Low-rate inexpensive digital γ-ray imaging/inspection system

A system configured for permanent installation in spatial relationship to a pipe for monitoring a section of the pipe over a long time, said system comprising:

• a unitary imaging assembly that includes:
• a stationary hollow cylindrical gantry configured to surround said section of the pipe;
• a γ-ray scanner comprising a Solid-State Single-Photon Detector (“SSSPD”) and a γ-ray source that is a radioisotope having an α-activity of about 35 kBq or less;
• an armature that fixedly supports the γ-ray source and the SSSPD in mutual opposed alignment, so that they are constrained to move together;
• said armature being configured to ride around an inside periphery of the gantry and the armature or the gantry being configured to move laterally in a direction parallel to a rotation axis of the armature so as to move the γ-ray beam and the SSSPD around and along the pipe at a sufficiently slow rate that completely exposes the section of pipe to the γ-ray source and thus produces a complete image of said section.