Novel materials and concepts for neutron image plates

Neutron image plates (NIPs) are used for two-dimensional, position-sensitive detection of neutrons. Commercially available neutron image plates consist of a mixture Gd2O3 and BaFBr:Eu2+. In this contribution we present a system of converter (6LiF) and storage phosphor (KCl:Eu2+), which exhibits a high efficiency for the detection of neutrons, while at the same time features a low γ-sensitivity due to the low atomic numbers. Two different morphologies of image plates based on KCl:Eu2+–6LiF were fabricated: ceramic (C-NIPs) and pixelated NIP (Pix-NIPs) . For these NIPs a neutron equivalent of 1/20 neutron per photon for soft γ-rays was found while the equivalent for hard γ-quanta is 1/400 neutron per absorbed photon. The detective quantum efficiency (DQE) of a C-NIP consisting of KCl:Eu2+–6LiF amounts to 38%, a value which is comparable to commercially available neutron image plates. Ps represent a novel structure in which the scattered light is confined to square cells embedded in the image plate. Due to this light confinement, the resolution of such an image plate is primarily independent of scattering properties of the NIP and is mainly a function of the size of the cell structure used.