Product Code: ILSC2007_1405

Eye Safety Considerations of a Laser-Based Rail Flaw Detection System
Authors:
Fabrizio Prior, Technogamma, SPA; 31050 Morgano (TV) Italy
Gregory Garcia, Transportation Technology Center, Inc.; Pueblo, CO USA
Richard Hughes, High-Rez Diagnostics, Inc.; Camino CA USA
Presented at ILSC 2007

The Transportation Technology Center, Inc. (TTCI), USA and Tecnogamma SPA, Italy, have developed a prototype laser-based ultrasonic inspection system, identified as the U-Rail system, for non-contact rail inspection. 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 these acoustic (ultrasonic) waves by the presence of rail flaws, e.g., cracks, is detected by an array of ultrasonic 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.