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Helium temperatures in a four‐circle neutron diffractometer
Author(s) -
Herbert I. R.,
Campbell S. J.
Publication year - 1977
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889877012710
Subject(s) - cryostat , diffractometer , helium , liquid helium , materials science , refrigerant , physics , atomic physics , thermodynamics , condensed matter physics , composite material , scanning electron microscope , heat exchanger , superconductivity
The cooling of single‐crystal samples to helium temperatures within a four‐circle neutron diffractometer has been achieved by a novel continuous‐flow system. The system relies solely on helium for its cooling power with two flow circuits being used. The first delivers liquid to a reservoir cryostat of capacity 1–4 l located close to the Eulerian cradle of the diffractometer and the second draws the refrigerant from this cryostat via a flexible transfer tube into the sample region of a compact cooling unit mounted off the cradle. This arrangement allows unhindered motion of the diffractometer circles for sample temperature operation in the range 3.9–300 K. The system requires a total helium flow of 1.0 l h −1 to maintain a temperature of 20±0.1 K, decreasing to 0.5 l h −1 at higher temperatures.