Use of a single-stage, closed-cycle cryorefrigerator for routine measurements at moderately low temperatures on a four-circle neutron diffractometer

A single-stage closed-cycle helium cryorefrigerator has been installed on a conventional four-circle neutron diffractometer. The cold head together with a specially designed support and alignment unit are sufficiently compact to enable it to be mounted directly onto the φ rotation table within the χ circle in place of the normal goniometer head used for room-temperature experiments. The device has a temperature range of 50 to 300 K, is extremely simple to use, and has a low operation cost as no cryogenic liquids are consumed. There are additional restrictions on the diffractometer angles but, with care, it is possible to measure at least half the reciprocal sphere.