| Status | Run 74 in progress. |
| | Setup: DIB1/2+acc → SL 41/43 → 3.2 MHz filters → cables 2/3 → nothing/nothing → DCRC50(3)/55(1). No lead/poly shield. |
| 0910 | MB = 69.0% |
| 0940 | Tower = 91.8 mK. |
| 1050 | Noise is high-ish today. At 10kHz noise in DCRC3qI/qO/DCRC1qI/qO = 13/1.3/79/3.5 e-6. In q4 (always the worst one) it's about 8X higher now then yesterday. |
| | Last time the noise got better after applying bias for a data series and then flashing. Let's try that. |
| 1055 | Apply +11V bias from the DCRCs |
| 1125 | Set bias back to 0V |
| | Noise looks the same. Let's try flashing. |
| 1130 | Flash LEDs on DCRCs1&3 for 30 seconds |
| 1240 | Tower has cooled to 93.0 mK. Noise has not improved. |
| 1443 | Derek enters lab |
| 1446 | Tower/MC/Coldplate = 92.2/31.4/187 mK, Still = 1.45 K / 0.130 mbar / 0 mW, G1/G2 = 250/223 mbar, 1K Pot = 1.67 K / 36±2 mbar. |
| 1448 | Fill LN2 cold trap bath. |
| 1515 | Shut down DAQ programs, unplug DCRC55(1), plug Cable 3 into breakout box. Check qI/qO bias: around 6 nS. Check Side2 to qI and qO - less than 0.1 nS. |
| | We'll warm up the tower to do an actual check of the continuity. Previous experience suggests that we need to warm to a few K. |
| 1515 | Close V6 to stop circulation. Turn on MC heater to 10 uW |
| 1520 | Increase MC → 100 uW. Starting to see the temperature go up. |
| 1530 | Tower = 0.4 K. qI/qO = 5 nS. Side2/qI=Side2/qO = <0.1 nS. |
| | Pump outlet and condenser pressures falling, Still pressure rising. |
| 1530 | Increase MC power → 10 mW |
| 1537 | MB = 59.4 % |
| 1540 | Hook up the Fluke multimeter to Side2/qI and put the lab camera on it and shine a light on it, to view remotely. |
| 1545 | Derek exits lab |
| 1545 | Tower = 1.73 K. Side2/qI = 0.07 nS. |
| 1550 | Increase MC power → 20 mW |
| | Checking continuity measurement versus temperature in Run67. With Tower at 3.27 K and lower, it read around 0.07 nS. The lowest temperature with a higher reading than that was Tower = 3.35 K, Side2/qI = 0.15 nS. And it rose sharply at higher temperatures. |
| 1600 | Tower = 2.21 K. Side2/qI = 0.07 nS. |
| | not sure how much higher we can heat it with the 1K Pot on. It looks like it may have hit maximum. |
| 1615 | Fluke multimeter shut itself off. Derek checked a bit to see if one of the digital desktop meters would measure nS resistances but we couldn't find a mode for that, I think he tried the HP one, didn't try the Keithley. |
| | Condenser pressure hit a minimum of 70 mbar and is now increasing, we'll have to keep an eye on it. |
| 2010 | Mostly the Tower has remained below 2.5 K. It has been waving up and down. There was one excursion that went up to 3.5 K then back down. |
| | Condenser pressure has oscillated too but has stayed below 150 mbar. Let's turn off the MC heater for the night. |
| 2015 | Turn off MC heater |