Radiometric Sensing of Atomic Hydrogen in Trace Quantities

This study was undertaken to evaluate radiometric techniques for sensing atomic hydrogen in trace quantities at low pressure, for possible application to satellite measurements. A reaction utilizing radioactive As⁷⁴ metallic surfaces demonsrated quantitative evolution of As⁷⁴ H₃ vapor in linear relationship with the impingent flux of atomic hydrogen. Equivalent partial pressures of atomic hydrogen below 10⁻⁸ torr were quantitatively measured.