OPTIMIZATION OF LIGHT OUTPUT FROM ZINC-SULFIDE SCINTILLATORS FOR FAST-NEUTRON RADIOGRAPHY

Fast neutron radiography (FNA) is a promising new application for smal l accelerators. The potential effectiveness of this technique depends on the development of suitable imaging detectors for fast neutrons. Zi nc sulphide based scintillators have the largest light output per even t in the family of imaging scintillators used so far in fast neutron r adiography. but zinc sulphide is not transparent to its own light. Thi s paper investigates different aspects of this scintillator in order t o establish the factors affecting the light output, Zinc sulphide scre ens were prepared by suspending ZnS(Ag) particles at different concent ration in a hydrogen rich matrix. The light output of these scintillat ors have been tested in fast neutron fields generated by the Li-7(p,n) Be-7 and D(d,n)He-3 reactions. The light output was detected using a C CD camera coupled to the scintillator screen by an optical fiber throu gh an image intensifier. The results are presented in the form of grap hs for different sets of particle sizes and concentrations. A comparis on has been made with a simple theoretical model. (C) 1998 Elsevier Sc ience B.V.