Prompt gamma rays induced by inelastic scattering of fission neutrons on iron

Zeljko Ilic,Thomas Brückel,Zsolt Révay,Eric Mauerhofer,Matthias Rossbach,Tsitohaina H Randriamalala,Christian Stieghorst

doi:10.1007/s10967-020-07271-w

Abstract

Prompt gamma rays induced by (n,n′γ) reactions on iron were measured with the instrument FanGaS (Fast Neutron induced Gamma-Ray Spectrometry) operated at the Heinz Maier-Leibnitz Zentrum (MLZ) in Garching. The measurement was performed at an angle of 90° between neutron beam and detector. The fast neutron flux at the sample position was determined to be 1.40 × 108 cm−2 s−1 by using the foil activation method. Energies, relative intensities and fast neutron spectrum averaged isotopic cross section for production of 81 prompt gamma lines are presented. The results obtained are found in good agreement with literature data. The new set of gamma lines is recommended to replace the old dataset with several new lines also recognizing a few false identifications. This work is an important step towards the future chemical analysis of large samples at FanGaS employing highly penetrating fission neutrons.

Highlights

Accurate non-destructive chemical analysis of materials is of fundamental importance in many fields of science and for industrial applications
Prompt Gamma Neutron Activation Analysis (PGNAA) based on cold/thermal neutron capture is well established as a powerful non-destructive analytical technique to determine the elemental composition of small and thin samples [1]
Eγ is the gamma-ray energy, PE 90◦ ∕ E the net count in the gamma ray peak divided by the full-energy-peak efficiency, IR the relative intensity of the gamma ray and ⟨ E 90◦ ⟩ the fast neutron spectrum averaged isotopic cross section for gamma ray production at angle of 90° between neutron beam and detector determined with Eq (2)

Summary

Introduction

Accurate non-destructive chemical analysis of materials is of fundamental importance in many fields of science and for industrial applications. The spectrum of the iron contains the most intense prompt gamma rays induced by the inelastic scattering of fast neutrons on the iron isotopes 54Fe, 56Fe, 57Fe and 58Fe. Gamma lines of 19F appear due to the sample packing made of Teflon.

Results

Conclusion