2016/07/22 (Friday)
| Setup: iZIP mode, DIB1/2/3 → cables → 3.2 MHz filters → DCRC55(1)/33(2)/50(3) | |
| DCRCs on overnight taking bg data. Note: fridge was cooled below Al transition with mu-metal shield at standard height. Tower temperature quite stable between flashes. | |
| 0735 | Tower/MC/Coldplate = 34.7/31.5/157 mK, Still = 1.39 K / 0.15 mbar, G1/G2 = 165/155 mbar, 1K Pot = 1.44 K / 2.0 mbar, MB = 39.4% |
| 0740 | Close V6 to begin another warmup. Close V13a and turn off 3He pump. |
| 0745 | Fill LN2 cold trap bath Open 1K Pot needle valve a few degrees more Apply 1 mW to MC heater |
| 0750 | Lower mu-metal shield 45.9 cm below standard position (partially into pit) |
| 0755 | Still pressure (P1) reads “1000” mbar. Open V3. G1(condenser) falls from 35 to 20 mbar. |
| 0800 | Tower/MC/Coldplate = 0.83/0.96/0.84 K. 1K Pot = 1.62 K / 11 mbar |
| 0820 | Tower = 1.44, then starts to shoot up, to 2.9 K; G1 rising too Tower/MC/Coldplate/Still = 3.1/2.3/2.4/2.8 K ,G1 = 50 mbar and climbing |
| 0825 | Tower = 3.3 K, G1 = 130 mbar and still climbing. Turn off MC heater. G1 settles at 150 mbar. Turn on 3He pump, open V13a, close V3. |
| 0830 | G1/G2 = 145/130 mbar. Begin opening V6. At V6 = 12.8% some increase in pressure is seen. |
| 0835 | G1/G2 = 150/135 mbar and flat, 1K Pot = 1.68 K / 11 mbar. Open V6 to 13.4% to see another pressure increase (maybe the increase seen at 12.8% was spurious) |
| 0845 | 1KPot empties, 1.72K/20mbar → 2.5K/4 mbar. Tweak open needle valve, falls back to 1.8 K |
| 0850 | G1/G2 = 445/410 mbar and falling, 1K Pot = 1.80 K / 60 mbar. Open V6 to 13.6%. G1/G2 → 800 mbar, that's pretty high, and pot seems to be straining (2.1 K) |
| 0855 | Tower/MC/Coldplate/Still = 3.4/3.8/3.6/3.4 K Stop circulation. Close V6, then V13a. |
| 0900 | 1K Pot = 2.4 K and climbing, 20 mbar. Tweak it open, temperature falls to 1.8 K again |
| Yesterday when we couldn't get the still started we let the pot cool it to 2.2 K. Let's try to make that happen again. | |
| 0905 | Condenser (G1) has fallen to 260 mbar. Open V3 to equalize still and condenser. |
| 0915 | Still = 3.2 K, G1 = 215 mbar and flat, 1K Pot = 1.73 K / 20 mbar. Doesn't seem to be cooling the still much. IVC = 160 nbar. Is the temperature spike occurring from a boiloff of He in the IVC? Pump on IVC again with turbo. |
| 0920 | Still, G1, and 1K Pot have all started falling. Yep, gas in the IVC was screwing up the cooldown. |
| 0925 | Still = 2.5 K, G1 = 125 mbar, 1K Pot = 1.59 K / 7 mbar. All are falling. Turbo (pumping IVC) = 1.9 nbar |
| 0935 | Still = 2.1 K, G1 = 70 mbar, 1K Pot = 1.50 K / 4 mbar, leveling off. Turbo (pumping IVC) = 1.2 nbar |
| 0940 | Open V13a in spurts to let mix from dump into fridge, 1K Pot temperature spikes in response. Accidentally opened V13b at one point, so some mix was let into Trap 2. Will need to pump this back in at some point. |
| 0945 | Still = 1.9 K, G1 = 60 mbar, 1K Pot = 1.48 K / 3.4 mbar. Tweak needle valve. Close V3. Close pump to turbo, stop pumping out IVC. IVC = 7.4 nbar. |
| 0950 | G1/G2 = 60/50 mbar. Open V6 to 13.2%, G1/G2 start to rise. |
| 0955 | G1/G2 = 80/70 mbar. Open V6 to 13.5%. |
| –delay for meeting– | |
| 1100 | G1/G2 = 114/105 mbar and falling slowly. P1 has actually fallen into readable range after the long delay. 1KPot = 1.43 K / 1.7 mbar, tweak it open more. Open V6 to 13.8%. |
| 1120 | G1/G2=214/198 mbar and stable. P1=6.5 mbar, and 1K Pot = 1.54 K/ 5.0 mbar. Open V6 to 14.0%. |
| 1130 | G1/G2=228/209 mbar and dropping. P1=2.4 mbar, and 1K Pot = 1.51 K/ 4.0 mbar. Open V6 to 14.6%. |
| 1133 | G1/G2=240/222 mbar and dropping again. P1=1.2 mbar and 1K Pot = 1.49 K / 3.8 mbar. Open V6 (cautiously) all the way. G1/G2 rise to 260/242 mbar and stabilize as P1 drops to 0.18 mbar. |
| 1145 | MC/Tower=416/440 mK and steadily dropping. |
| 1150 | Attempted crude repairs of damaged LN2 cold trap. Tried forcing dewar inner faces back into place using wood blocks, hammers, and crow bar. |
| 1205 | Tower = 73.2 mK, Still = 0.08 mbar, G1/G2 = 185/170 mbar and falling, 1K Pot = 1.45 K / 2.4 mbar |
|---|---|
| 1225 | Tower = 52.2 mK, Still = 0.08 mbar, G1/G2 = 170/160 mbar, 1K Pot = 1.44 K / 2.2 mbar. Tweak needle valve open a few more degrees. This made G1/G2 go up. |
| 1240 | Tower = 45.2 mK, Still = 0.09 mbar, G1/G2 = 205/190 mbar, 1K Pot = 1.65 K / 17 mbar. |
| 1250 | Tower hanging at 40 mK, probably because we don't have all the mix in there - there's some in the dump and some in Trap 2. Open V14 briefly to let some mix from dump in, G1/G2 go up to 270 mbar then fall again |
| 1255 | Open V6 until G2 reaches 500 mbar then close again. Tower rises to 0.3 K then falls again. |
| 1305 | Tower temperature starting to stabilize at 98 mK, G1/G2 = 283/262 mbar. Open V14. |
| 1307 | After leaving V14 open, P1 has dipped below 1000 mbar and is rapidly decreasing while G1/G2 = 387/363 mbar. These pressures will not get above 500 mbar, so we can leave V14 open until all the mixture is out of the dump (P1 < 1 mbar). Currently tower temperature is at 149 mK and beginning to drop. |
| 1330 | G1/G2= 201/186 mbar, P1=0.80 mbar, Tower = 48 mK. Close V14 to isolate dump. Reminder: there is still some mixture that must be pumped out of cold trap 2 from earlier. |
| 1400 | Tower = 35.6 mK, Still = 0.085 mbar, G1/G2 = 170/160 mbar, 1K Pot = 1.45 K / 2.2 mbar. |
| 1410 | Get mixture out of Trap 2: Close V1 and V12a+speedi (stops return to condenser temporarily), open V12b+speedi and V3 (pumps Trap 2 to dump, and also increases still pressure, similar to opening V14 to get mix out of dump). Tower spikes to 3K(!) then fall quickly below 0.5 K. G2 building up but not too badly, to 320 mbar. P1 falls to 0.4 mbar after a few minutes. |
| 1415 | Close V12b+speedi and V3. Open V1. Open V12a speedivalve only, let pressure slowly out of trap into condenser. G1/G2 stabilize at 255/315 mbar. Open V12a 100%. |
| 1435 | Tower = 52.4 mK and falling, Still = 0.120 mbar, G1/G2 = 225/210 mbar, 1K Pot = 1.60 K / 8.5 mbar. |
| Tower has been cooled below Al transition with mu-metal shield 45.9 cm below standard position | |
| 1445 | Raise mu-metal shield to standard position |
| 1450 | Commence LHe transfer (28.9%). |
| 1515 | Tower = 44.9 mK, Still = 0.095 mbar, G1/G2 = 175/165 mbar, 1K Pot = 1.44 K / 2.8 mbar. |
| 1535 | Check phonons, readjust driver offsets. All look OK. |
| 1544 | Cease LHe transfer. (91.8%) |
| 1550 | Release pressure from main bath (5 min after fill). |
| 1555 | Tower/MC = 43.2/30.6 mK, Still = 0.090 mbar, G1/G2 = 170/160 mbar, 1K Pot = 1.42 K / 2.2 mbar. |
| why is Tower elevated now, compared to before we let the Trap 2 mix back in? The Tower-MC difference is a lot higher, MC is as low as it was this morning. | |
| 1620 | Tower/MC/Coldplate = 42.7/30.2/168 mK, Still = 1.45 K / 0.090 mbar, G1/G2 = 165/160 mbar, 1K Pot = 1.44 K / 2.6 mbar. Open needle valve a few degrees more. |
| 1625 | Release pressure from main bath (40 min after fill). |
| 1635 | MC = 41.8 mK, seems to be cooling slowly. |
| 1635 | Start 15 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. |
| 1639 | Tower temp went a little higher during the flash, to 260mK. |
| 1640 | Filled LN2 cold trap and top off HPGe dewar. |
| 1711 | 1K Pot at 1.46 K / 3.4 mbar. Open needle valve a bit and give time to settle. |
| 1722 | After a few minutes 1K Pot has reached to 1.74 K / 85 mbar and the P2 pressure is still dropping slowly. Hopefully this will last through till tomorrow. |