A method and system for high Z substance revealing using muon detection technique is presented. Natural muon coordinate and incidence angle are measured above and below the interrogated volume. The data on muons trajectory change caused by the presence of high Z material and the muons time of flight between the upper and lower muon detectors are used for the decision making on the presence of a nuclear substance inside the volume. The system is adapted for performing measurements on moving objects such as moving trucks.
