An improved maximum permissible exposure meter for safety assessments of laser radiation

• Published in: Optics and lasers in engineering Vol. 28; no. 6; pp. 423 - 442
• Main Authors: Corder, D.A., Evans, D.R., Tyrer, J.R.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1997; Elsevier
• Subjects: Exact sciences and technology; General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Physics; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; Pyroelectric detectors; Radiation detectors; Visible radiation; Silicon; Safety; Experimental study; Laser beams; Photodiodes; Thermopiles
• ISSN: 0143-8166; 1873-0302
• DOI: 10.1016/S0143-8166(97)00055-9

Current interest in laser radiation safety requires demonstration that a laser system has been designed to prevent exposure to levels of laser radiation exceeding the Maximum Permissible Exposure. In some simple systems it is possible to prove this by calculation, but in most cases it is preferable to confirm calculated results with a measurement. This measurement may be made with commercially available equipment, but there are limitations with this approach. A custom designed instrument is presented in which the full range of measurement issues have been addressed. Important features of the instrument are the design and optimisation of detector heads for the measurement task, and consideration of user interface requirements. Three designs for detector head are presented, these cover the majority of common laser types. Detector heads are designed to optimise the performance of relatively low cost detector elements for this measurement task. The three detector head designs are suitable for interfacing to photodiodes, low power thermopiles and pyroelectric detectors.
Design of the user interface was an important aspect of the work. A user interface which is designed for the specific application minimises the risk of user error or misinterpretation of the measurement results. A palmtop computer was used to provide an advanced user interface. User requirements were considered in order that the final implement was well matched to the task of laser radiation hazard audits.