2019/11/13 (Wednesday)
| Setup | DIB1/2/4 → 3.2 MHz filters → cable 1/2/3 → gender changer 1/2/3 → movable source controller/board with external Feedback resistor/nothing → DCRC55(1)/DCRC33(2)/DCRC50(3) |
|---|---|
| 0935 | Tower/MC/Coldplate = 35.8/30.6/192 mK, Still = 1.53 K/ 0.130 mbar / 0 mW, G1/G2= 195/184 mbar, 1K Pot = 1.66 K / 32±2 mbar. MB= 28.8% |
| 0938 | Fill LN2 cold trap bath. |
| 0947 | DCRC3pD has been railing all the time, SQUID might be in a bad place. Look at modulation curve of DCRC3pD SQUID, indeed, the lockpoint is somewhat close to the top of the curve. Reduce DCRC3pD lockpoint from -2.53 to -4.0 to lock near the middle of modulation curve. |
| 0955 | Start 1x S1/S2=+4/-4,-4/+4 V loop of 30 min Bkg data series with lower DCRC3pD lockpoint, Driver gain = 1, with 1000 initial randoms, with 30s flashes and 30 min cooldowns trigger on DCRC2pA/B/C = 8/8/8 ADC using sequence qbias_pm4_mp4_loop.msl |
| 1148 | Data from yesterday indicates phonon collection efficiency has decreased since the latest source move. Let's do a strong LED flash to try and reset the aluminum fins. |
| 1200 | Run the sequence Al_flash.msl to flash for 1 min with LEDPulseWidth/LEDRepRate/LEDCurrent = 400 us/500 us/0.8 mA. Tower spikes to 1.295 K. |
| 1205 | Tower = 245 mK |
| 1213 | Tower = 91.6 mK |
| 1315 | Tower = 36.6 mK |
| 1325 | Tower temperature seems to be settling a little high, 36.6 mK, about 0.8 mK higher than current base. Channels mostly look OK, no breakdown seen, a few railed phonon channels. |
| 1330 | Start LHe transfer, MB=21.6% |
| 1432 | Cease LHe transfer, MB=93.4% |
| 1436 | Tower = 35.8 mK |
| 1441 | Start 1x S1/S2=-4/+4 V series of 30 min Bkg data series with lower DCRC3pD lockpoint, Driver gain = 1, with 1000 initial randoms, with 30s flashes and 30 min cooldowns trigger on DCRC2pA/B/C = 8/8/8 ADC using sequence take_and_flash_loop.msl |
| 1536 | Looks like the Al flash restored phonon signal amplitudes to ~90% of their values pre-move. This is comparing +/-4 V data from series 07191112_1500, 07191113_1056, and 07191113_1441 |
| Relative PCE | ||||||
|---|---|---|---|---|---|---|
| Side 1 | after move | after Al flash | Side 2 | after move | after Al flash | |
| pA | 0.31 | 0.94 | pA | 0.26 | 0.81 | |
| pB | 0.3 | 0.87 | pB | 0.32 | 0.87 | |
| pC | 0.31 | 0.95 | pC | 0.33 | 0.91 | |
| pD | 0.31 | 0.96 | pD | 0.37 | 0.8 | |
| pE | 0.28 | 0.9 | pE | 0.29 | 0.96 | |
| pF | 0.39 | x | pF | 0.37 | 0.81 | |
This data after the Al flash shows the side 2 phonon y-partition has come back down.
| 1542 | Power arduino and connect to it via telnet. Then turn on the motor controller power supply to 8V. Set the dwell to 8 ms. Set the current step position with wr currstep 356. |
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| 1546 | Move to step 500 with command mvto 500. Tower spikes to 1.8 K. Also have the oscilloscope connected across both the motor coils to monitor voltage. The signal on coil A is a series of 6V square pulses as expected, but that on coil B is a series of sharp spikes instead of the expected square wave drive signal. Disconnect from and power down arduino and motor power supply. |
| 1557 | Tower = 119 mK |
| 1605 | Check the probe connections on motor coil B, indeed we weren't connected properly, so it's no surprise we didn't see the motor drive signal. |
| 1606 | Tower = 65.4 mK |
| 1720 | Tower = 36.9 mK. Still more than 1 mK above base. It's been 1 hour 35 min since the move. Looks like it'll take around 2 hours total to cool to base. |
| 1727 | Fill LN2 cold trap full. |
| 1754 | Tower = 36.1 mK |
| 1755 | Start 1x S1/S2=+4/-4,-4/+4 V loop of 30 min Bkg data series with lower DCRC3pD lockpoint, Driver gain = 1, with 1000 initial randoms, with 30s flashes and 30 min cooldowns trigger on DCRC2pA/B/C = 8/8/8 ADC using sequence qbias_pm4_mp4_loop.msl |
| 2005 | Run the sequence Al_flash.msl to flash for 90 sec with LEDPulseWidth/LEDRepRate/LEDCurrent = 400 us/500 us/0.8 mA. Tower spikes to 1.5 K. |
| 2114 | Tower = 36.9 mK |
| 2146 | Tower = 36.0 mK, channels look fine. |
| 2148 | Start 4x S1/S2=+4/-4,-4/+4 V loop of 30 min Bkg data series with lower DCRC3pD lockpoint, Driver gain = 1, with 1000 initial randoms, with 30s flashes and 30 min cooldowns trigger on DCRC2pA/B/C = 8/8/8 ADC using sequence qbias_pm4_mp4_loop.msl |
Again, immediately after the move, the phonon Y partition goes a little positive, but after the Al flash, it comes back down.
