Borehole logging tool cryostat

Abstract From the Canadian patent

A borehole logging tool and cryostat therefor to maintain a semiconductor detector at cryogenic temperatures. The cryostat has an elongate single-phase heat sink of solid, thermally conductive material on which the detector is removably mounted. The other end of the heat sink is arranged to receive a liquid cryogen or the cold finger of a helium refrigerator, which is removed before a logging run; the detector being maintained at cryogenic temperatures during the logging run by absorption and retention of heat in the solid, single-phase heat sink. A rigid tube having similar thermal capacity and similarly pre-cooled to cryogenic temperatures, surrounds but is spaced from the heat sink.