⁶LiF:ZnS(Ag) Mixture Optimization for a Miniature Highly Efficient Cold Neutron Detector

Abstract

We report the optimization of a ^6^LiF:ZnS(Ag) scintillator mixture for an ultrathin (~2nm), highly efficient cold neutron dector. Preliminary results with early protypes demonstrate excellent for 3.62 meV (4.75 Angstrom wavelenght) neutrons but mediocre neutron sensitivity (~30%). Our optimization took the form of selecting the appropriate phosphor stoichiometry, to ensure high neutron capture probability and good light transport within the scintillator medium, properties which deterime the total detection efficiency. We have characterized different ^6^LiF:ZnS(Ag): Binder mixture for light yield, neutron capture probability, and light transmission properties. We have determined the optimal configuration for our requirements of millimeter thickness and cold neutron energy. Optimized protypes exhibit excellent absorption and demonstrate neutron sensitivites of above 85% for 3.27 meV neutrons and gamma ray rejection ratios approcahing 1o^-17.