A DETECTOR FOR SUBMILLIMETER GAMMA-CAMERAS

Anger cameras (SPECT etc.) presently used in nuclear medicine employ a s active detector NaI crystals, obtaining intrinsic spatial resolution s greater than or equal to 3mm. Arrays made of optically isolated sing le crystal elements of YAP:Ce, having sub-millimeter aperture size, re ad out by position sensitive photomultipliers, allow to build active d etectors to employ in SPECT systems, with intrinsic spatial resolution below the millimeter, and with time resolution of the order of tens o f nanoseconds. In this paper preliminary results of measurements carri ed on different kinds of YAP:Ce arrays are reported. The measurements have been performed aiming to optimize the geometrical and physical pa rameters of the crystals in order to accomplish a SPEM (Single Photon Emission Mammography) camera detector.