Patent ID: 7652254

Claim:
A system for nuclear material detection, comprising: a shielding layer adapted to allow muons, passing through the shielding layer while cutting off all other charged particles, at least a first flat muon detector and a second flat muon detector positioned along the way of muons passed through the shielding layer, the first muon detector is indicative of a first muon coordinate and a first incidence angle, and the second muon detector is indicative of an actual second muon coordinate and an actual second incidence angle, a digital signal processing unit for calculating a predicted second coordinate and a predicted second incidence angle, an alarm system being adapted for generating an alarm when a presence of a nuclear material between the first and the second flat muon detectors is suspected, wherein the digital signal processing unit compares the actual second muon coordinate and the actual second incidence angle with the predicted second coordinate and the predicted second incidence angle for each muon, and the presence of the nuclear material between the first and the second flat muon detectors is suspected if a difference between the actual second incidence angle and the predicted second incidence angle is larger than a predetermined value, further comprising a density of a substance between the first and the second detector changing in time, when the nuclear material is in a vehicle moving along the detectors with a speed V, wherein the detectors size assures measurement of at least one muon trajectory in each square of 100 cm 2 of the vehicle.