Experimental tests of a radiation direction finder

We explore the possibility of using a simple detector to determine the direction or heading toward a source of nuclear radiation, typically penetrating neutrons or gamma rays. The technique is based on the attenuation of incident radiation across a scintillator that has been segmented so that differences between the count rates provide the orthogonal components of the local radiation vector. A number of simple measurements are carried out using plutonium, californium, and gamma-ray sources at distances of 1-20 m, with results that are in good agreement with earlier Monte Carlo predictions. In addition, triangulation allows the distance to the source to be estimated by correlating the observations from two or more detectors. These initial studies suggest that directional detectors may be useful in applications such as searching for nuclear materials or monitoring the location of radiation sources in storage vaults.