| 0025 | Complete single-shot test. Mixing chamber temperature profile in Fig. 1. Mixing chamber temperature initially decreased from 466 mK to 464 mK at start of test, then started to rise. Lowest dump pressure recorded is around 32 mbar, which may give some idea of the amount of He-3 in mixture. Not sure if this occurred before, after or during initial rise in mixing chamber temperature. |
| | Not sure of reason for second clear decrease in temperature shown in Fig. 1. Perhaps this could be due to difficulty in keeping still pressure at 240 μbar through powering the still heater. At point at which mixing chamber temperature increased, dump pressure was around 62 mbar. |
| | Later variations in temperature can be safely ignored somewhat as they are due to trouble keeping still pressure high. |
| | Temperature of 1 K pot started to increase at 00:20. Probably due to heat load from still as heater was turned up to full power (199 mW). Reached 2.14 K before still heater was turned off to finish single-shot test. Temperature of 1 K pot then started to decrease. Pressure remained the same throughout the test at 55-60 mbar, so wasn't running dry. |
| 0050 | Stop and drain 1 K pot. |
| | Turn on mixing chamber heater, power 10 mW, to recover remaining mixture. |
| 0110 | It is taking a while to drain the 1 K pot. Temperature of 1 K pot is 1.49 K. It is possible that pump is inefficient. Perhaps this is a by-product of using it to pump acetone out of circulation lines! |
| | Stop evacuating 1 K pot. Open valve V5 on IGH to recover mixture from both sides of the fridge. |
| 0215 | Mixing chamber temperature is still a little low at 1.2 K and dump pressure is shy by about 100 mbar. Increase power of mixing chamber heater to 20 mW. |
| 0300 | Temperature of 1 K pot at 4.6 K. Mixing chamber temperature around 15 K and dump pressure 662 mbar. Still pressure P1 is 14 μbar. Most of the mixture has been extracted. Close all valves on fridge and IGH to leave it in safe state for tonight. Turn off mixing chamber heater. |
| 1010 | Open fridge lines to continue pumping mixture to dump. Fill LN2 cold trap. |
| 1130 | Remove He cold trap from bath, open to P2. |
| 1315 | P2=1.9 mbar worth of contaminate from He cold trap. Perform two rounds of He cold trap cleaning. |
| 1345 | Close V1 and V2 to isolate He cold trap from scroll pump. Pull LN2 cold trap 1 from dewar and open to P2. |
| 1436 | Collected 4.5 mbar of contaminate from cold trap 1. Perform two rounds of cold trap 1 cleaning. |
| 1506 | With mixing chamber temperature at 16.8 K, unplug Fischer connector #1. |
| 1658 | Place both cold traps back in respective baths, and fill LN2 cold trap dewar full. |
| 1706 | Mixing chamber temperature at 17.14 K, plug in Fischer connector to read Sorb temperature at 18.4 K. |
| 1758 | Open up line from turbo pump to IVC. Leave to pump out overnight. |
| 1809 | Sorb=17.6 K, Mixing chamber temperature=17.3 K. |
