Locating the positions of reinforcing bars in reinforced concrete using backscattered gamma rays

Survey of industrial, agricultural, and medical applications of radiometric gauging and process control

“…Henderson and McGhee [ 84 , 85 ] have mathematically modelled a gamma-ray backscattering (albedo) gauge using 137 Cs (0.66 MeV) or 60 Co (1.17, 1.33 MeV) sealed “not too powerful” (e.g., 74 MBq) radiation sources for probing near-surface rock and soil densities without the need of the boreholes required in transmission gauging. For examining concrete walls in existing buildings, particularly for the presence, quantity, size, and position of steel reinforcing bars (rebar), and also for voids, Hussein and Whynot [ 86 ] and Tuzi and Sato [ 87 ] have demonstrated and described Compton-scattering gamma-ray single-scatter albedo probes. Such probes examine the small volume which is the common volume of intersection of the projections of the source collimator and the detector collimator, axially intersecting inside the concrete wall material, which volume can then be characterized by its density and other gamma-ray Compton scattering properties.…”

Quantification of gamma-ray Compton-scatter nondestructive testing

“…A basic inspection system, used by many workers (Berodias and Peix, 1988;Whynot and Hussein, 1989;Tuzi and Sato, 1990;arnong others), is depicted in Figure 1.1. The intersection of a collimated beam of photons with a collimated field of view of a detector defines the inspection (scattering) volume.…”