Small prototype of Anger camera with submillimeter position resolution

In this work we present a small prototype of Anger camera based on a monolithic array of silicon drift detectors (SDDs) used as photodetectors for a single CsI(Tl) scintillator crystal. This prototype, having a total sensitive area of about 1 cm 2 , has been realized in order to evaluate the performances attainable in γ -ray imaging by using a SDD array instead of the more conventionally employed photomultiplier tubes. An intrinsic resolution better than 200 μ m has been measured with this camera. This result was achieved thanks to the extremely low electronics noise presented by the SDD units, fully exploited by the integration of the front-end junction field effect transistor directly on the detector chip. The main features of the detector as well as the results of its extended experimental characterization with 60 and 122 keV gamma rays are presented and discussed in the article. The present device has many potential applications in the field of medical imaging, in which outstanding position resolutions are essential.