A lighthouse radiation detector is named for its sweeping and scanning field of view, which comes from all but one side being shielded, in this case with tungsten plates, to attenuate the detection of gamma rays. The location of a radiation source is determined by comparing the changing signal strength as the detector pivots, “looking” around the room. It can also distinguish between sources when multiple sources are present, offering improvements to both safety and speed of material inventories, geological surveys, or radiological remediation. It has been mounted on a HAZMAT robot to demonstrate how quickly large areas can be surveyed without sending in any people.