Modeling and Implementation of an Automated Gamma Radiography Inspection System with Robotic Positioning and Bidimensional Radiative Mapping in Cartesian Coordinates

Abstract

This work presents the engineering architecture and controlled radiometric evaluation of a gamma-ray inspection system conceived for Cartesian X-Y automation in non-destructive testing of metallic plates. The architecture combines a Cadmium Zinc Telluride (CZT) detector, a collimated Cesium-137 source, lead shielding, Cartesian positioning, and computational mapping. The radiometric dataset reported here was acquired before complete motion integration: the source and detector remained fixed while aluminum plates of nominal 200 x 200 mm and 1 mm or 2 mm thickness were manually repositioned over a 4 x 4 grid. Three consecutive count-rate readings were averaged at each of the sixteen points and corrected using the recorded point-specific background. The resulting net count rates were associated with Cartesian coordinates and displayed as non-interpolated two-dimensional maps. Net count rates ranged from 1206.00 to 2213.67 cps for the 1 mm specimen and from 1538.00 to 2264.67 cps for the 2 mm specimen. Within each specimen, grouped values increased with the inferred open-hole condition; however, the two thickness series were non-monotonic and cannot be interpreted as an isolated thickness effect. For 662 keV photons in aluminum, the ideal narrow-beam Beer-Lambert model predicts transmissions of approximately 98.0% and 96.1% for 1 mm and 2 mm, respectively. Because a no-sample reference and complete pointwise uncertainty data were not available, absolute thickness, detection limit, and statistical significance were not claimed. The study therefore validates the acquisition-background-coordinate-mapping workflow and defines the metrological requirements for subsequent validation of the fully automated platform.