| 1540 | Fill N2 cold trap full. |
| | Mixing chamber temperature 7.12 K, same as it was yesterday evening. |
| 1545 | Helium leak level in pipes leading to IVC 1.7E-9 mbar l/s. Open up IVC and helium leak rate is 2.8E-6 mbar l/s. |
| 1550 | Fed Cricket 4 pellets. |
| 1620 | Begin LHe transfer (28.1%). |
| 1650 | End LHe transfer (73.6%). |
| 1925 | Helium leak level in pipes leading to IVC 3.0E-9 mbar l/s: a little higher due to the background from the helium transfer. Open up IVC and helium leak rate is 5.2E-7 mbar l/s and falling: lower than expected. I assume this is because during the transfer, some helium did get into the 1 K pot and the 1 K pot temperature did fall to 6.1 K. The decreasing leak rate would also indicate this. Mixing chamber temperature is currently falling, and has reached 6.56 K. I suspect that the 1 K pot has some liquid helium in it and is acting like a cryopump. |
| | Isolate IVC and attempt to pump out helium from 1 K pot. |
| 1940 | Stop pumping on 1 K pot. Wait for it to warm up. |
| 2210 | Helium leak level in pipes leading to IVC 1.9E-9 mbar l/s. Open up IVC and helium leak rate is 3.5E-7 mbar l/s and falling. Mixing chamber temperature is at 6.46 K and rising. It is possible that 1 K pot is still acting as a cryopump. It may be best to conduct further leak checks tomorrow to be sure. |
| | Slightly concerning that 1 K pot is still acting like cryopump. If we find that leak rate is still this low tomorrow, maybe this is our true leak rate. Not sure where the helium has disappeared to though… |
| | Isolate IVC. Pump on lines leading to IVC with turbo pump. |
| 2350 | Fill N2 cold trap full. |
| | Fed Cricket 4 pellets. |