| abstract |
Techniques, apparatus and systems for detecting particles such as muons and neutrons. In one implementation, a particle detection system is disclosed to employ a plurality of drift cells, which can be for example sealed gas-filled drift tubes, arranged on sides of a volume to be scanned to track incoming and outgoing charged particles, such as cosmic ray-produced muons. The drift cells can include a neutron sensitive medium, such as a partial pressure of neutron sensitive operating gas or a layer of neutron sensitive material disposed in the interior of the drift cells, to enable concurrent counting of neutrons. If necessary, the drift cells can be used to also detect gamma rays. The system can be employed to inspect occupied vehicles at border crossings for nuclear threat objects. |