Nitrogen cryostat for study of Moessbauer scattering

A cryostat for experiments in Moessbauer scattering is described. Without a vacuum system and using only mechanical methods, the nitrogen temperature is reliably maintained on a gamma emitter in a block with a mass of approx. 20 g moving on a shaft approx. 300 mm long according to a given law with high accuracy for a sufficiently prolonged period.