Patent ID: 7538325

Claim:
An inspection system for inspecting an object, the inspection system comprising: a) a first source of x-rays characterized, at any instant during which the first source is active, by a first instantaneous energy spectrum of penetrating radiation that is dominated by photons of energies less than or equal to a first fiducial energy, the x-rays for irradiating the object; b) a second source of pulsed penetrating radiation, distinct from the first source of x-rays, characterized, at different moments, by two distinct instantaneous spectra, (i) a second instantaneous spectrum dominated by photons of energies exceeding a second fiducial energy and less than a third fiducial energy; and (ii) a third instantaneous spectrum dominated by photons of energies exceeding a photo-nuclear reaction threshold; c) an x-ray detector for detecting x-rays of the first source and of the second source that are transmitted through or scattered by the object; d) a first conditional controller especially adapted to activate the second source in its second instantaneous spectrum only when x-rays of the first source fail to be transmitted through the object; e) a single-pulse switch for switching the second source between its second instantaneous spectrum and its third instantaneous spectrum; f) a second conditional controller especially adapted to activate the single-pulse switch, thereby switching the second source to its third instantaneous spectrum for the duration of a single pulse, only when photons of the second instantaneous spectrum fail to be transmitted through the object.