Ce-doped Gd${}_{3}$Al${}_{2}$Ga${}_{3}$O${}_{12}$ scintillator for compact, effective and high time resolution detector of the fast neutrons

Abstract

Gadolinium-aluminum-gallium garnet Gd${}_{3}$Al${}_{2}$Ga${}_{3}$O${}_{12}$:Ce scintillator is demonstrated to be an excellent scintillation material for detector of fast neutrons for the first time. Moreover, its application allows to obtain different responses to neutrons depending on their energy spectrum. This is achieved because the material, firstly, has high content of Gd, which absorbs neutrons with following emission of $γ$-quanta, and, secondly, detects this radiation efficiently thanks to high stopping power, fast scintillation kinetics, high scintillation light yield and good energy resolution. It was shown by simulation that several characteristic regions could be distinguished in $γ$-quanta pulse height spectra acquired with GAGG:Ce crystal under neutron irradiation, with energies nearly 90 and 190, and 511 keV; all these lines have different relative intensities depending on incident neutrons kinetic energy. This was confirmed by followed measurements with Am-Be neutron source. Scintillator shows coincidence time resolution better than 200ps for$γ$-quanta of 511 keV energy, what makes it the material of choice to separate neutrons by time-of-flight technique. Combining of detecting properties creates prospects to construct compact and fast neutron detector, capable of detection of each particle individually and registration of its specific response. This possibility could bring benefits to neutron-based examination techniques, e.g. utilizing time of flight methods and new capabilities of accelerator based bright neutron sources.