Relative intensities of prompt γ-rays from the 35Cl(n,γ)36Cl reaction with thermal neutrons as secondary γ-ray intensity standards

The relative intensities of 16 prompt γ-rays from the 35Cl(n,γ)36Cl reaction with a thermal neutron were precisely determined as secondary γ-ray intensity standards with HPGe detectors. The detection efficiencies were calibrated from 0.2 to 10.8 MeV using the standard sources 152Eu and 56Co and the 14N(n,γ)15N reaction. We performed appropriate analyses for the evaluation of doublet peaks, subtraction of mixing with escape γ-rays and other corrections; consequently, the values were determined within 1% accuracy. Relative intensities in the range of 0.7 to 8.6 MeV are proposed as reliable secondary standards for 16 γ-rays.

► The relative intensities of prompt γ-rays from the 35Cl(n,γ)36Cl reaction were measured with three HPGe detectors.
► The escape peak ratios were simulated by GEANT4 and compare the experiments.
► Useful secondary γ-ray intensity standards were proposed.