2016/08/15 (Monday)
| Setup: iZIP mode, DIB1/2/3 → 3.2 MHz filters → cables → DCRC55(1)/33(2)/50(3), Tower has been cooled below Al transition with mu-metal shield at standard position | |
| DCRCs powered overnight. Pumping on IVC with turbo pump overnight. | |
| 0855 | Tower/MC/Coldplate = 41.3/30.7/159 mK, Still = 1.33 K / 65 μbar, G1/G2 = 225/200 mbar, 1K Pot = 1.52 K / 4.5 mbar, MB = 81.4%. Boiloff rate: good. Last night's pressure release pattern worked, 5min and 35min after a fill to 92%. |
| 0900 | Fill LN2 cold trap full. |
| 0905 | Six channels are railed this morning, probably last night's data was not so good. |
| 0910 | Restore all phonon channels by adjusting driver offsets, set baselines near -0.7. As seen yesterday, DIB2pB and DIB3pC show no pulses. Some ugly noise in many channels, particularly DIB3pD. Maybe we should try powercycling the DCRCs. |
| 1034 | In addition to the two channels not showing pulses, the channels that do show pulses look “peaky-er” than usual. This might just be paranoia, though. Power off DCRCs. Let fridge cool. Tower temp spikes to 62mK, then drops. |
| 1055 | Tower temp = 38.4mK. Repower DCRCs. Zap SQUIDs. |
| 1150 | Even after adjusting SQUID settings, DIB3 pC will not show pulses. Unable to get Test Signal to show up on DIB2 at all. Power off DCRCs and let them sit for longer. |
| 1245 | Tower temp = 37.5mK. Repower DCRCs. Zap SQUIDs. |
| 1310 | Adjusting Driver Offsets brings all channels back to life, but DIB2 pB & DIB3 pC still not showing pulses, and the rest show jagged pulses. Set up timing link to see if that helps. All pulses rail… |
| 1430 | All channels unrailed again. Same channels as before are showing no pulses, same jagged noise seen, pulses seem weak i.e. no strong well-shaped ones. |
| Apply -6V/+6V bias for a moment. More strong pulses seen, but they look “peaky” as mentioned above. They seem to have shorter than usual fall times. Could this be a helium films phenomenon? Maybe should warm up and pump out. | |
| 1435 | Close V6 to begin warm up procedure. Close turbo pump valve to monitor IVC pressure. |
| 1440 | Close V13B and turn off 3He pump. Turn on MC Heater to 1mW. Tower temp = 240mK. |
| 1445 | Tower 0.42 K and rising, G1 (condenser) 115 mbar and falling, IVC 7.4 nbar and steady |
| 1450 | Tower 0.62 K and rising, G1 (condenser) 75 mbar and falling, IVC 7.4 nbar and steady |
| 1455 | Tower 0.78 K and rising, G1 (condenser) 55 mbar and falling, IVC rising… suddenly Tower jumps to 3.2 K, IVC rises to 1200 nbar… |
| 1450 | Tower 3.5 K and flat, G1 (condenser) 50 mbar and flat, IVC 1600 nbar |
| 1500 | IVC pressure still 1600 nbar. G1 rising now, at 95 mbar. 1KPot also rising, 1.8 K / 20 mbar. Commence pumping out IVC with turbopump. |
| 1510 | Tower stuck at 3.7 K, G1 at 170 mbar and not falling. 1K Pot is falling, 1.7 K / 13 mbar. Tweak 1K Pot needle valve open a little in hopes of accelerating fridge cooling. |
| 1515 | Tower falling slowly, down to 3.2 K, G1 at 185 mbar and falling slowly. Pot peaked at 1.78 K / 40 mbar, has fallen to 1.68 K / 19 mbar |
| 1520 | Tower 3.0 K and falling, G1 (condenser) 160 mbar and falling. Turn off MC heater. |
| 1530 | Tower 2.5 K and flattening, G1 (condenser) 110 mbar and falling more slowly. 1K Pot is back in it's typical oscillatory mode. |
| 1535 | Turn on 3He pump and open V13b. G1/G2 settle at 145/135 mbar. Open V6 to 13.2%. G2 begins to rise. Begin opening V6 in steps. |
| 1610 | V6 = 13.8%, Still (P1) = 36 mbar, Tower = 1.5 K, G1/G2 = 320 mbar. |
| 1630 | V6 = 14.8%, Still (P1) = 2.2 mbar, Tower = 1.2 K, G1/G2 = 330 mbar. |
| 1645 | V6 = 15.0%, Still (P1) = 1.6 mbar, Tower = 0.78 K, G1/G2 = 330 mbar. Open V6 100%. |
| 1655 | Still (P1) = 160 μbar, Tower = 0.47 K and falling, G1/G2 = 360 mbar |
| 1725 | Still (P1) = 80 μbar, Tower = 49 mK and falling still, G1/G2 = 263/239 mbar. |
| 1730 | Fill LN2 cold trap full. |
| Commence overnight bake (12 hours). |