2023/10/23 (Monday)
* Lab in-personnel: Himangshu, Ping
| 1000 | IVC closed and pressure valve closed. CVJ on turbo overnight. Main Bath is up(fridge closed) |
|---|---|
| 1005 | Turbo failed overnight. This is the 2nd time in a row that the pressure was low enough (<1e-1 mbar) for us to leave it overnight and then it has failed for some reason. |
| 1005 | Connect the scroll, pumpout the lines with scroll, open valve to CVJ and pump it out as well. Then switch to turbo once pressure below 1e-1 mbar. |
| 1033 | The pressure was dropping very slowly with the scroll and I redid the joint at the CVJ and replace the KF flange seal ring with another one. |
| 1127 | Although the scroll was slowly went to 1e-1 mbar, the turbo failed even when it was valved out. I restarted the turbo and doing a leak check to see if there is any leak at the CVJ joint or CVJ itself. |
| 1139 | The turbo failed again even when it was below 1e-1 mbar. I valved out the CVJ and turbo working fine. This let me believe there is a leak at the CVJ (We used less number of washers during the Main Bath install, is that the reason?). Connected leak detector to test this. |
| 1149 | IVC is valved out at the top of the fridge. CVJ is valved out. Turn on leak detector. Leak= 4.18 pbarL/s and stable. |
| 1150 | Valve out turbo. Leak at 12 pbarL/s and stable. |
| 1156 | Squirt He gas on CVJ joints. No change |
| 1158 | Open CVJ port. Leak jumped to 63 pbarL/s and falling slowly. |
| 1159 | Squirt He gas on top of CVJ along joints. No change! |
| 1209 | This disproves that there is any leak at the CVJ. Pumping down with turbo again with the leak detector still connected |
| 1213 | Turbo failing. Switch to scroll and keep it along with the leak detector for a while. Turbo restarted |
| 1400 | Check contents of warm LN2 Trap 1: 12.9 on G1. Pump it out with the scroll pump. |
| 1401 | G1 = 0.3 mbar and stable, stop pumping on Trap 1 |
| 1402 | Insert cold trap 1 into and begin filling the LN2 cold trap dewar with LN2 |
| 1407 | Begin cryocleaning mixture through cold trap 1 following the procedure in procedure:cryoclean_mixture |
| 1412 | Open V6 to 11.7% to restart flow |
| 1417 | Open V6 to 12.0% to restart flow |
| 1425 | Open V6 to 12.1% to restart flow |
| 1426 | Although the turbo didnt hold the CVJ, but the pressure on CVJ without any pump is 74 ubar and with the roughing pump on the leak detector, 25 ubar, which is within our range of work CVJ in Run 76. We proceed with the setup. Close the CVJ at the top of the fridge and pumpout the line below 1e-5 mbar to open the IVC valves. |
| 1647 | End cryocleaning mixture through trap 1. Pump mixture to dump |
| 1715 | P1 = 0.060 mbar, G1 = 1.5 mbar and stable. Close all valves and turn off 3He pump, leaving 719.5 mbar in dump |
| 1718 | Remove cold trap 1 from the LN2 bath to warm up overnight |