High-resolution gamma backscatter imaging for technical applications

A γ-ray imaging method is described which is suitable for non-destructive and non-invasive determination of amount and distribution of matter in objects. A point-like positron source is placed in front of the object to be examined. A position detector behind the source measuring 511 keV γ-rays from positron annihilation determines the direction of the correlated 511 keV γ-rays used to probe the object. Detecting the probing γ-ray after transmission through or scattering off the object in time coincidence to the position determining γ-ray enables to map the thickness and density distribution of the object. The method and system can be employed for security inspection of concealed items, control of erosion, deposition and structural defects, and the detection of land mines.