On the potential of photon induced annihilation photons for inspection of engineering structures

Backstreaming annihilation photons induced in matter via electron-positron pair production by high energy photons could be used for in situ inspection of engineering structures. The pair production cross-section increases with photon energy and is proportional to Z2 so it is suited to locating high-Z inclusions in lower-Z matrices. Monte Carlo simulation with the EGS4 code is used to illustrate the potential of annihilation photons for inspecting the position and condition of rebars inside steel reinforced concrete.