Reliability of Prompt γ-Ray Intensities for the Measurement of Neutron Capture Cross Sections

Abstract

Articles you may be interested inDetermination of radiative neutron capture cross sections for unstable nuclei by the γ-ray strength function method AIP Conf.Abstract. We examined the reliability of prompt γ-ray intensities by measuring ratios of thermal neutron capture cross sections on 23 Na, 27 Al, 51 V, 55 Mn, 64 Ni, 65 Cu, 141 Pr, 186 W, and 197 Au at the Kyoto University Research Reactor Institute. The cross sections were obtained by two methods: the first is detecting prompt γ-rays (which we call the prompt-γ method), and the other is detecting γ-rays following β-decay (the activation method). Intensities of prompt γ-rays and decay γ-rays have been reported to have an uncertainty of about 5% and 1%, respectively. It is found that values of 65 Cu and 186 W have large discrepancies in the results of the two methods, by about 30%. The disagreement would be caused by inaccuracy of the absolute intensities of prompt γ-rays. The inaccuracy is estimated to be due to the incompleteness of level schemes and the detector efficiency of prompt γ-rays. We need to examine absolute intensities of prompt γ-rays when we use the prompt-γ method.

Precise Intensity Measurements in the14N(n, γ)15N Reaction as a γ-Ray Intensity Standard up to 11MeV

“…On the other hand, the values reported by Belgya agreed within 2-3% in the 2-8 MeV region; nevertheless, the ratios showed a small oscillation versus -ray energy. Using the HPGe detectors calibrated using the results of the present work, we are going to measure the neutron capture cross sections 20) and precise intensities of the 35 Cl(n,) and 27 Al(n, ) reactions as secondary intensity standards.…”