2020/11/02 (Monday)
- Lab in-person: Ruiren, later Matt
- Virtual partner: Matt, later Zach,Michael,Derek,Pramod
| Setup | Run 73. DIB 1/3/4 → Stripline 43/48/41 → pi-filters 1/2/3 → Cable 3/1/2 → nothing/nothing/accessory_interposer → HV_Conn 1/3/2 → HV 1/2 → DCRCX(4)/DCRC55(1)-master; DCRC33(2) → HV control. DCRCs on. Lead/poly shield erected (4 lead walls, 2 poly walls). |
|---|---|
| Status | Doing a partial warmup because I suspect helium films on the detector are making the phonon channels behave funny. Suspended circulation yesterday. In the lab today we'll stop the 1K Pot. Mixture is still in fridge, V6 closed, V3 open, 3He pump on. |
| 0800 | MB = 29.3% |
| 0900 | Tower = 1.34 K, slowly rising. G1(fridge) = 33.1 mbar. |
| 0900 | Ruiren temperature = 36.6 C |
|---|---|
| 1010 | Ruiren enters lab |
| 1015 | Close 1K Pot Needle Valve. Close 1K Pot Speedivalve. Close valve at 4He Pump. Switch 4He pump outlet from Recovery to Exhaust. |
| 1023 | Tower/MC/Coldplate = 1.37 K/1.36 K/2.51 K, Still = 2.48 K / 1000 mbar / 0 mW, G1/G2= 34/27 mbar, 1K Pot = 2.35 K and rising, P2 = 0.015 mbar. |
| 1023 | transfer lN2 into cold trap dewar |
| 1030 | Ruiren leaves lab |
| 1030 | Close V4a. Turn off 4He pump. |
| 1040 | Tower/1K Pot = 1.39/3.0 K |
| 1040 | Turn on MC/Still heaters to 20/30 mW. Tower temperature starts rising fast. |
| 1100 | Tower = 3.15 K. As it rose there was a bit of a flattening around 2.0 K, and another longer one with some wiggles around 2.5 K. Maybe these are associated with the lambda point, as the helium on the tower warmed from superfluid to ordinary liquid. |
| Another temperature kink at 3.5 K, no theory for that one. | |
| 1130 | Tower/1K Pot = 3.97/4.15 K. Tower temperature is flattening. |
| 1130 | Turn on DCRC1 LEDs with increased duty cycle: width/rate = 100/1000 us instead of standard 100/10000 us. Tower temperature rises more quickly. |
| 1135 | Tower = 4.13 K. It seems to have plateaued. |
| 1145 | G1 (fridge) = 906 mbar. Probably should let some into the dump soon. |
| 1145 | Turn off 3He pump. Fridge pressure falls a bit. |
| 1155 | G1(fridge) = 932 mbar. Open V4 for half a minute to let some mixture into dump. G1→800 mbar. This has a cooling effect, Tower 4.2→4.05 K |
| 1159 | Tower suddenly starts rising from 4.2 K |
| 1207 | 1K Pot suddenly starts rising from 4.5 K |
| 1214 | 1K Pot thermometer maxes out at 7K |
| 1230 | Tower = 7.5 K. Turn off LEDs. |
| 1230 | G1(fridge) = 975 mbar. Open V4 for half a minute to let some mixture into dump. G1→773 mbar. |
| 1235 | Turn off MC/Still heaters. |
| 1245 | Tower has settled to 6.84 K |
| 1315 | Tower flat at 6.5 K |
| 1420 | Matt enters lab |
| 1425 | Matt Fritts body temperature = 97.5 F |
| 1430 | Start 4He pump, open pump valve, switch pump outlet back to Recovery |
| 1440 | Start LHe transfer @ MB = 19.3% |
| 1445 | Tower/1KPot = 6.80/>7 K |
| 1445 | Turn off DAQ programs, Unplug power from DCRC1&4 |
| 1445 | Check pressure in 1K Pot by opening speedivalve (V4a closed): about 0.37 bar on mechanical gauge. 1K Pot temperature falls to 5.4 K |
| 1455 | Pump out 1K Pot in steps, alternating between speedivalve and V4a, opening briefly to keep pump inlet pressure low. 1K Pot → 3.6 K / 0.8 mbar. |
| 1500 | MC(H35)/Tower = 6.65/6.70 K |
| 1500 | Open 1K Pot needle valve → 10°. 1K Pot → 3.0 K / 7.5 mbar. Open 1K Pot needle valve → 20°. 1K Pot → 2.6 K / 14 mbar. |
| G1 (fridge) is dropping, → 390 mbar. Tower falling slowly, → 6.62 K | |
| 1505 | Open 1K Pot needle valve → 30°. 1K Pot → 2.4 K / 20 mbar. Oscillating. Tower temperature falling more quickly. |
| 1510 | Tower = 3.4 K and falling |
| 1513 | End LHe transfer @ MB = 91.2% |
| 1525 | Tower = 2.35 K and falling. 1K Pot = 1.54 K / 9.0 mbar. Open 1K Pot needle valve → 40°. 1K Pot → 1.54 K / 9.0 mbar, no change |
| 1535 | Open 1K Pot needle valve → 50°. 1K Pot → 1.53 K / 8.5 mbar. Hmm, hope it isn't clogged. |
| 1535 | Tower = 2.17 K. G1(fridge) = 65 mbar. Turn on 3He pump. |
| 1545 | G1(fridge) = 64 mbar. Open V9. This lets the mixture from the dump into the fridge through cold LN2 Trap 1. G1(fridge)→166 mbar and rising. Tower temperature rises, 2.15→2.22 K. 1K Pot rises → 1.73 K / 190 mbar. |
| G1(fridge) peaked at 275 mbar then started falling. 1K Pot peaked at 200 mbar then started falling. | |
| 1550 | Plug in DCRC1&4. |
| 1550 | Start DAQ programs and zap SQUIDs |
| 1555 | Matt leaves lab |
| 1630 | 1K Pot = 50° / 1.65 K / 31±1 mbar. Tower = 2.00 K, G1 (fridge) = 54.1 mbar. |
| 1645 | Tower = 1.90 K, G1 (fridge) = 51.4 mbar. |
| 1725 | Tower = 1.85 K, G1 (fridge) = 46.6 mbar. |
| 1725 | Close V3 and V9, leaving 40 mbar (G2) in the dump. |
| 1725 | Start circulation through Trap 1. V6 → 12.8%. Condenser peaks at 243 mbar. (G2 peaks higher than G1.) Tower drops to 1.66 K. |
| 1735 | V6 → 13.2%. Condenser peaks at 297 mbar. Tower → 1.56 K |
| 1750 | V6 → 13.4%. Condenser peaks at 330 mbar. Tower → 1.56 K. Still → 700 mbar |
| 1805 | V6 → 13.6%. Condenser peaks at 414 mbar. Tower → 1.52 K. Still → 50 mbar. |
| 1825 | V6 → 14.0%. Condenser peaks at 514 mbar. Tower → 1.39 K. Still → 8.0 mbar. |
| 1835 | V6 → 14.4%. Condenser peaks at 504 mbar. Tower → 1.25 K. Still → 3.6 mbar. |
| 1845 | V6 → 15.0%. Condenser peaks at 436 mbar. Tower → 1.06 K. Still → 1.5 mbar. |
| There were some small wiggles as the Tower cooled below the 1.2 K Al transition temperature but mostly it seems to have plowed through it. | |
| 1855 | V6 → 100.%. Condenser peaks at 458 mbar. Tower → 0.70 K. Still → 0.22 mbar. |
| 1940 | Tower = 99 mK, Still = 0.130 mbar, G1/G2 = 331/305 mbar. |
| 1940 | Open V14 to let the remaining mix out of the dump and into circulation. P1(Still) peaks at 55 mbar then falls again. Tower peaks at 99 mK. Condenser peaks at 421 mbar. |
| 2030 | Tower = 63.3 mK, Still = 0.380 mbar, G1/G2 = 310/285 mbar. |
| 2030 | Close V14 |