On the SiO2–OH capacitance low-temperature thermometers
Résumé
Abstract : Abstract Capacitance thermometry seems to be the best solution for low-temperature measurements in a high-magnetic field. Vitreous OH-doped silica suits well to this use. A parallel plate capacitor is not very suitable when applied in vacuum, since thermalization against a flat substrate introduces stray-capacitance perturbations. Using vapour deposition of gold, we have prepared an inter-digital pattern of electrodes leaving one face of the slab free. Very small surface area of the electrodes minimizes eddycurrent heating. Relaxation effects could be reduced by careful annealing which removed water molecules from the sample surfaces. Some SiO x layers with controlled OH-content were also prepared by plasma deposition (PACVD).