The specific γ-ray constant and exposure rate constant of 182Ta



Reported values of the specific γ-ray constant Γ for 182Ta range from the original value of 6.1 to 7.692 R cm2h−1mCi−1, recommended in NCRP Report No. 41. The original calculation of Γ was based on inadequate nuclear spectroscopy and decay scheme data. The higher value of Γ occurs because of a computational error in the relative intensity of the 1.2575-MeV γ ray. Using nuclear spectroscopy data from the most recent Evaluated Nuclear Structure Data File (ENSDF), Γ is calculated to be 6.71±0.06 R cm2h−1mCi−1 and the exposure rate constant Γγ is 6.87±0.06 R cm2h−1mCi−1. These new calculations are presented and previously reported values of Γ and Γγ are reviewed.