The comparison of five neutron sources via 7Li(p,n) reaction for the design of a facility based on prompt gamma ray neutron activation analysis (PGNAA) in vivo detections of boron

Abstract

Prompt Gamma Ray Neutron Activation Analysis (PGNAA) is a useful nondestructive method with numerous applications. In this study neutron yield from 7Li(p,n) reaction with proton energies of 2.5, 3, 4, 4.5 and 5 MeV was used in order to provide the necessary thermal beam to the investigated sample. The facility was designed and simulated using the MCNPX Monte Carlo code. The primary goal was the enhancement of the signal to noise ratio and the improvement of the detection limit of the system. An extensive series of simulations were performed for each source in order to examine the consequence of the solid angle which formed between the neutron beam and the collimator detector. Boron was used as an element which emits the prompt gamma rays and according to the simulations, 2.5 and 3 MeV protons beams offer the best performance, while for proton beam with energy in the range between 4-5 MeV the results indicate slightly poorer performance. Simulations are presented for the in-vivo PGNAA in the human liver.