AUTONOMOUS ROBOTIC DETECTION OF RADIOISOTOPES BY HIGH PURITY GERMANIUM DETECTOR.

The use of High Purity Germanium (HPGE) detectors for identifying radio-isotopes with Gamma Ray Spectroscopy is well established. By analyzing the frequency of the incoming gamma radiation, it is possible to identify which isotope emitted it. There are several commercially available units capable of giving a human continuous updates to aid searching a room. However, the vast majority of these systems are dependent on the human user's ability to zero in on the location of the source. This project has integrated a commercially available HPGE system with a robotic base which is able to track its position within a room. The robot has been programmed to be able to automatically calculate the bearing of a radio-isotope source by slowly rotation on the spot and measuring the Q value calculated by ORTEC's isotope identification program. By recoding the Q value of every isotope on each bearing and analyzing the results in MATLAB, it is possible to calculate the peak and thus the direction of the source. The robot can then be remotely moved to another spot in the room to repeat the process. With three bearings to the source, this robot can then triangulate the position of the source and report this to the handler. The program is able to track multiple different sources at once, allowing for the whole room to be searched with only a few readings. This is the first time that isotope-specific data has been directly analyzed by a machine to find meaning full conclusions. With this step completed it is only a matter of extension to create an entirely autonomous robot, capable of searching a room and locating all sources to within a certain statistical certainty. During the process, some unexpected properties of the sensor have been found which will be explained in full in the paper. [ABSTRACT FROM AUTHOR]