A closed-cycle cryostat for optical and Mössbauer spectroscopy in the temperature range 4.2–300 K

A closed cycle cryostat intended for optical and Mössbauer investigations in the temperature range 4.2–300 K is described. Samples are cooled owing to the operation of a two-stage closed-cycle cryogenic refrigerator (CR) based on the Gifford-MacMahon cycle (with a refrigerating capacity of 1 W at T = 4.2 K at the second stage). The minimum temperature reached at the second stage of the CR was 2.7 K. The methods for reducing vibrations transferred from the CR to a sample are described in detail. The design proposed makes it possible to reduce the vibrational broadening of the resonance Mössbauer lines to a level of 10–15% at 5 K, thus exceeding the level of the best cryostat prototypes in the world.