Circulate Mixture

Once the mixture has condensed, it can be circulated through the fridge. In the beginning of the circulation process, the mixture is slowly let into the circulation lines via V6. This process can be done automatically with LabVIEW or manually. Both processes will be described below. The manual process will describe in more detail what's happening in the automatic process.

1. Make sure V9 is closed.
2. (Skip this step if using a specific amount of mixture) Open V14A - this connects the dump to the still pumping line and will bleed mixture out of the dump.
3. Open V6 slowly. Start at 12.5%.
4. Monitor the pressure in G2. It shouldn't go above 200 mbar as you open V6 little by little. Once V6 is at 17.5%, the valve can be opened all the way without worrying about the pressure going above 200 mbar in G2.
   [This is out of date. It was written when the amount of mixture in use was very low. The limiting pressure should be considered higher, perhaps 500 mbar or even 800 mbar.]
5. (Skip this step if using a specific amount of mixture) With V6 fully open, when G1 and G2 pressures drop and stabilize, close V14.

1. Make sure V9 is closed.
2. (Skip this step if using a specific amount of mixture) Open V14A - this connects the dump to the still pumping line and will bleed mixture out of the dump.
3. Make sure the “Condense In\ process is closed.
4. Click on the “Circulate\ button. It will again ask to make sure you are ready for this process to begin, and when you confirm this, circulation will start.
5. (Skip this step if using a specific amount of mixture) With V6 fully open, when G1 and G2 pressures drop and stabilize, close V14.
6. Abort the Circulation program (this doesn't stop the physical circulation process going on). You MUST remember to abort the program or issues will arise when flashing the detector, which can temporarily raise the pressures in G1 and G2 higher than 200 mbar. If this happens, V6 will close to try to remedy this.