High energy X-ray inspection system using a fan-shaped beam and collimated backscatter detectors

A scanning method for scanning an object in a scanning zone, the method comprising:

• irradiating the object with an X-ray radiation source having a peak energy of at least 900 keV, wherein the object is irradiated over a plurality of regions to be scanned within a single irradiation event;
• detecting X-ray radiation scattered from the object wherein said scattered X-ray radiation is detected from a predefined part of the scanning zone via a detector having a plurality of detector elements and wherein each detector element comprises a first photodetector, a second photodetector, and scintillator material positioned therebetween;
• determining a point of interaction between photons of said X-ray radiation and said plurality of detector elements by obtaining a first output from the first photodetector and a second output from the second photodetector, and determining a ratio of said first and second outputs;
• determining a pattern of detector exposures, wherein said pattern of detector exposures is created using a mask to create exposure patterns across multiple detection elements, said mask restricting scattered X-ray radiation that is not from a corresponding part of the scanning zone from reaching its corresponding detector region;
• and
• analyzing the pattern of detector exposures to allocate each exposure pattern with a particular radiation source position.