Patent attributes
The invention provides a device (100) for screening one or more items (101,1806) of freight or baggage for one or more types of target material, the device comprising: a source (200, 201,1800) of incident radiation (204,206,1804) configured to irradiate the one or more items (101,1806); a plurality of detectors (202,209,1807, 301) adapted to detect packets of radiation (205,207,1700) emanating from within or passing through the one or more items (101, 1806) as a result of the irradiation by the incident radiation (204, 206, 1804), each detector being configured to produce an electrical pulse (312) caused by the detected packets having a characteristic size or shape dependent on an energy of the packets; one or more digital processors (203, 210, 303, 304, 306, 305) configured to process each electrical pulse to determine the characteristic size or shape and to thereby generate a detector energy spectrum for each detector of the energies of the packets detected, and characterize a material associated with the one or more items based on the energy spectrum.
