Patent ID: 6017148
Filing Date: 2000-01-25
Classification: G01K

Abstract:
A device for optically measuring the temperatures of cryogenic fluids by analyzing the decay in the luminescence of a doped crystal, the device comprising a light source for exciting said crystal, optical fiber means for transporting the light flux emitted by said source to the crystal and for returning to a detection assembly the luminescent light emitted by the crystal as a result, and a measurement probe past which the fluid moves, wherein the doped crystal is constituted by one of the crystals from the group consisting of strontium fluoride doped with divalent ytterbium, SrF.sub.2 :Yb.sup.2+ and calcium fluoride doped with divalent ytterbium, CaF.sub.2 Yb.sup.2+, wherein said measurement probe is constituted by a housing having the doped crystal at an interior end thereof in the form of a crystal covering, a capillary surrounding the optical fiber means, the optical fiber means being placed in said housing facing said covering and defining a chamber between the end of said fiber and the covering, and wherein the housing includes at least one fluid inlet orifice disposed perpendicularly to the axis of the fiber and opening out into the chamber and at least one fluid outlet orifice opposite to the fluid inlet orifice.