2022/03/28 (Monday)
- Lab in-personnel: Matt, Anthony, Kitty, Scott
| Status | Run 76 in progress |
|---|---|
| Setup | Cable 2/1/3 → diverter/nothing/nothing → DCRC55(1)/DCRC50(3)/DCRCX(4), DCRC55(1) is off. |
| 1005 | MC/Coldplate = 26.9/140 mK, Still = 1.08 K / 0.120 mbar / 0 mW, G1/G2= 182/161 mbar, 1K Pot = 18° / 1.66 K / 28±2 mbar, MB = 65.3% |
| 1005 | Goldman = 71.5 mK @ 632 uV excitation |
| 1010 | Fill LN2 cold trap bath |
| 1020 | Currently looking at channels on DCRC3(Cable1) and DCRC4(Cable3). All pulses look good. Haven't been able to get pulses on Cable2, have mostly tried with DCRC1 - also tried DCRC5 and DCRC6, those are also acting strangely. |
| 1025 | Turn off DAQ programs and power down DCRC3. We'll try it on Cable2. |
| 1025 | Reset ODB Lockpoint and SQUIDbias values on DCRC3 to what they should be for Cable2 |
| 1030 | Connect Cable2+diverter to DCRC3, power up DCRC3, turn on DAQ programs. |
| 1040 | Good pulses on all Cable2/DCRC3 channels with QET biases 300/280/300/220 uA. Good - this means the previous problem was with the DCRC and not the SQUET or cable or diverter board. |
| 1055 | MC temperature has risen a little, from 26.8 to 28.0 mK |
| Source mover tests: | |
| 1100 | On Fridge computer, put 2D source mover software on taskbar: NPA PMX-2ED-SA. Plug in controller power supply, plug USB from controller into computer, try starting software - it works. (This is without connecting the coil wires from the diverter board to the controller.) |
| 1105 | Disconnect USB from fridge computer, we'll use the laptop instead for the initial tests. |
| 1110 | Run Set Absolute Positions.prg. This sets the software to know what the initial position is: X0 Y96 (source at center). Remember to 1) load program 2) compile 3) download 4) run. |
| 1115 | Run X and Y set ABSOLUTE.prg. This has updated speeds, HSPD 10 LSPD 5, changed during tests with mover in the tower connected to the striplines at room temperature. Just run it to X0 Y96, no move. |
| 1120 | Check coil resistances at the connectors once again: 31/31/21/31 Ohms, all good. |
| 1125 | Plug motor coil connectors into the controller. Watching DCRC3pC, see that this produces some high-frequency spikes in the noise (lowest one is 63 kHz). |
| 1125 | Run X and Y set ABSOLUTE to X0 Y96. Expect this to move the source from its slightly offset position after installation to true center. MC temperature rises to 0.4 K in a couple minutes. Goldman reads 2.1 K, cools to 1.8 K in a couple minutes. MC peaked somewhere around 0.5 K then started cooling again. |
| 1130 | MC has cooled to 0.35 K, then plateaus for a few minutes. Then starts cooling again. |
| 1150 | MC = 71 mK and cooling. |
| Condenser (G1) rose from 180 to 240 mbar, then fell again. Still rose from 0.12 to 0.2 mbar then fell again. | |
| 1155 | Run X and Y set ABSOLUTE to X0 Y96 a second time. This time we don't expect a physical move. MC temperature rises similarly to before - peaks at 0.49 K after a couple minutes, then starts cooling. It also has the same plateau around 0.35 K for a few minutes before cooling again. |
| Could the plateau be related to the 1.2 K Al s/c transition? If we can trust the Goldman thermometer in this range, the plateau seems to occur when Tower is between about 1.6 and 1.2 K. | |
| 1310 | MC = 30 mK and falling |
| 1330 | MC = 28.8 mK and falling. Pulses are back on DCRC3(Cable2) but they look significantly wider than before. Could just be that the detector is warmer (should check Goldman thermometer) or it could be evidence that the move produced trapped flux in the fins and we need to do an Al-flash. |
| 1340 | Goldman = 76.5 mK @ 632 uV excitation, seems to be cooling slowly. This is not a huge difference from earlier today, so the wideness seen in the pulses could very well be trapped flux. |
| 1345 | Goldman = 76.1 mK, definitely cooling. Adjusted pA QET bias down a bit, now pulses don't look wide. Other pulses look kinda normal too. So not sure there's any evidence of trapped flux. |
| 1445 | Goldman = 74.0 mK, still steadily cooling. Still a few mK warmer than this morning. MC = 28.4 mK, still cooling slowly. |
| 1450 | Turn off DAQ programs, then plug Cable1 into DCRC1 and turn on power. |
| 1455 | Set phonon parameters (lockpoints, SQUID biases, QET biases) on DCRC1 to the Cable1/DCRC3 settings from before. Enable DCRC1 only, start DAQ programs. |
| 1500 | Seeing pulses on all DCRC1 channels - adjust QET biases down a bit and they look nice and strong. So, DCRC1 is now working on Cable1. |
| 1510 | Fire up all 3 DCRCs in this configuration: Cable 2/1/3 → diverter/nothing/nothing → DCRC50(3)/DCRC55(1)/DCRCX(4). Seeing pulses in most channels though some look ugly - let's zap SQUIDs. |
| 1510 | Zap SQUIDS on DCRCs 1,3,4 |
| 1540 | Got good pulses in all 12 channels now - good! [image not archived: cool.svg] |
| 1640 | MC = 28.8 mK and flat. Goldman = 73.6 mK @ 632 uV excitation, also seems pretty flat. |