Eye safety considerations of a laser-based rail flaw detection system Available to Purchase

The Transportation Technology Center, Inc. (TTCI), a subsidiary of the Association of American Railroads (AAR) and Tecnogamma, SPA are evaluating the efficacy of a non-contact, laser-based rail flaw detection system. Through the photo-acoustic effect, the absorption of nanosecond laser pulses by the rail results in the generation of both bulk and surface acoustic waves propagating within and on the rail respectively. The modifications of acoustic (ultrasonic) waves by the presence of rail flaws are detected by an array of ultrasonic air-coupled transducers and pattern recognition software. The concern for the eye safety of bystanders and system maintenance personnel in the proximity of this flaw detection system prompted a determination of the nominal hazard zone. The extent of the eye hazard resulting from the reflected laser radiation was determined by both analytical and empirical means and the results of this hazard evaluation, including a comparison of the computed and measurements results, will be presented.