A precise determination of the half-life of tritium and of the average energy released by the decay has been carried out. The half-life was determined from measurements of the quantity of tritium contained in a sample and the rate at which that quantity gave rise to ${\mathrm{He}}^3$. The average energy release was determined from additional measurements on the same sample of the rate at which the sample liberated heat. The value found for the half-life was 12.46±0.1 years. That found for the average energy released by decay of neutral tritium to neutral helium was 5.69±0.04 kev.

• Received 21 August 1950

DOI:https://doi.org/10.1103/PhysRev.80.990