CryoStat Operating Instructions

The cryostat provides automatic analysis temperature control over a wide range of sub-ambient temperatures.

 
  • Read and fully understand this entire section prior to carrying out operations on the system.
  • All  system components must be powered ON in the sequence provided in this section.
  • Pay attention to all local safety systems and requirements and consider the specifics of the experiment when operating the system.
  1. Prior to starting any analysis on the system, ensure the following:
  • Go to Unit [n] > Enable CryoStat and ensure a checkmark displays to the left of the menu option. A checkmark indicates the item has been selected and disables the elevator during an analysis when using the cryostat.
  • The cryostat is correctly mounted and held firmly in place by the metal retaining bands.
  • Release the brake on the cryostat cradle and move the system upwards to check that the sample well and the analyzer sample port is correctly aligned.
  • Check that the vacuum connection, helium connection, and wired connections to the compressor and temperature controller are in place and correctly fitted.
  1. Prepare the samples:
  • Samples can be prepared in-situ using the analyzer heating mantle (if the heating mantle fits with the cryostat installed). This will depend on the type of heating mantle used.
  • The cryostat can be prepared to run analyses in the DOWN position while the samples are being prepared. Leave the insulating cover for the cryostat sample well in place while doing this.
  1. Turn on the helium supply and adjust the rotameter to scale position 55. This corresponds to a flow rate of approximately 5 ml/min. See Rotameter Scale Readings.
  2. Allow the helium to purge the sample well for fifteen minutes. This purge procedure removes water vapor from the sample well and prevents water vapor from freezing when the system is in use at sub-ambient / cryogenic temperatures.
  1. Open the degas port 2 valve to the cryostat to ensure a good vacuum inside the cryostat vacuum jacket.
  2. Power ON the compressor — first switch the circuit breaker to the UP position and then power ON the analyzer. The compressor will now start to pump.
  3. Press the ALL OFF button to power ON the temperature controller. Set the required temperature on the temperature controller or in the analysis application. If using the temperature controller, refer to the temperature controller manual supplied by the manufacturer.
  4. Create a sample file (see Create Sample Files). There are settings specific to physical adsorption analyses using a cryostat in Analysis Conditions.
  5. With the sample tube in place, preparation completed, and the tube cooled to ambient temperature, slide the insulating cover up so that the cover fits snug against the mouth of the raised cryostat.
  6. When prompted by the analyzer application, raise the cryostat.
  7. Allow the sample to thermally equilibrate before starting the analysis.
  8. When prompted by the analyzer application, lower the cryostat.
  9. If the sample tube is to be removed, go to Unit [n]> Enable Manual Control and pressurize the sample tube to 760 mmHg at ambient temperature. See Enable Manual Control.
  10. Weigh the sample after analysis and enter the sample weight into the sample file. See Determine the Sample Mass for Physical Adsorption.
  11. The cryostat can now be used to analyze another sample at the same temperature or change the set point temperature. It is recommended that the cryostat remained powered ON unless left unused for a long period of time. If it is necessary to power OFF the cryostat, set it to ambient temperature and allow it to come up to room temperature.
 
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