Investigation on 50 Ω Rhodium–Iron Sensors with Ceramic Shell

Rhodium–iron sensors with a ceramic shell and 0.03 mm diameter wires drawn from 0.05 mm diameter wires have been investigated. Results indicate that a proper annealing process is required for the drawn wires to be used in the sensor. The stability of the 30 thermometers made in this way were investigated after being exposed to 20 thermal cycles between 4.2K and room temperature. The thermometers remained stable at 273.15K within 10mK. A standard reference curve was obtained by 58 calibration points from 1.2K to 300K for ten thermometers. With this curve, the R – T relationship was fitted for the other sensors in the same batch within 0.1K accuracy with just a few temperature points. Finally, the self-heating effect was discussed. The results indicated that the performance of the thermometers with drawn wires are the same as that of the thermometers with the original 0.03 mm diameter wires.