Patent ID: 8143575

Claim:
A system for nuclear material detection inside an interrogated volume, comprising: at least a first flat muon detector and a second flat muon detector positioned above and below, respectively, the interrogated volume on the way of muons, the first muon detector is indicative of a first muon location and a first incidence angle, and the second muon detector is indicative of a second muon location and a second incidence angle, the DSP unit accumulates data on the second muon location and the second incidence angle; the DSP unit compares the actual muon deviation distribution and a reference deviation distribution from a database; wherein the deviation is the difference between the first angle and the second angle; the DSP unit make a decision on the presence or absence of the high Z material inside the interrogated volume if a correlation between the actual and the reference deviation distributions is below or above a predetermined value, respectively.