Statistical description of response to flood-field irradiation in scintillation crystal arrays

Images obtained by flood-field Co57 irradiation of CsI(Tl) crystal arrays detectors, coupled to a metal-channel dynode PSPMT, were statistically analyzed by means of a bivariate normal distribution. For each crystal position, the planar distribution charge was described by a confidence ellipse chosen to maximize the 1-to-1 relationship between the photons incoming at each crystal and the centroid obtained from electric charge distribution. The flood-field irradiation response of a 22 mm×22 mm CsI(Tl) array, with different pixel dimensions, were studied, and the comparison between the charge distribution of a limited number of crystals following the flood-field irradiation was made.