The feasibility of boron containing phosphors in thermal neutron image plates, in particular the systems M2B5O9X : Eu2+ (M=Ca, Sr, Ba; X=Cl, Br). Part I: simulation of the energy deposition process

A thermal neutron image plate (IP) consisting of a mixture of BaFBr : Eu2+ and Gd2O3 (IP-Gd) is compared with an alternative plate consisting of M2B5O9X : Eu2+ (M=Ca, Sr, Ba; X=Cl,Br) (IP-B). In particular, the Detective Quantum Efficiency (DQE) of both plates is considered. Monte Carlo simulations of the energy deposition process after the absorption of a neutron show that the variance of the energy deposition in the IP-Gd affects the DQE to a large extent. Because of this, the average number of photoelectrons detected per incident neutron, 〈Nphe〉, has to be only 1.3 for the haloborates to obtain an IP-B with a higher DQE value than the maximum possible with a IP-Gd.