| 0755 | IVC pressure = 5.4e-5 mbar |
| 0756 | Fill LN2 cold trap full. |
| 0810 | Go around one more circuit of tightening the lowest two IVC flanges. |
| 0820 | IVC pressure = 4.6e-5 mbar. |
| | Commence cryocleaning mixture through Cold Trap 2. Open V6 to 12.8% to get flow. |
| 0825 | Open leak checker to IVC, and isolate turbopump. Wait for leak rate to reach background. |
| 0830 | Increase V6 to 13.0%. |
| 0835 | Background leak rate = 2.5e-8 mbarL/s. Looking gooood! Let's spray test. |
| 0855 | Check all IVC flanges and EBox flanges. Leak rate steadily drops the entire time to 2.3e-8 mbarL/s. Loooooooks gooooooooood! Let's raise the dewar. |
| 0923 | Dewar raised. Switching back to leak checker. Begin pumping on main bath with scroll pump. |
| 0930 | Commence pumping out Main Bath. |
| 0935 | Background leak rate = 2.6e-8 mbarL/s. |
| 0940 | Cease cryoclean, pump mix to dump. Cold trap 2 may still have some mixture in it. Should pump out before cleaning. |
| 0945 | Flush main bath with He gas. |
| 0947 | Pump out 1K pot. With 1K pot spedivalve closed, briefly open needle valve to let some He gas from main bath into 1K pot to prevent anything else from leaking in. |
| 0949 | Slight rise in IVC leak rate to 3.1e-8 mbarL/s, but not a show stopper. |
| 0955 | Add 5.4 mbar He exchange gas to IVC. |
| | G2 (dump pressure)=778mbar |
| 0956 | As last cooldown, we'll leave some mix in the fridge during the LN2 transfer in hopes that it'll prevent a blockage. |
| | Opened gate and condenser valves, with v9 open, open 13a, 12a, cold trap 1 speedivalve and v1, v3 to let mix into the fridge through both sides. |
| 1000 | Commence LN2 transfer. |
| 1005 | G1/G2 = 671/602mbar. |
| 1037 | MC Temp = 279K. |
| 1110 | MC Temp = 232K. |
| 1155 | MC Temp = 169K. LN2 level resistor reads 1.117kΩ. It's getting close. |
| 1213 | MC Temp = 146K. LN2 level resistor reads 1.27kΩ. |
| 1259 | MC Temp = 114K. LN2 level resistor reads 1.29kΩ. End LN2 transfer. |
| 1436 | MC Temp = 92K. Start pumping on IVC to remove exchange gas (current IVC pressure = 2.5 mbar). |
| 1440 | MC Temp = 91K. Switch to turbo pump to pump on IVC. |
| 1502 | Close V3 and V13A, and open V6 to attempt pumping mixture to dump through fridge (a mini-throughput test, if you will). G1=666 mbar and G2=733 mbar after V6 was opened. |
| 1512 | G1=606 mbar, G2=739 mbar, showing a clear flow through the fridge lines. YAY! (P1=14ubar). Open V5 to commence pumping on both sides of the fridge. |
| 1523 | Close V6 in preparation for throughput test. |
| 1526 | G1=1 mbar, G2=782 mbar, P1=7 ubar. |
| 1535 | Open V9, V13A, V12A, cold trap 1 speedivalve, and V3 to let mixture through the cold trap into the still side of the fridge. G1 decreases to ~230mbar, then begins rising. Close V12A, cold trap 1 speedivalve, and V3, and open V1 to let mixture flow through fridge. G1 drops to ~22mbar. Throughput rate of ~10mbar. Most likely low due to small amount of mixture used/left in cold trap. |
| 1540 | Pump mixture back to dump. |
| 1630 | Mixture is back in dump, but we want it in the fridge lines, so close V6. Once closed, open V13A, V12A, cold trap 1 speedivalve, V1. P1 begins rising, which indicates we still have throughput, so that's hot. Open V3 to fill fridge lines from still side as well. |
| 1640 | Mixture sitting in fridge lines. IVC pressure seems to have increased. Pump out fridge lines to dump to see if there's a correlation. |
| 1645 | Mixture in dump. IVC pressure decreases to 3.4E-6 mbar. Let mixture back into fridge and monitor IVC pressure. |
| 1650 | IVC pressure has risen to 1.6E-5 mbar. Uh oh. We may have a leak from the fridge lines into the IVC. Will do this cycle once more while watching leak rate to ensure it's He. Pump mixture back to dump. |
| 1700 | Mixture in dump. IVC pressure has dropped to 3.4E-6 mbar. Switch to pumping using leak checker. Isolate turbopump. |
| 1710 | Background leak rate = 1.6E-5 mbarL/s. P1 = 1.6mbar. G1/G2 = 1.8/780 mbar. Close V5, open 13A, to let mixture in through Cold Trap 1. Watch leak rate… |
| 1712 | Leak rate jumps and rises to ~2.0E-3 mbarL/s and begins to show signs of plateauing before we decide to call it and pump mixture out of fridge and back to dump. Leak rate plateaus and then begins dropping during pumpout. |
| | When performing pump and flush, we backfilled the 1K Pot with He gas. If somehow this is leaking into the Main Bath when the warm mixture passes through the 1K Pot, and then if there's another leak from the Main Bath into the IVC, that could… possibly… explain things. Pump out 1K Pot with He4 pump to get rid of any remaining He gas anywhere in the system besides the fridge lines. |
| 1720 | Cease pumping out 1K pot. Close 1K Pot speedivalve, close V4A, and manual valve on He4 pump. Turn off He4 pump. Begin closing V6. |
| 1727 | V6 closed. Leak rate = 7.6E-6. G1/G2 = 1.5/780 mbar. P1 = 7ubar. Close V5, open V13A and V3 to let mixture back into fridge. Leak rate still increases dramatically. |
| 1730 | Leak rate = 1.7E-3 mbarL/s. Pump mixture back to dump. Leak rate plateaus again, and begins dropping. |
| 1732 | Leak rate = 1.4E-3 mbarL/s. We strongly suspect a cold leak in the fridge lines. |
| 1747 | It's been decided, we gotta warm up. We'll turbopump on the fridge lines over the weekend to get the leak rate low enough to do a leak check through the Vent port later. |
| 1820 | There is one final idea. Perhaps the He in the clear hose from the wall to the pumping manifold is leaking through the green valve, and that's somehow correlating to when we put mixture into the fridge. So we're pumping out that line, then trying this stuff again. Begin closing V6 to get ready for this test. |
| 1830 | After pumping out the clear line with the scroll pump, isolate scroll pump and open IVC to leak checker. Wait for leak background to stabilize. |
| 1837 | Leak rate is currently 7.2E-7 mbarL/s and still dropping, close V5, open V13A, and watch the leak rate as mixture enters the fridge. 2.8E-5 mbarL/s isn't that bad, right? Guys? Is this thing on? |
| 1840 | Pump to dump. Leak rate begins dropping. Isolate and turn off leak checker. |
| 1900 | Add 6.3mbar of He exchange gas into IVC in preparation for warm up. |
| 1905 | Drop dewar. Attach bag, blow out LN2 from inside dewar. |
| | While lowering dewar, the vibrations from the lowering cable caused the flange that it touches (the flange on the end of the bellows leading to the Gate valve) to become undone. It did not come off the bellows, nor did the vacuum break, as evidenced by no change on the IGH. So everything is fine, this is just a strange coincidence, and should be watched for in the future when raising and lowering the dewar. (This could not have accounted for the leak in the circulation lines to the IVC, so our warm up is still warranted). |
| 1910 | Open V12B and Cold Trap 2 speedivalve to pump out whatever might still be in Cold Trap 2. Attach pumping manifold to Vent port on back of IGH. |
| 1930 | Commence closing V6 to begin isolating mixture in dump. |
| 1935 | Close V12A/B and both cold trap speedivalves. Close V5, and V9, and manual dump valves. Turn off He3 pump. Open Vent speedivalve to begin scroll pumping out IGH lines. Open V7, V2, V3 to expose dilution lines to scroll pump. Wait until pressure is small enough, which is basically immediately, then switch to turbopump. |
| 1945 | Pumping out dilution lines using turbo pump. Pressure on turbopump sensor reads 4.0E-5. P1 = 9ubar. |