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2023/02/01 (Wednesday)

Previous Day

  • Lab in-personnel: Himangshu, Zach
Status Run 77 preparation
Setup Fridge closed, pumping on IVC, preparing for cooldown
1402 Refilled LN2 Cold trap 1
Flow mixture through fridge:
  1. Open V9, V13a, wait a min, V12a+speedivalve, condenser speedivalve, still gate, V1, wait a min, V3, let things settle.
  2. Turn on 3He pump, after a min, open V6 to 12% and close V3.
  3. If P1 does not fall low enough (about less than 1 mbar) Open V6 more until it does (usually to 12.6%)
1422 Open V6 to 12.4%, P1 falls to 0.34 mbar
1430 Try closing V12a+speedivalve. G1 falls as it should, showing we have throughput. Falls at 11 mbar/min . Open V12a+speedivalve again.
1435 Currently 6.3 mbar He exchange gas in the IVC
1435 MC(Cernox) = 296.4 K, Sorb = >249 K (max), IVC = 6.3 mbar, G2/G1/P1 (circulation) = 651/723/0.36 mbar, Level resistor = 0.983 kΩ.
1445 Inserted LN2 transfer stick, connected to the LN2 dewar with a hose, inserted the level resistor, disconnected the helium recovery line.

1447 Begin LN2 transfer
1500 MC(Cernox) = 296.0 K, Sorb = >249 K (max), IVC = 6.3 mbar, G2/G1/P1 (circulation) = 654/726/0.60 mbar, Level resistor = 0.989 kΩ.
1500 Close V12a speedivalve for 2 minutes to assess throughput. (Condenser pressure G1 should fall.) G1 falls at 11.7 mbar/min. Open V12a speedivalve again.
1515 MC(Cernox) = 285.18 K, Sorb = >249 K (max), IVC = 6.3 mbar, G2/G1/P1 (circulation) = 655/726/1.000 mbar, Level resistor = 1.002 kΩ.
1532 MC(Cernox) = 260.7 K, Sorb = >249 K (max), IVC = 3.4 mbar, G2/G1/P1 (circulation) = 657/726/1.90 mbar, Level resistor = 1.026 kΩ.
1545 MC(Cernox) = 232 K, Sorb = >249 K (max), IVC = 3.0 mbar, G2/G1/P1 (circulation) = 657/726/3.2 mbar, Level resistor = 1.069 kΩ.
1545 Close V12a speedivalve for 2 minutes to assess throughput. (Condenser pressure G1 should fall.) G1 falls at 17.5 mbar/min. Open V12a speedivalve again.
1600 MC(Cernox) = 188 K, Sorb = >249 K (max), IVC = 2.5 mbar, G2/G1/P1 (circulation) = 658/726/6.5 mbar, Level resistor = 1.145 kΩ.
1617 MC(Cernox) = 164 K, Sorb = >249 K (max), IVC = 2.2 mbar, G2/G1/P1 (circulation) = 658/724/20 mbar, Level resistor = 1.204 kΩ.
1631 MC(Cernox) = 147 K, Sorb = 232 K, IVC = 2.2 mbar, G2/G1/P1 (circulation) = 657/723/20 mbar, Level resistor = 1.245 kΩ.
1646 MC(Cernox) = 131 K, Sorb = 194 K, IVC = 2.2 mbar, G2/G1/P1 (circulation) = 656/721/maxout mbar, Level resistor = 1.280 kΩ.
1650 Close V12a speedivalve for 2 minutes to assess throughput. (Condenser pressure G1 should fall.) G1 falls at 44.5 mbar/min. Open V12a speedivalve again.
1700 MC(Cernox) = 120 K, Sorb = 166 K, IVC = 1.9 mbar, G2/G1/P1 (circulation) = 655/719/maxout mbar, Level resistor = 1.302 kΩ.
1715 MC(Cernox) = 112 K, Sorb = 149 K, IVC = 1.9 mbar, G2/G1/P1 (circulation) = 653/717/maxout mbar, Level resistor = 1.312 kΩ.
1743 MC(Cernox) = 98 K, Sorb = 130 K, IVC = 1.6 mbar, G2/G1/P1 (circulation) = 649/713/maxout mbar, Level resistor = 1.327 kΩ.
1745 Stop LN2 transfer. Close LN2 Dewar valve. Pull out Level Resistor and put stopper in port. Put ping-pong ball on MB exhaust port.
1745 Close V6 and turn off 3He pump.

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