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Sample cooling

Warning: for manipulation with LN2 always use protective gloves and glasses!

The sample can be cooled down to 100-150 K in 20-60 minutes, depending on the manipulator and sample mounting.

The temperature can be observed on the Eurotherm 3508 unit.

Manipulator cooling

  1. Install the grey LN2 tank at the manipulator inlet and the bottle at the outlet. Carefully cover all connection with thermal insulation.
  2. Fill the tank with about 3 litres of LN2 (i.e. 3 polystyrene jugs) and cover it with the pink cap.
  3. Wait until you reach the desired temperature.
  4. Refill the LN2 tank when needed. The consumption of LN2 is about 1 litre per hour.

Manipulator thawing

  1. Check that LEED, electron analyzer, X-ray source, evaporators etc. are off and that the electropneumatic valve 10 towards the beamline is properly closed.
  2. Disconnect the bottle from the manipulator outlet.
  3. Connect the compressed-air line to the manipulator outlet and slightly open the valve in order to blow out LN2 and humidity. It might take several hours. and high peaks on the pressure in the chamber (10-6 mbar or more) might appear.
  4. You can anneal the sample at 300 K or more in order to help thawing.
  5. You can run some titanium sublimation pump cycles in order to help the pressure to recover.

Refilling the dewar

  1. Open the 3-way valve in order to make sure that the dewar is not pressurized.
  2. Bring the dewar to the refilling station.
  3. Release the KF50 clamp, remove the tubing and the seal (centering ring with O-ring gasket).
  4. Put the filling hose into the dewar and fix it with the wire.
  5. Check that the release valve is closed and open the outlet vave.
  6. Set the timer (TEMPO DI CHIUSURA VALVOLA) to 7 minutes and open the electropneumatic valve by pressing the green button (APRE}.

  1. Observe the process. If LN2 start splashing out of the dewar close the electropneumatic valve by pressing the red button (CHIUDE). If the dewar is not full after 7 minutes add some more time.
  2. Close the outlet valve and remove the filling hose from the dewar.
  3. Install back the tubing into the dewar (do not forget the seal) and fix it with the CF50 clamp.
  4. Check that the 3-way valve is closed.
  5. Bring the dewar back to the laboratory.
  6. The dewar will pressurize itself in several minutes. If you need LN2 immediately, pressurize is from the compressed-air line through the 3-way valve.
  7. After 1 hour check that the KF50 clamp is properly tightened.

Last Updated on Tuesday, 21 November 2017 13:07