A high efficiency fast-response gamma detector with mrad pointing capabilities

A High Efficiency fast-Response GAmma detector (HERGA) for the identification of radionuclides and for gamma-ray imaging is presented. The detector is compact, ideal for real-time analysis, with low power consumption, suitable for industrial process control, environmental monitoring and localization of nuclear wastes. A prototype consisting of 16 CsI(Tl) scintillators coupled to photomultiplier tubes (PMTs) with a digital readout was built. The scintillators are arranged in a 4 × 4 matrix; a 7 × 7 mask composed by plastic and tungsten tiles has been used to validate the imaging figures of merit according to coded mask principle. A 2D Kolmogorov–Smirnov pattern recognition statistical method has been developed, allowing to achieve a point spread function (PSF) of a few mrad for pointlike sources. The Minimum Detectable Activity (MDA) was also determined in the case of pointlike radioactive sources.