3 moves (+128 steps every 10 minutes). So not sure we could continue at this rate without a runaway. Note that this rate is 12.66 mm/hour, a lot better than the 1 mm/hour we got in past runs. During these steps, circulation pressures rose 17% (G1/G2 peaked at 217/205 mbar). Still rose up to around 0.11 mbar. |
|
| 1458 | MC = 84 mK and cooling. Tower = 0.86 K and cooling. |
| 1504 | MC = 62 mK and cooling. Tower = 0.65 K and cooling. |
| 1505 | Do mv +128. MC rises quickly to 141 mK, then continues to rise Waveforms look ok, same as before. |
| 1508 | MC peaks at 232 mK. Tower = 2.68 K and falling. |
| Source has theoretically moved 12.62 mm, 0.50 mm from near endstop assuming it is heading in that direction. | |
| 1517 | MC = 100 mK and cooling. Tower = 0.98 K and cooling. |
| I've been checking far- and near-endstop to DCRC ground, they're 0.2 nS or less. | |
| We'll do a 20-step move next to get closer to the near endstop distance. | |
| 1522 | MC = 71 mK and cooling. Tower = 0.72 K and cooling. |
| 1524 | Do mv +20. MC rises quickly to 87 mK, then continues to rise Waveforms look ok, same as before. |
| 1526 | MC peaks at 96 mK. Tower = 1.35 K and falling. |
| Endstop-to-chassis still open. Theoretically 0.17 mm from near endstop distance | |
| 1531 | MC = 72 mK and cooling. Tower = 0.82 K and cooling. |
| 1533 | Do mv +8. MC rises quickly to 76 mK, then continues to rise a little Waveforms look ok, same as before. |
| 1534 | MC peaks at 76 mK. Tower = 1.07 K and falling. |
| Endstop-to-chassis still open. Theoretically 0.04 mm from near endstop distance | |
| 1539 | MC = 61 mK and cooling. Tower = 0.72 K and cooling. |
| 1540 | Do mv +8. MC rises quickly to 68.0 mK, then continues to rise a little Waveforms look ok, same as before. |
| 1543 | MC peaks at 69.6 mK. Tower = 1.02 K and falling. |
| Endstop-to-chassis still open. Theoretically 0.09 mm past near endstop distance | |
| 1548 | MC = 52 mK and cooling. Tower = 0.58 K and cooling. |
| 1550 | Do mv +8. MC rises quickly to 61.9 mK, then continues to rise a little Waveforms look ok, same as before. |
| 1552 | MC peaks at 64.9 mK. Tower = 0.95 K and falling. |
| Endstop-to-chassis still open. Theoretically 0.22 mm past near endstop distance | |
| 1559 | MC = 46 mK and cooling. Tower = 0.50 K and cooling. |
| 1601 | Do mv +16. MC rises quickly to 68.2 mK, then continues to rise a little Waveforms look ok, same as before. |
| 1604 | MC peaks at 76.8 mK. Tower = 1.18 K and falling. |
| Endstop-to-chassis still open. Theoretically 0.49 mm past near endstop distance | |
| 1610 | MC = 55 mK and cooling. Tower = 0.60 K and cooling. |
| 1611 | Do mv +32. MC rises quickly to 93.8 mK, then continues to rise a little Waveforms look ok, same as before. |
| 1614 | MC peaks at 108 mK. Tower = 1.45 K and falling. |
| Endstop-to-chassis still open. Theoretically 1.02 mm past near endstop distance | |
| 1622 | MC = 64 mK and cooling. Tower = 0.63 K and cooling. |
| 1623 | Do mv +64. MC rises quickly to 120 mK, then continues to rise Waveforms look ok, same as before. |
| 1625 | MC peaks at 140 mK. Tower = 1.85 K and falling. |
| Endstop-to-chassis still open. Theoretically 2.07 mm past near endstop distance | |
| so either we're moving toward the far endstop, or we're not moving as far as we think we are |