X-ray diffractometry on polycrystalline materials between 300 and 4.2K: problems concerning the method of cooling the sample

Abstract
The main difficulties in crystallographic studies between 300 and 4.2K are the cooling method and the measurement of the sample temperature. The apparatus described consists of a monochromator and a vertical axis goniometer with the cryostat containing the sample. A proportional counter is used as a detector and the diffraction information is recorded with a ratemeter or by step scanning. On the basis of several examples, three sample cooling techniques have been compared and discussed using different thermal conduction processes between the cooling support and the powder.