MEASUREMENTS OF BREAKDOWN VOLTAGES AND V-I CHARACTERISTICS IN SELENIUM AND TELLURIUM VAPORS

Measurements of breakdown voltages and V-I characteristics have been c arried out, using co-axial cylindrical electrodes in selenium and tell urium vapours in the pressure range of 6 x 10(-3) to 1.131 kPa. A high temperature heat-pipe apparatus developed in our laboratory for deter mining the electrical and plasma properties of metal vapours was used in the present study. The breakdown voltages obtained in selenium (Se) and tellurium (Te) vapours are higher than diose obtained by earlier workers in mercury (Hg), sodium (Na), potassium (K), cadmium (Cd) and zinc (Zn) vapours under similar conditions. Since the studies were car ried out in metals in their vapour state, the theory of gas breakdown is considered to explain the variation in the data obtained. The inves tigations clearly show that the V-I characteristics are pressure depen dent and do not exhibit any negative current growth.