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Operation
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Cryostat cool down
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Evacuation
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Prior to cool down, connect a turbo molecular or diffusion pump to the valve or port and evacuate the shroud to base pressure (about 1E-5 mbar). It is possible to keep pumping during operation. Outgassing and O-ring permeation will cause the pressure to rise slowly over time; therefore, periodic re-evacuation may be necessary. Re-evacuation is required when the minimum temperature that can be reached begins to increase.

Cool down
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#. Switch on the electronic driver, start the software (see :ref:`websq_inteface`) and observe the temperature reading. The typical temperature value ranges from 290 K to 300 K.
#. Choose the proper frequency (50 or 60 Hz) using the toggle switch located on the cold head drive unit. Make sure that the toggle switch marked "cold head drive switch" located at the lower right rear of the compressor is turned off. This switch is only used during maintenance, and should remain off during normal operation. The main power switch on the front panel of the compressor should now be turned on, followed by the drive switch on the front panel. The temperature should begin to drop within a few seconds. The base temperature is reached after about 5 hours.

Warm-up
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To shutdown the system, turn off the compressor and the electronic driver. If the interconnecting gas lines need to be removed for any reason, allow the system to completely warm-up to room temperature before the gas lines can be disconnected. This takes approximately 5 hours.
