Abstract: Holder (1) for a sample to be cooled to a low temperature in a vacuum space, comprising a carrier body (2) for carrying the sample in thermal contact and contact means (3, 4, 5) for bringing the carrier body into thermal contact with a cooling body to be brought to the low temperature, wherein the contact means can be switched between a first mode, in which there is no thermal contact between the carrier body and the cooling body, and a second mode in which there is thermal contact between the carrier body and the cooling body, and a probe for inserting into a vacuum space in a refrigerator such a holder for a sample to be cooled to a low temperature in this vacuum space, and a refrigerator, in particular a 3He-4He dilution refrigerator, adapted to accommodate such a probe.

Abstract: Holder (1) for a sample to be cooled to a low temperature in a vacuum space, comprising a carrier body (2) for carrying the sample in thermal contact and contact means (3, 4, 5) for bringing the carrier body into thermal contact with a cooling body to be brought to the low temperature, wherein the contact means can be switched between a first mode, in which there is no thermal contact between the carrier body and the cooling body, and a second mode in which there is thermal contact between the carrier body and the cooling body, and a probe for inserting into a vacuum space in a refrigerator such a holder for a sample to be cooled to a low temperature in this vacuum space, and a refrigerator, in particular a 3He-4He dilution refrigerator, adapted to accommodate such a probe.

Abstract: A dilution refrigerator of the type comprising a still and a mixing chamber connected by a heat exchanger is described. The heat exchanger provides a low impedance path between the still and the mixing chamber. All the parts of the dilution refrigerator are made entirely of plastics material.

Abstract: The measuring detector is constituted by the resistance of a given volume of doped semiconductor, there being formed on one face of a semiconducting monocrystal a surface region having a well-determined thickness and a well-determined concentration of doping ions and two electrical contacts at the extremities of said region.The doped surface region is obtained by ion implantation and there is formed on the second face of the monocrystal a metallic coating which has good thermal conductivity and is in good thermal contact with said second face.The detector is primarily applicable to thermometric measurements at very low temperatures below 1.degree. K.