Ionization coefficients in nitrogen containing radioactive impurities

Abstract

Values of the Townsend coefficients α and ω/α have been obtained over the range 100 < E/p0 < 510 v cm−1 torr−1 for contaminated nitrogen samples; the contaminants used were the radioactive isotopes tritium and krypton-85. Two impurity concentrations were used for each contaminant: 6 μCi cm−3 and 60 μCi cm−3 respectively. Values obtained for the primary coefficients in these contaminated samples were significantly higher than those in pure nitrogen. This increase in α/p was attributed to the preferential ionization of long-lived metastable states of nitrogen, which were produced by the decay radiations of the included isotopes. This conclusion was supported by the breakdown of the similarity principle found to occur for Paschen curves during the present work. No significant difference in the secondary coefficients for the pure and contaminated nitrogen was observed.