Backscatter Radiography for Crosstie Inspection and Evaluation of Scanning through Tie Plates

Backscatter radiography, a form of x-ray inspection, has been used for better detection of flaws and degradation in the inspection of crossties. The method utilizes the portion of photons that scatter off the target object back towards the source. Current systems detect flaws and degradation in wood crossties but have been limited to the area of the tie between the rails. To advance the technology, this investigation seeks to evaluate the portion of the tie underneath the tie plate where x-ray attenuation severely impacts the image quality and penetration depth of the photons. Laboratory experiments were conducted to simulate scanning through tie plate materials. Scanning through the tie plate material is the best-case scenario for adapting current practices. Results show that backscatter radiography is an effective non-destructive testing method for crosstie evaluation and scanning through a tie plate is possible, but limitations exist with regards to fidelity and image resolution.