Abstract: The present invention provides a radiation detector arrangement wherein the detecting faces of the detecting elements are arranged at an acute angle to the plane of radiation, i.e., the plane parallel to the direction of relative movement between the radiation detector and the radiation to be detected. The remaining portions of the detector elements are shielded from receiving radiation from the source, by, for example, adjacent detecting elements or layers of high Z materials. As a consequence, the individual detector elements are sensitive to their position with respect to the radiation source, without the necessity of employing collimators. In a preferred embodiment of the invention, the individual detector elements are wedge-shaped, and are arranged in groups of four to define detectors having pyramidal recesses. In further embodiments of the invention, four detecting elements may be arranged in a back-to-back relationship, in the array, to form pyramidal detectors.

Abstract: Apparatus for detecting the location of a source of electromagnetic radiation is provided which does not employ a collimator. The need for a collimator is eliminated by the provision of a novel array of scintillators. The array comprises superposed scintillator crystals of three respective different types in their response to electromagnetic radiation. Three crystals of a first type are alternated with one crystal each of second and third types. An edge of each of the crystals is exposed at two opposed sides of the array. A first of the opposed sides is adapted to face a photomultiplier tube and the other of the opposed sidesis adapted to receive radiation from a source which is to be detected. The respective edges of the second and third types of crystals at the radiation receiving side of the array are in a first plane and the respective edges of the first type of crystals at the radiation receiving side of the array are in a second plane spaced from the first plane.