Operating Characteristics of Small Position-Sensitive Mercuric Iodide Detectors

Room temperature semiconductors are potentially attractive candidates for gamma cameras because of their compactness and high spatial resolution. We have evaluated position-sensitive HgI2 detectors for use in high resolution small area gamma cameras. Two 0.5 mm thick detectors resolved by orthogonal strips into elements 1.75 mm on a side and 0.9 mm on a side have been tested. The spatial resolution is 2 mm FWO.1M and 1 mm FWO.1M respectively. Energy resolution is improved by measuring energy from the anode in coincidence with the cathode signal of the detector. An energy resolution of 6.8 keV FWHM at 122 keV and 5.7 keV FWHM at 60 keV has been observed.