Exposure of [formula omitted]-alanine and [formula omitted]-ammonium tartrate ESR dosimeters to thermal neutrons: Experiments and Monte Carlo simulations

Abstract

Electron spin resonance solid state dosimetry with alanine and ammonium tartrate pellets is a valuable tool in both medical and industrial applications when dealing with photon and charged particle beams. Its use in neutron beams is limited by the low nuclear cross section values of atoms in the pellets. Addition of boron ( 10B) or gadolinium ( Gd 2 O 3 ) , known to have high neutron capture cross sections, has been proposed to improve neutron sensitivity. In this paper we present the results of an experimental study concerning neutron sensitivity vs. gadolinium concentration in dosimeter mixtures, with the aim of optimizing mixture composition and maximizing the electron spin resolution (ESR) signal. For gadolinium concentrations up to about 25%, the dosimeter sensitivity increases with concentration. A saturation value is reached afterwards because of the smaller presence of the main ESR sensible compounds (i.e. alanine or ammonium tartrate). Monte Carlo techniques have been applied and comparisons between computational and experimental results have been carried out.