Abstract: A device for linear detection of radiation includes at least one thin plate (2) of a dense scintillating material, placed parallel to the direction of the beam of the radiation, the beam penetrating the plate by its edge beam, the plate having a sufficient depth in the direction of the beam to stop the major part of the radiation which has penetrated there, and at least one group of fluorescent optical fibers (4), which can be excited by the visible light emitted by the material under the impact of the radiation, these fibers having portions (6) which are parallel, adjacent and attached to one of the two faces of the plate so that these portions are parallel to the direction of the beam, thus making possible locating, along the edge of the plate, the impact of the particles of the radiation. The device has applications in medical imagery and in parts and luggage inspection.