2018/04/16 (Monday)
| Status: Tower installed, IVC sealed, turbo pump on IVC over the weekend. Mixture cleaned several times. Cryostat vacuum jacket pumped out. | |
| 0955 | Turbo = 14 nbar, IVC = 190 nbar with pump valved out |
| 1000 | Repeat electrical check on DIB3. On Friday it was seen that some pins on the SQUET seemed intermittently bad, would read nearly open. Only one phonon-related channel is a problem now: SQUID B reads 0.7 MΩ. That's not a Side1 channel so shouldn't be a problem. On DIB3 only pC is Side1. |
| 1115 | Put leak detector on IVC. Background = 3.6 pbarL/s. |
| 1210 | Start cryocleaning mixture through cold LN2 Trap 2, V6 = 12.9% |
| 1240 | Increase V6→ 13.2% to restart flow |
| 1305 | Increase V6→ 13.3% to speed up flow |
| 1330 | Leak check IVC. At some places near the elbow of the stripline tube and the nearby o-ring connections the signal rose as high as 10 pbarL/s. No leaks at the indium joints. |
| 1340 | Raise main bath. |
| 1345 | Stop cryocleaning. Trap 2, 95 minutes. Final G2 pressure = 645 mbar. |
| 1410 | Start cryocleaning mixture through cold LN2 Trap 1, V6 = 13.0% |
| 1420 | Increase V6→ 13.2% to restart flow |
| 1510 | Stop cryocleaning. Trap 1, 60 minutes. Final G2 pressure = 670 mbar. |
| 1520 | Check pressure in warm LN2 Trap 2: 4.0 mbar. Pump out with scroll pump. |
| Cryocleaning log | |||
|---|---|---|---|
| date | trap | duration (minutes) | contaminants removed (mbar) |
| Apr 6 | 1 | 70 | 9.5 |
| Apr 6 | 2 | 70 | 6.6 |
| Apr 6 | 1 | 70 | 11.0 |
| Apr 6-7 | 2 | overnight, no circ, dump exposed to trap | 12.8 |
| Apr 7-9 | 1 | overnight, no circ, pump exposed to trap | 6.8 |
| Apr 9 | 2 | 70 | 8.9 |
| Apr 9 | 1 | 60 | 9.0 |
| Apr 10 | 2 | 90 | 10.5 |
| Apr 10 | 1 | 70 | 8.5 |
| Apr 10 | 2 | 75 | 6.6 |
| Apr 10 | 1 | 70 | 1.9 |
| Apr 11 | 2 | 75 | 2.7 |
| Apr 11 | 1 | 75 | 14.4 |
| Apr 11 | 2 | 70 | 4.5 |
| Apr 11 | 1 | 70 | 6.4 |
| Apr 12 | 2 | 70 | 4.7 |
| Apr 12 | 1 | 135 | 3.3 |
| Apr 16 | 2 | 95 | 4.0 |
| Apr 16 | 1 | 60 | |
| 1415 | Let 5.4 mbar He exchange gas into IVC |
|---|---|
| 1420 | Check pressure in 1K Pot: P2 = 24 mbar. Pump out with scroll pump. |
| 1440 | Pump out main bath down to <1 mbar |
| 1450 | Pressurize main bath with He to 310 mbar above 1atm on G3. |
| 1530 | Check fridge pressures: LHe trap/Condenser/Still = 5.4/1.0/0.22 mbar. Pump out with scroll pump. |
| 1540 | Let mixture from dump into fridge through cold LN2 Trap 2. 3He pump off, V9, V13b, V12b+speedi, V3, V1, condenser & still valves all open |
| 1545 | Begin transferring LN2 |
| 1545 | MC(Cernox) = 297.1 K, Sorb = >249 K (max), IVC = 5.4 mbar, G1 (fridge) = 612 mbar, Level resistor = 0.985 kΩ. |
| 1550 | MC(Cernox) = 297.2 K, Sorb = >249 K (max), IVC = 5.4 mbar, G1 (fridge) = 611 mbar, Level resistor = 1.045 kΩ. |
| 1600 | MC(Cernox) = 294.0 K, Sorb = >249 K (max), IVC = 4.6 mbar, G1 (fridge) = 610 mbar, Level resistor = 1.081 kΩ. |
| 1610 | MC(Cernox) = 281.9 K, Sorb = >249 K (max), IVC = 4.0 mbar, G1 (fridge) = 609 mbar, Level resistor = 1.135 kΩ. |
| 1620 | MC(Cernox) = 262.2 K, Sorb = >249 K (max), IVC = 3.0 mbar, G1 (fridge) = 607 mbar, Level resistor = 1.210 kΩ. |
| 1630 | MC(Cernox) = 238.2 K, Sorb = >249 K (max), IVC = 2.5 mbar, G1 (fridge) = 605 mbar, Level resistor = 1.292 kΩ. |
| 1640 | MC(Cernox) = 211.1 K, Sorb = >249 K (max), IVC = 2.5 mbar, G1 (fridge) = 603 mbar, Level resistor = 1.339 kΩ. |
| 1650 | MC(Cernox) = 187.4 K, Sorb = 224 K, IVC = 2.2 mbar, G1 (fridge) = 601 mbar, Level resistor = 1.339 kΩ (flat). |
| 1700 | MC(Cernox) = 170.1 K, Sorb = 191 K, IVC = 2.2 mbar, G1 (fridge) = 600 mbar. |
| 1705 | Stop LN2 transfer |
| 1710 | MC(Cernox) = 156.8 K, Sorb = 168 K, IVC = 1.9 mbar, G1 (fridge) = 598 mbar. |