Superconducting transition temperature and low temperature resistivity in the niobium-hydrogen system

The impact-ionization rate in InSb at 300 K between 200 and 500 V/cm is found to beg(E)=210⁹ exp (–10³/E)s^–1 withE being the electric field (V/cm).We use current-voltage characteristics measured by A.C. Prior in 1957 [1]. In evaluating the impact-ionization rate we take into account Auger and linear recombination, surface generation,z-pinch compression, and doping of the sample. We also discuss the effects of ohmic heating and change in electron temperature. The rates evaluated from four independent measurements done by Prior agree reasonably well.