Radioactive Isotope Study of the Dissociation of Barium Oxide under Electron Bombardment

Abstract

The evolution of Ba from BaO was detected by using radioactive Ba¹⁴⁰, and the rate was measured for various electron bombardment conditions. The following results were obtained: (1) When the bombarding voltage was fixed, the rate of evolution increased linearly with the number of primary electrons, provided the temperature of the oxide remained constant. (2) The rate of evolution increased exponentially with temperature; the activation energy was about 0.7 ev. (3) The efficiency of 500 ev electrons was far less than of 150 ev electrons at constant bombarding power. (4) The efficiency was around 3.9×10⁻⁷ atom per primary electron at 150 ev and 710°K. A simple mechanism of the electron bombardment dissociation is proposed.