| 0025 | Mixing chamber temperature has been falling gradually for the last couple of hours. It's currently at 9.6 K. Pressure in IVC is 4.6E-7 mbar. One possible reason for the decreasing base temperature is the presence of a leak. Another reason is that the 1 K pot may be at a lower temperature than the mixing chamber as liquid helium leaked into it during the helium transfer. This is common, but the 1 K pot temperature must be >7 K as it is beyond it's thermometer's range. Best to check what the situation is like in the morning. If the pressure in the IVC is higher and the temperature has been decreasing overnight, then it is almost certainly a leak. If the temperature has started to increase, the 1 K pot may have been the cause and we can continue with our plans to condense the mixture. |
| 1020 | Filled LN2 cold trap. |
| | Fed Cricket 4 pellets. |
| 1209 | IVC pressure fluctuating between 3.4 and 4.0E-7 mbar l/s. Close IVC. |
| | Open leak checker to hose leading to IVC. |
| 1217 | Leak rate for hose background jumped to 1.2E-7 mbar l/s. |
| 1227 | Leak rate is now 3.4E-7 mbar l/s. |
| 1233 | Background has stabilized to 3.8E-7 mbar l/s. |
| 1237 | Evacuating background hose for now. |
| 1300 | Hose background check: 1.5E-7 mbar l/s. Continue evacuating. |
| 1445 | Check of helium background leak rate in hose yields 6.9E-8 mbar l/s. Continue evacuating hose with turbo pump. IVC isolated. |
| 1900 | Check of helium background leak rate in hose yields 5.2E-8 mbar l/s. Continue evacuating hose with turbo pump. IVC isolated. |