Position and energy resolution of a new gamma-ray detector based on a single CsI(Tl) scintillator coupled to a silicon drift chamber array

We have developed a first prototype of gamma-ray detector for imaging and spectroscopy which is based on a single CsI(Tl) scintillator coupled to a linear array of silicon drift chambers (SDCs). The detector performs the measurement of the position of interaction in one coordinate, by the centroid method, and the measurement of the γ photon energy, by summing the signals of all the single units. The small size and the compactness of the CsI(Tl)-SDC assembly make this detector scheme an interesting solution for the realization of small scintillation cameras for nuclear medicine. Moreover, the low electronics noise offered by the SDC allows to reach good performances in both position and energy resolution. The first experimental results obtained on the prototype are reported in this work. A position resolution better than 1 mm FWHM and an energy resolution of about 16% FWHM at 122 keV have been measured. A comparison of the experimental results with the results of Monte Carlo simulations is also reported