1. A system for a high Z material detection, comprising: at least a first muon detector and a second muon detector, the first muon detector is indicative of an incidence angle, and the second muon detector is indicative of an actual leaving angle for each muon passing the system; a muon velocity measurement unit, measuring a velocity for each incoming muon, a digital signal processing unit for storing a data on the incidence, the actual leaving angle and the velocity for muons passing the system during an exposure time T; calculating an actual statistics of the actual leaving angles being dependent on the muon velocity and an expected statistics of expected leaving angles, wherein the expected statistics of the expected leaving angle is estimated assuming absence of the high Z material in between the first and the second muon detector; finding a difference between the actual and the expected statistics; and determining a presence of the high Z material inside the system when the difference is above a predetermined difference value.