Gamma-ray source location by attenuation measurements

A method has been proposed to locate a point source by measuring the first moment of the count distribution in a 3D position-sensitive radiation detector. Measurements were performed using a HgI
2
crystal. A gamma source at 662 keV could be located to within a quadrant after fewer than 100 events due to the high atomic number of the detector. The performance of the method is studied through simulations and measurements. The method performs well even when few spatial bins are available. The presence of a thick inactive layer around the crystal degrades performance.