Photo-neutron detection using Cr-39 solid state nuclear track detector

Abstract

Photo-neutrons are produced when high energy x-rays interact with various elements by the (ɤ,n) reaction. The production is dependent upon the cross section and binding energy for the (ɤ,n) reaction to occur. The threshold energy required to overcome the binding energy for the production of photo-neutrons is different for different elements. Compared to the direct emission process, most of the photo-neutrons are produced by the evaporation process following resonance in heavy nuclei. Evaporation neutrons are emitted isotropically and have a broad range of energies. In this work, photo-neutron production from lead (Pb) and copper (Cu) were analyzed using CR-39 SSNTD. The 15 MV bremstrahlung x-rays from a Siemens Primus Plus medical linear accelerator was used as the photon source. The passive method developed for the determination of the photo-neutron spectrum from various elements gives comparable results with the theoretical predictions.