7.13 Measurement of Specific Heat at Low Temperatures

A cryostat for experiment at low temperature is shown in Fig. 7.20. It consists of a Dewar's flask containing liquid nitrogen. Inside this flask, there is another Dewar's flask containing liquid helium. A metal ring with taper end is sealed to the inner flask. This is connected to a metal cap through rubber gaskets. Experimental equipments are placed inside a thin-walled metal tube of Monel or super nickel hung from the metal cap by a fibre. Since helium can diffuse through pyrex glass, provision is made to pump out the gas from the double-walled region of the inner flask.

 

Cryostat for experiment at low temperature

 

Fig. 7.20 Cryostat ...

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