Sensitive Tritium Counting with a Propane Proportional Counting System

Abstract

Comparison of the minimum detectable amount of tritium by different counting devices shows that proportional gas counting is the most sensitive method at the present time. A new method of tritium proportional gas counting using propane as counting gas is described. The propane is formed by hydrogenation of propyne with palladium oxide as a catalyst. Using a 2.5‐liter counter filled with propane at 2.2 atm pressure requires a sample size of half a mole of H₂O or H₂. For a background of 5.3 cpm, this results in a minimum detectable concentration, without isotopic enrichment of tritium, of 3 TU equal to ±2σ for a counting time of 1000 min.