2012/07/06
| 0030 | Fill N2 cold trap full. |
|---|---|
| 1005 | Filled LN2 cold trap. |
| 1220 | Mixing chamber temperature 89.7 mK. Let's try to isolate the fridge. Unplug pumps and detach dewar from pulley system. |
| 1415 | Well that did nothing… turn on still heater again (1 mW) and wait. See what happens. |
| 1610 | Mixing chamber temperature has increased to 99.8 mK. Pressures of G1, G2 & P1 are 54 mbar, 62 mbar & 0.08 mbar respectively. Other temperature stages: |
| Table 1: Temperatures of stages when still heater powered to 1 mW. | |
|---|---|
| Stage | Measured Resistance [kΩ] |
| Still | 4.46 |
| Cold plate | 14.9 |
| Mixing chamber | 20.8 |
| 1615 | Increase still heater power to 2 mW. |
|---|---|
| 1800 | Mixing chamber temperature has increased to 109.6 mK. Pressures of G1, G2 & P1 are 56 mbar, 69 mbar & 0.095 mbar respectively. Other temperature stages: |
| Table 2: Temperature of stages when still heater powered to 2 mW. | |
|---|---|
| Stage | Measured Resistance [kΩ] |
| Still | 4.41 |
| Cold plate | 14.9 |
| Mixing chamber | 19.1 |
| 1805 | Increase still heater power to 3 mW. |
|---|---|
| 1905 | Mixing chamber temperature has increased to 116.8 mK. Pressures of G1, G2 & P1 are 60 mbar, 73 mbar & 0.11 mbar respectively. Other temperature stages: |
| Table 3: Temperature of stages when still heater powered to 3 mW. | |
|---|---|
| Stage | Measured Resistance [kΩ] |
| Still | 4.38 |
| Cold plate | 14.9 |
| Mixing chamber | 18.0 |
| 1915 | Increase still heater power to 4 mW. |
|---|---|
| 1945 | Start helium transfer. Helium liquid level 25.7%. |
| 2036 | End LHe transfer (91.3%) |
| 2110 | Mixing chamber temperature has increased to 119.0 mK. Slight decrease from peak temperature witnessed (<1 mK), which may have to do with helium transfer. Pressures of G1, G2 & P1 are 71 mbar, 82 mbar & 0.12 mbar respectively. Other temperature stages: |
| Table 4: Temperature of stages when still heater powered to 4 mW. | |
|---|---|
| Stage | Measured Resistance [kΩ] |
| Still | 4.38 |
| Cold plate | 15.0 |
| Mixing chamber | 17.8 |
| 2120 | Increase still heater power to 5 mW. |
|---|---|
| 2305 | Mixing chamber temperature has increased to 120.8 mK. Pressures of G1, G2 & P1 are 79 mbar, 87 mbar & 0.13 mbar respectively. Other temperature stages: |
| Table 5: Temperature of stages when still heater powered to 5 mW. | |
|---|---|
| Stage | Measured Resistance [kΩ] |
| Still | 4.37 |
| Cold plate | 14.9 |
| Mixing chamber | 17.6 |
| 2310 | Turn still heater off. |
|---|---|
| 2335 | Fill N2 cold trap full. |