Hideki Tomita

A prototype system based on a combination of 4π sensitive gamma imaging and simultaneous localization and mapping (SLAM) was developed to find unknown radiation source(s) rapidly. The system consisted of a spherical visible camera, a three-dimensional light detection and ranging, a CdTe pixel array detector for 4π gamma imaging, a portable battery, and a control laptop personal computer; these were mounted on an unmanned vehicle. In a search area of 16 × 16 m 2 with a height of 3 m, the prototype system successfully demonstrated the finding of a 137 Cs point source with an activity of 0.67 MBq in the surrounding thin walls.