APPARATUS FOR DETERMINING A DIRECTION TO A SOURCE OF RADIATION

摘要

An apparatus for determining a direction to a source of radiation, e.g. a gamma-ray or neutron source at a range of 100 m or more, is described. The apparatus is rotatable, e.g. about a vertical axis, and comprises a plurality of radiation shields and radiation detectors. The radiation shields are separated from one another by gaps to form an alternating series of radiation shields and gaps around a closed path within the plane of rotation for the apparatus. The radiation detectors are arranged to detect changes in radiation passing through gaps between the radiation shields as the apparatus is rotated. In providing a rotatable series of radiation shields and gaps with radiation detectors arranged to detect radiation passing through the gaps in this way, a radiation imager is provided that may be seen as being broadly based on coded mask techniques, but which is sensitive to radiation from all azimuths in its plane of rotation.