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2024/02/12 (Monday)

Previous Day

  • Lab in-personnel: Himangshu
Status Did a 10K pumpout to see if we can lower down the G1/G2 pressures. Begin another cooldown but couldn't complete as G1/G2 pressure increased linearly
1600 Fill LN2 cold trap dewar
Doing a throughput test to see if we need to change LN2 cold trap 1
1602 Pump mixture to dump. Start 3He pump. Close V13a, open V3 (V9 already open), open V6 more in steps up to 30%
1630 G1 = 0.4 mbar, P1 = 0.060 mbar. Stop pumping mixture to dump. Close V12a+speedivalve, close V1, close V3, close V6
1632 V6 is fully closed, close V9, leaving 550.3 mbar in the dump. Leave 3He pump on.
Throughput test procedure, Cold Trap 1:
  1. All mixture in dump, LN2 trap 1 cold, condenser & still valves open (3He pump on - optional)
  2. Open V9, V13a, V12a+speedivalve, V3. Wait for G1 to be close to G2 (within 100 mbar).
  3. Close V12a+speedivalve and V3, immediately open V1
  4. monitor G1
1638 Perform mixture throughput test at MC = 3.1 K using above procedure with 3He pump on. Let G1 rise to 568 mbar before Step 3, then it falls to 4 mbar, then rises. Throughput = 0 mbar/min.
1640 Open mixture to both sides of the fridge (V3) and cold LN2 Trap 1 (V12a+speedivalve).
1645 Change over to Cold Trap 2 now.
1646 Pump mixture to dump. Start 3He pump. Close V13a, open V3 (V9 already open), open V6 more in steps up to 30%
1705 G1 = 0.4 mbar, P1 = 0.1 mbar. Stop pumping mixture to dump. Close V12a+speedivalve, close V1, close V3, close V6
1707 V6 is fully closed, close V9, leaving 580.7 mbar in the dump. Leave 3He pump on.
1708 Pump out LN2 Cold Trap 2 first.
1730 Doing a throughput test to see if we can use LN2 cold trap 2
Throughput test procedure, Cold Trap 2:
  1. All mixture in dump, LN2 trap 2 cold, condenser & still valves open (3He pump on - optional)
  2. Open V9, V13b, V12b+speedivalve, V3. Wait for G1 to be close to G2 (within 100 mbar).
  3. Close V12b+speedivalve and V3, immediately open V1
  4. monitor G1
1638 Perform mixture throughput test at MC = 3.1 K using above procedure with 3He pump on. Let G1 rise to 568 mbar before Step 3, then it falls to 4 mbar, then rises. Throughput = 0 mbar/min.
1640 Open mixture to both sides of the fridge (V3) and cold LN2 Trap 2 (V12b+speedivalve).