2016/07/21 (Thursday)
| Setup: iZIP mode, DIB1/2/3 → cables → 3.2 MHz filters → DCRC55(1)/33(2)/50(3) | |
| DCRCs on overnight taking Ba data. Note: fridge was cooled below Al transition with mu-metal shield lowered 32.3 cm. | |
| Fridge failure: 1K Pot ran dry at 4:06 am, from 1.4K/1.4mbar → 1.7K/1.0mbar. It was already down to 1.5 mbar by 9am. By 7:00 Tower had risen to 0.4 K, G1/G2 circulation pressures were around 900 mbar, P1 circulation pressure at 0.5 mbar. 1K Pot up to 4.7 K. | |
| 0725 | close V6. G1/G2 fall to 500 mbar, 1K Pot temperature falls to 3 K, Tower rises to 3.6 K. |
| 0730 | Close V13a with G2 at 658 mbar - this much mixture now isolated in pump. Turn off 3He pump. |
| 0735 | G1 falls to 400 mbar then starts to rise again. Open 1K Pot needle valve a few degrees. |
| 0740 | Lower mu-metal shield to 37.8 cm below standard position |
| 0740 | 1K Pot = 2.32 K / 8 mbar, falling slowly. G1 = 480 mbar, was rising, now flat. Tower = 3.9 K and flat. |
| 0745 | Fill LN2 cold trap bath |
| 0750 | 1K Pot is hanging around 2.35 K. Can we try starting circulation? |
| 0750 | Turn on 3He pump. Open V13a. G1/G2 → 575/530 mbar. 1K Pot rises a little, → 2.64 K / 6 mbar. Pressure lowish: open needle valve a little more. |
| 0800 | Open V6 to 13.4%. G1/G2 were at 480/520 mbar, now rising. Peak at 560/510 mbar, now falling. Still = 4.5 K |
| 0802 | Open V6 to 13.6%. G1/G2 rise too quickly. Close V6 before G1 reaches 950 mbar. Pressures falling. |
| 0805 | Open V3 to get pressures low (letting mixture expand into still pumping line). Pressures stabilize at G1/G2 = 535/495 mbar. Close V3 again. |
| 0810 | Open V6 to 13.4% again. But pressures go too high. Close V6 again and open V3. |
| 0815 | Crank 1K pot needle valve open more, finally it falls below 2 K. 1K Pot = 1.91 K / 45 mbar. G1/G2 start to fall. Let it settle. |
| 0817 | Main Bath (MB) = 72.1%. Good boiloff rate, nice and slow. Pattern of releasing pressure yesterday (5min, then 30min, then 60min after fill) worked. |
| 0820 | G1/G2 = 395/360 mbar, still falling. 1K Pot = 1.86 K / 20 mbar. |
| 0830 | G1/G2 = 380/345 mbar. Try circulating again. Tweak 1K Pot needle valve open more. Open V6 to 13.2%, G1/G2 go up to 440/410 mbar then fall again. |
| 0840 | G1/G2 = 320/295 mbar, falling. Open V6 to 13.4%. 1K Pot rise above 2 K so tweak it open again, drops back to 1.8 K. G1/G2 peak at 510/470 mbar then fall again. Still = 3.8 K |
| 0855 | G1/G2 = 375/350 mbar, falling. Open V6 to 13.6%. 1K Pot has slowly risen above 2 K so tweak it open again, drops back to 1.8 K. G2 looked looked like it would stop at 710 mbar but then rose again because pot high again, annoying. Tweak pot again. G1/G2 peak at 750/700 mbar then |
| 0905 | 1K Pot climbs above 2K, tweak needle valve again. Each time this happens, opening the needle valve more causes the pot temperature to fall. Pressure goes up but then falls off, and another temperature increase happens. The pressure at which this occurs keeps getting higher: 10, 15, 15, 30, 40 mbar. Troubling. |
| 0910 | Still = 3.6 K. G1/G2 = 735/685 mbar, falling slowly. Too high to try opening V6 more. Open V4 for a minute to release condenser pressure into dump. |
| 0915 | G1/G2 = 515/480 mbar, climbing slowly. Open V6 to 13.7%. G1/G2 rise slowly, to 705/655 mbar in 5 minutes. 1K Pot needs tweaking again, at pressure of 30 mbar. |
| 0925 | G1/G2 flat at 720/670 mbar. Open V4 again to release some pressure. G1 falls to 420 mbar while V4 open, that is presumably the dump pressure. Close V4, pressures rise somewhat. |
| 0930 | G1/G2 = 595/560 mbar. Open V6 to 13.8%. 1K pot needs another tweak at 30 mbar. G1/G2 rise to 760/710 mbar. |
| 0935 | Open V4 again to release pressure, G1 fall to 460 mbar, close V4. |
| 0940 | G1/G2 = 645/605 mbar. Open V6 to 13.9%. Was hoping that the still pressure would come down, no luck. Everything is too warm. |
| 0945 | Another 1K Pot tweak, at 30 mbar again |
| 0950 | OK this isn't working. Need to investigate the pot. Stop circulation: close V6 & V13a, open V3. 1K Pot surge then settles at 1.74 K / 26 mbar. |
| 0955 | Tower/MC/Still = 3.4/3.3/4.8 K. At least Tower has gone down. Should let 1K Pot try to cool these. (Why is Still so high??) |
| 1015 | Tower/MC/Still = 3.4/3.4/4.1 K. OK, maybe Still is cooling slowly. |
| 1020 | Noticed IVC = 220 nbar. Was 12 nbar on the 13th after pumping out after the first LHe transfer. Try pumping with turbo. |
| 1025 | Open V13a to let mix from pump into fridge. Surge in 1K Pot temperature. Pot had been pretty stable for a while, down to about 1.7 K, pressure had decreased to 15 mbar. |
| 1030 | 1K Pot = 1.75 K / 9.5 mbar, tweak needle valve again. After this Still temperature starts falling, and fridge pressure too, that's encouraging. |
| 1045 | Tower/MC/Still = 2.4/2.7/2.3 K. 1K Pot and Still and Fridge pressures were all decreasing together, then flattened. 1K Pot = 1.58 K / 7 mbar, kinda low, should it be tweaked again? |
| 1050 | Open V9 to let dump mixture into fridge. 1K Pot temperature and pressure surge. |
| 1100 | Tower/MC/Still = 2.25/2.47/2.21 K, G1/G2 = 85/100 mbar, 1K Pot = 1.62 K / 12 mbar. Pot and G1/G2 have been decreasing for the last 10 minutes. |
| 1105 | Close V9, leaving 76 mbar in dump. Close V3. Begin opening V6. At 13.0%, G2 starts to increase. 1KPot down to 1.54 K / 5 mbar, tweak open more. |
| 1110 | IVC pumping pressure down to 1.2 nbar. Close valve to pump. IVC = 7.4 nbar. |
| 1115 | G1/G2 = 80/75 mbar and falling. 1K Pot = 1.71 K / 40 mbar. Open V6 to 13.2%. |
| 1120 | Tower/MC/Still = 2.16/2.41/2.19 K |
| 1130 | G1/G2 = 110/105 mbar and flattish. 1K Pot = 1.68 K / 24 mbar. Open V6 to 13.4%. |
| 1140 | G1/G2 = 205/190 mbar and flattish. 1K Pot = 1.66 K / 19 mbar. Open V6 to 13.6%. |
| 1150 | G1/G2 = 300/280 mbar and flattish. 1K Pot = 1.64 K / 15 mbar. Open V6 to 13.8%. |
| 1155 | G1/G2 = 365/342 mbar and flattish. 1K Pot = 1.63 K / 13 mbar. Open V6 to 14.0%. P1 begins dropping. |
| 1200 | Tower/MC/Still = 1.26/1.43/1.67 K |
| 1205 | G1/G2 = 370/345 mbar and falling, P1 = 7 mbar. 1K Pot = 1.62 K / 12 mbar. Open V6 to 14.2%. |
| 1210 | G1/G2 = 305/285 mbar and falling, P1 = 2.8 mbar. 1K Pot = 1.61 K / 11 mbar. Open V6 to 100%. |
| 1215 | Tower/MC/Coldplate = 1.11/1.03/0.83 K, Still = 1.31 K / 0.22 mbar, G1/G2 = 325/305 mbar, 1K Pot = 1.61 K / 9.5 mbar |
| 1230 | Tower/MC/Coldplate = 87/70/174 mK, Still = 1.38 K / 0.15 mbar, G1/G2 = 275/255 mbar, 1K Pot = 1.61 K / 9.5 mbar |
| 1300 | Tower/MC/Coldplate = 40.4/30.4/157 mK, Still = 1.39 K / 0.11 mbar, G1/G2 = 200/190 mbar, 1K Pot = 1.57 K / 6.5 mbar |
| at some point, mu-metal shield was raised to its standard position | |
| 1315 | Tower is at 37.4mK. All pulses look good after messing with Driver Offsets. Start a 30min background series at -4/+4 V with FG=5/2/5, OG=8/3/8, with 1000 initial randoms, 1000 ending randoms, with 30s flash and 25 minute cooldown between series. Trigger on DIB1 phA with threshold of 30ADC bins, with 150 us pileup cut window. |
| 1415 | Series finished. Close V6 to commence warm up procedure. |
| 1420 | V6 is closed. Close V13A and turn off He3 pump. Turn MC Heater to 1mW. |
| 1445 | We've skipped the step of opening V3, doesn't really seem necessary. Tower = 1.1 K & rising, G1 = 25 mbar and falling slowly, P1 = “1000” |
| 1454 | Tower/MC/Coldplate = 1.38/1.52/1.00 K |
| 1510 | Tower/MC/Coldplate = 1.61/1.78/1.51 K. It may be behaving differently with V3 closed. Last two times, Tower jumped up at around 40 minutes after beginning heating. We are at the 50 minute mark. |
| 1525 | Tower/MC/Coldplate = 1.79/1.96/2.07 K |
| 1530 | 1K Pot = 1.50 K / 4.5 mbar, tweak open before cooling |
| 1535 | Turn on He3 pump, and open V13A. G1/G2 rise to 89/87 mbar, then settle downward. |
| 1540 | Open V6 to 13.2% and G1/G2 begin rising. |
| 1555 | G1/G2 = 80/76 mbar and flattish. 1K Pot = 1.61 K / 9.5 mbar. Open V6 to 13.4%. |
| 1610 | G1/G2 = 113/107 mbar and flattish. 1K Pot = 1.59 K / 8.0 mbar. Open V6 to 13.7%. |
| 1625 | G1/G2 = 299/281 mbar and flattish. 1K Pot = 1.56 K / 6.0 mbar. Open V6 to 13.9% and P1 starts dropping. |
| 1630 | Filled HPGe dewar |
| 1635 | G1/G2 = 383/359 mbar and flattish. 1K Pot = 1.56 K / 6.0 mbar. Open V6 to 14.1% and P1 keeps dropping. |
| 1640 | G1/G2 = 445/416 mbar and flattish. 1K Pot = 1.57 K / 6.5 mbar. Open V6 to 14.3%. |
| 1642 | Not much change. Open V6 to 14.5%, then 14.9%, then all the way. |
| 1657 | 1K Pot = 1.48 K / 4.0 mbar. Tweak open. Tower temperature at 991mK and dropping. |
| 1720 | G1/G2 = 348/326 mbar. 1K Pot = 1.69 K / 32 mbar. The MC Heater was still on, which was keeping the Tower at ~700mK. Turning it off dramatically increases cooling rate. |
| 1721 | Fill LN2 cold trap full. |
| 1755 | Tower temperature at 37.4 mK. 1K Pot at 18mbar, so tweak it open so we're good for overnight. |
| Cooled below 1.2 K Al transition with mu-metal shield in standard position | |
| 1800 | Check phonon channels. Adjusting the Driver Offsets brings all channels alive. |
| 1810 | Start 12 hours of 30min background series at -4/+4 V with FG=5/2/5, OG=8/3/8, with 1000 initial randoms, 1000 ending randoms, with 30s flash and 25 minute cooldown between series. Trigger on DIB1 phA with threshold of 30ADC bins, with 150 us pileup cut window. |