A 4-π field of view Compton imager based on a single planar germanium detector

A Compton imager has been developed based on a single germanium strip detector. The system has the ability to image point or continuous gamma ray sources located anywhere in a 4-π field of view. The effective energy range for imaging is approximately 200 keV to greater than 1 MeV. The system was designed as a prototype for a field deployable system. Therefore, custom electronics were designed and other efforts were made such that the entire system could fit on a small lab cart and be moved by a single person. Possible applications include search and monitoring of radionuclide material. Various images are shown and the ability of the imager to find a source in the presence of high background is demonstrated. The absolute imaging efficiency or the detector at 511 keV is shown to be ∼ 4 * 10^-3 for this system. Of events that deposited their full energy in the detector, it is shown that ∼20% are suitable for imaging using current techniques. Methods to improve the efficiency in future systems are discussed.