Energy response and resolution of YAP:Ce matrix for imaging applications in nuclear medicine

In order to design an accurate imaging detector for Nuclear Medicine, the energy performances of several YAP:Ce crystal arrays were investigated upon. Indeed, the new multipillar configuration used for the crystal gamma detector, needs an attentive pillars dimensions study in order to optimize the light yield, the detection efficiency and the spatial linearity. At first, the YAP:Ce matrix were coupled with a EMI 9765 traditional phototube; measurements of light yield and energy linearity were taken by irradiating the crystals with Am-241, Ba-133 and Cs-137 point-like sources. Then, the energy response and resolution of a 40 mm x 40 mm detection area YAP:Ce matrix coupled with a Hamamatsu R2486 Position Sensitive PMT were attentively analyzed. Differences were found in the energy response on the whole detection area, but with an adequate equalization procedure it is possible to recover the response homogeneity as well as improving the detector energy resolution.