REPRODUCIBILITY OF SUPERCONDUCTING TRANSITION-TEMPERATURE OF ENCAPSULATED SAMPLES OF INDIUM USED AS TEMPERATURE FIXED-POINT

The results of superconducting transition temperature measurement repr oducibility in indium samples, collected over two years, are presented . The measurements were performed on samples prepared in the way which , in the authors' opinion, diminishes non-reproducibility of the trans ition temperature; by encapsulation of indium samples into glass cells a T(c) reproducibility better than +/-0.1 mK is obtained. These resul ts led the authors to propose the use of the superconducting transitio n of indium for calibration of an interpolating gas thermometer, reali zing the International Temperature Scale 1990 in the temperature range 3-25 K.