Cryocoolers

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The cryocooler is manufactured by CYRO Industries of America, Inc..

Close-circle cryostats are installed in <QM>2 allowing samples to be comprehensively studied in a wide range of temperatures from 12K to 500K. The cryocooler can operate both helium (12K to 300K) and nitrogen gas (300K to 500K ) using a single stream flow. In-house nitrogen and helium gas are used for cryocoolers. Just by switching the knob outside of the hutch, the gas supply can be altered.

The external tip-heater prevents frost and maintains a dry tip that helps to create an ice-free sample environment at low temperatures. A platinum temperature sensor is installed to control the low alarm setting temperature that triggers back the temperature controller to energize and maintain the ice-free environment.

The main component of the cryostat can be divided into five different components:

  • (i) source : the refrigerator or the cryostat act as a source to cool a reliable cryogenic temperature for a long continuous periods

  • (ii) compressor

  • (iii) PID temperature controller : Cryogenic temperature controlled Model 336 manufactured by Lake Shore is used. The controller’s zone tuning feature allows you to measure and control temperatures seamlessly from 300 mK to over 1,500 K by automatically switching temperature sensor inputs [1].

  • (iv) Power supply : 30 V digital and 24V DC are used

  • (v) Gas flow controller : The digital flow automatically control and displays the flow rate

Gas flow parameters
Helium gas: Normal flow rate is between 8 – 12 liters/min, typically 11 l/min Nitrogen gas : Normal flow rate is between 8 – 12 liters/min, typically 9 l/min.

Safety

  • Do not touch the cold helium and nitrogen gas stream. Exposure to the skin of the cold gas could result in severe injuries.
  • The dewar system has pressure relief protection installed. Do not remove pressure reliefs or check valves.

Motors

Motor Commands Comments
Temperature controller sampleT Set the temperature

To open the lakeshore

  • Step 1:Open terminal
  • Step 2: > cd
  • Step 3: > /mnt/home/chess_id4b/.cs-studio
  • Step 4: click okay
  • Step 5: In the file you can find the recent window for lakeshore.opi
  • Step 6: click lakeshore 2
  • Change the Range : Rang3/High

Practical guide of the temperature switch between nitrogen and helium

Temperature change guideline