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2019/11/04 (Monday)

Previous Day

Status: Replaced bottom IVC seal Friday. IVC pumped over the weekend. Cryostat vacuum jacket is pumped out. Working toward 2nd attempt at Run 71 cooldown.
0915 Turbo on IVC = 19 nbar. IVC = 540 nbar with turbo valved out for a few minutes
0915 Jiajin is unresponsive. Try turning it off and on again.
0920 Pump out both warm LN2 Traps and pump out fridge with scroll pump (all of these were just a little above minimum after sitting over the weekend). Put traps in bath and fill with LN2.
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.
  3. Close V13a+speedivalve and V3, open V1
  4. monitor G1
0935 Perform mixture throughput test at MC = 300 K using above procedure with 3He pump on. Let G1 rise to 530 mbar before Step 3, then it falls to 38 mbar and starts to rise. Throughput = 5.6 mbar/min.
0950 With 1K Pot speedivalve and needle valve closed, pump on Main bath with scroll pump.
Once P2 < 5 mbar, close pump valve then open 1K pot speedivalve and needle valve (5 turns), notice P2 rise a few mbar. Now pump out bath and 1K pot volume to < 1 mbar on P2.
0955 Close off scroll pump, then pressurize bath and 1K Pot (both sides) to about 0.5 bar with helium. Then pump it out again with scroll pump to < 1 mbar.
1005 Pressurize main bath and 1K Pot (both sides) with helium to 380 mbar +1atm on G3, then close 1K Pot speedivalve and needle valve.
1010 Let 5.4 mbar He exchange gas into IVC
1010 As on 2019 Oct 29 during the last attempted Run 71 cooldown, we will flow mixture through the fridge during LN2 cooldown. Let mixture from dump through cold LN2 Trap 2 to fridge, both sides. Then we'll isolate the sides and circulate with V6 open partially and mix open to dump. V9, V13b, V12b+speedi, V1, Condenser speedi, Still gate valves open, 3He pump on. Now open V6 to 12.8%.
1015 Circulation pressures settling to G2/G1/P1 = 650/719/0.24 mbar
1015 MC(Cernox) = 295.8 K, Sorb = >249 K (max), IVC = 5.4 mbar, G2/G1/P1 (circulation) = 650/719/0.14 mbar, Level resistor = 0.982 kΩ
1020 Begin LN2 transfer
looks like it might be a slow one. I filled the LN2 trap bath an hour ago, maybe Dewar pressure is low
1030 Try pressurizing the LN2 Dewar through the vent with N2 from the wall supply. Looks like it might be going a little faster, blowing out of the top bath port stronger.
1035 MC(Cernox) = 295.0 K, Sorb = >249 K (max), IVC = 5.4 mbar, G2/G1/P1 (circulation) = 655/721/0.26 mbar, Level resistor = 0.987 kΩ
1035 Close V12b speedivalve for 2 minutes to assess throughput. (Condenser pressure G1 should fall.) G1 falls at 10.6 mbar/min. Open V12b speedivalve again.
1045 MC(Cernox) = 289.5 K, Sorb = >249 K (max), IVC = 4.6 mbar, G2/G1/P1 (circulation) = 654/722/0.32 mbar, Level resistor = 1.002 kΩ
1045 Close V12b speedivalve for 2 minutes to assess throughput. G1 falls at 11.0 mbar/min. Open V12b speedivalve again.
1100 MC(Cernox) = 270.1 K, Sorb = >249 K (max), IVC = 4.0 mbar, G2/G1/P1 (circulation) = 655/722/0.40 mbar, Level resistor = 1.008 kΩ
1100 Close V12b speedivalve for 2 minutes to assess throughput. G1 falls at 12.0 mbar/min. Open V12b speedivalve again.
1120 MC(Cernox) = 236.2 K, Sorb = >249 K (max), IVC = 3.0 mbar, G2/G1/P1 (circulation) = 656/722/0.70 mbar, Level resistor = 1.046 kΩ
1120 Close V12b speedivalve for 2 minutes to assess throughput. G1 falls at 15.3 mbar/min. Open V12b speedivalve again.
1140 MC(Cernox) = 193.4 K, Sorb = >249 K (max), IVC = 2.5 mbar, G2/G1/P1 (circulation) = 657/722/1.80 mbar, Level resistor = 1.110 kΩ
1140 Close V12b speedivalve for 2 minutes to assess throughput. G1 falls at 20.1 mbar/min. Open V12b speedivalve again.
1205 MC(Cernox) = 151.8 K, Sorb = >249 K (max), IVC = 2.2 mbar, G2/G1/P1 (circulation) = 657/722/5.00 mbar, Level resistor = 1.223 kΩ
1205 Close V12b speedivalve for 2 minutes to assess throughput. G1 falls at 31.1 mbar/min. Open V12b speedivalve again.
1220 MC(Cernox) = 135.7 K, Sorb = 209.4 K, IVC = 2.2 mbar, G2/G1/P1 (circulation) = 657/721/8.50 mbar, Level resistor = 1.263 kΩ
1220 Close V12b speedivalve for 2 minutes to assess throughput. G1 falls at 38.6 mbar/min. Open V12b speedivalve again.
1245 MC(Cernox) = 117.3 K, Sorb = 160.5 K, IVC = 1.9 mbar, G2/G1/P1 (circulation) = 657/721/24.0 mbar, Level resistor = 1.299 kΩ
1245 Close V12b speedivalve for 2 minutes to assess throughput. G1 falls at 48.6 mbar/min. Open V12b speedivalve again.
1300 MC(Cernox) = 109.2 K, Sorb = 144.0 K, IVC = 1.9 mbar, G2/G1/P1 (circulation) = 657/720/36.0 mbar, Level resistor = 1.311 kΩ
1300 Close V12b speedivalve for 2 minutes to assess throughput. G1 falls at 52.8 mbar/min. Open V12b speedivalve again.
1330 MC(Cernox) = 97.2 K, Sorb = 128.2 K, IVC = 1.6 mbar, G2/G1/P1 (circulation) = 657/720/120 mbar, Level resistor = 1.323 kΩ
1330 Close V12b speedivalve for 2 minutes to assess throughput. G1 falls at 57.5 mbar/min. Open V12b speedivalve again.
1400 MC(Cernox) = 90.5 K, Sorb = 123.5 K, IVC = 1.6 mbar, G2/G1/P1 (circulation) = 657/719/650 mbar, Level resistor = 1.328 kΩ
1400 Close V12b speedivalve for 2 minutes to assess throughput. G1 falls at 57.9 mbar/min. Open V12b speedivalve again.
1405 MC(Cernox) = 88.3 K, Sorb = 122.6 K, IVC = 1.6 mbar, G2/G1/P1 (circulation) = 657/719/offscale mbar, Level resistor = 1.330 kΩ
1405 Stop LN2 transfer. Put ping pong ball over bath exhaust port, remove level resistor and put stopper on port.
1530 MC(Cernox) = 79.6 K, Sorb = 121.8 K, IVC = 1.6 mbar, G2/G1/P1 (circulation) = 655/719/offscale mbar
1530 Close V12b speedivalve for 2 minutes to assess throughput. G1 falls at 61.0 mbar/min. Open V12b speedivalve again.
1645 MC(Cernox) = 77.7 K, Sorb = 122.3 K, IVC = 1.6 mbar, G2/G1/P1 (circulation) = 655/719/offscale mbar
1645 Close V12b speedivalve for 2 minutes to assess throughput. G1 falls at 62.0 mbar/min. Open V12b speedivalve again.
1650 Stop circulation by closing V6. Turn off 3He pump.

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