Patent ID: 8137976

Claim:
A method of examining contents of an object, comprising: scanning at least a portion of an object by a first radiation beam generated by a first radiation source, at a first angle; detecting radiation interacting with the object at the first angle; comparing the detected radiation at the first angle to a first threshold based, at least in part, on a predetermined density, in a first comparison; scanning at least the portion of the object by a second radiation beam generated by a second radiation source different from the first radiation source, at a second angle different than the first angle; detecting radiation interacting with the object at the second angle; and comparing the detected radiation at the second angle to a second threshold based, at least in part, on the predetermined density, in a second comparison; if the detected radiation at the first angle and the detected radiation at the second angle are both indicative of the at least potential presence of nuclear material, determining that the object at least potentially contains nuclear material based, at least in part, on the first and second comparisons.