Abstract: A detection system is provided. In one embodiment a silicon Compton recoil electron detector uses the Compton double scatter technique with recoil electron tracking to detect medium energy gamma rays from 0.3 to 30 MeV. Two detector layers are required; a silicon microstrip hodoscope and a calorimeter. The incoming photon Compton scatters in the hodoscope. The second scatter layer is the calorimeter where the scattered gamma ray is totally absorbed. The recoil electron in the hodoscope is tracked through several detector planes until it stops. The x and y position signals from the first two planes of the electron track determine the direction of the recoil electron while the energy loss from all planes determines the energy of the recoil electron. In another embodiment of the invention, the Compton double scatter technique with recoil electron tracking is used to detect x-rays from 300 to 2,000 keV. This embodiment is useful for nondestructive, real time inspection of munition items.

Abstract: A multi-channel readout chip is provided in which each channel has an analog section and a digital section. Each channel of the readout chip employs low noise charge amplifiers with self trigger and calibration capabilities to provide timing information with better than 20 nanosecond precision. The trigger threshold can be adjusted to provide energy discrimination. The chip has a sparse readout function in which only the channels which have received signals greater than a preselected threshold value are readout, thus providing fast data acquisition capabilities.

Abstract: An apparatus and method for non-destructively detecting and identifying narcotics, explosives, and other forms of contraband concealed within a container or otherwise hidden from view. A radioactive source is used in conjunction with both neutron and gamma ray detector arrays. Depending upon the desired accuracy as well as the accessibility to all sides of the container, both back scattered and forward scattered radiation can be measured. Multiple detection systems mounted along different axes allow pseudo three dimensional images of the container in question as well as its contents to be produced.

Abstract: A portable device used for non-destructive detection of illicit narcotics, or other hydrogen or light element containing substances, includes a weak, self-contained, radioactive source of fast neutrons and a detector for detecting scattered thermal neutrons and gamma rays. The detector design allows it to detect hermetically sealed or unsealed packages of narcotics or other materials concealed behind compartment barriers. The detector can also be used to detect the identity or type of material by simultaneously using both the gamma ray flux and thermal neutrons flux.