2021/06/21 (Monday)
- 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. | |
| 1400 | Tower/MC/Coldplate = 140/31.1/196 mK, Still = 1.41 K / 0.080 mbar / 0 mW, G1/G2= 172/167 mbar, 1K Pot = 1.64 K / 24±2 mbar. MB= 25.5% |
| Tower thermometer reading has dropped again. Coldplate and Still are back in their high mode. | |
| 1410 | At 10kHz noise in DCRC3qI/qO/DCRC1qI/qO = 21/3.0/2.6/44 e-6. This is q3/q1/q4/q2 At 3kHz (peak) noise in DCRC3qI/qO/DCRC1qI/qO = 1300/170/110/1900 e-6 |
| These are all a little lower than Friday but still not great. | |
| Had trouble starting LHe transfer because stopper got stuck in the transfer lance | |
| 1529 | Begin LHe transfer @ MB = 22.1% |
| 1604 | End LHe transfer @ MB = 61.0 % |
| 1610 | Finally figured out how to get the Arduino connection back. After starting Arduino Create Bridge, then going to the Arduino Web Editor, selecting Monitor doesn't show a connection immediately. You have to select COM4 from the dropdown menu at top, then close and reopen the Monitor. Now it's working. |
| 1620 | Fill LN2 cold trap bath |
| 1620 | The Arduino is powered and plugged into the spare, warm motor. GwINSTEK power supply is set to 7.2 V. On Monitor tab type Help to remind myself of the commands. Try some moves on the spare motor - it works. |
| 1705 | Refer to October 28 run diary to understand how to set up the scope to view waveforms, V and I, from driver to motor coil. We set up a breadboard to connect the external motor to the driver, and also put 100 Ohm resistors in series with each coil. Use scope Channel 1 to read across coil and Channel 2 to read across resistor. Set time scale to 100 ms and press Single Seq to trigger once and save. |
| At some point we did rd dwell, got 15, then changed to the standard 40 with wr dwell 40. This changes the period of the waveform. | |
| 1715 | Reconnect the source mover wires to the stepper motor driver board. Note - I powered off the driver board (turned off GwINSTEK power) but left the Arduino powered, then plugged in the motor wires, then turned the GwINSTEK power back on. I think we are still connected to the Arduino, and I didn't see a temperature spike yet. |
| 1800 | OK I think I have the scope set up to read channel 1: voltage across one coil and channel 2: voltage across that coil's trim pot. |
| 1800 | MC/Tower = 31.1/160 mK |
| 1800 | I was about to try a move but we had lost connection to the Arduino, so I reestablished that, then got a temperature spike. Should have tried powering off the driver board then reconnecting to the Arduino. MC peaked at 95 mK, now cooling. |
| 1803 | MC/Tower/MC = 68.7/430/61.0 mK, cooling |
| 1810 | MC = 42.8 mK, still cooling. Let's go ahead and try a move. |
| 1810 | Do mv +4 MC peaks at 63 mK then starts cooling. Not all that high. I had the scope timescale set too long, so didn't see the full waveform. I think I have Channel 2 across the trim pot, but the voltage across it seems low compared to what I'd seen before, and noisy.  |
| 1815 | MC = 45.2 mK and cooling |
| 1815 | Do mv +8 Got a better picture on the scope this time MC peaks higher, 81 mK  |
| 1818 | MC/Tower/MC = 75.0/1220/71.1 mK |
| 1821 | MC/Tower/MC = 62.5/715/58.0 mK |
| 1822 | Do mv +16 Scope suggests that we are not yet losing any current. MC peaks at 108 mK  |
| 1824 | MC/Tower/MC = 104/1420/98.0 mK |