Laser safety considerations

Safety Considerations. High-power lasers raise a number of safety issues. There are the flammability and the toxicity of dye solutions. Most importantly, the eye hazards of laser radiation require careful shielding of the beam, and interlocks that restrict access to the laser room and to the dome. The laser could also dazzle aircraft pilots if they look directly down the beam. It is therefore necessary to close a shutter in the beam when a plane comes too close, either manually by human spotters, or automatically by use of radar, thermal IR or CCD cameras. Care must also be taken to avoid hitting overhead satellites in the case of pulsed or high power laser systems. 

S.D. Harvey, T.J. Peters and B.W. Wright, Safety considerations for sample analysis using a near-infrared (785 nm) Raman laser source, Appl. Spectrosc., 57, 580-587 (2003). 

Harvey, S.D. Peters, T.J. 8t Wright, B.W. Safety Considerations for Sample Analysis Using a Near-Infrared (785 nm) Raman Laser Source Appl. Spectrosc. 2003, 57, 580-587. 

There are several points to think about when considering an on-line trial. Some of these considerations are generic to all analyzers, but, in addition, there are some specific safety aspects about using a Raman analyzer. The generic questions revolve around the sampling interface integrity and the analyzer enclosure. These generic questions are outside the scope of this chapter, but further information can be found in Chapter 3. The Raman-specific questions resolve around three areas of laser safety, namely with respect to the sample, the process environment, and the operator. These three areas can be broken down further ... 

Choosing a suitable Raman spectrometer for on-line process analysis requires different criteria from laboratory analysis. Some key considerations are laser safety, ruggedness, repeatability, long-term and environmental stability, high uptime, calibration ttansferability, ease of operation and maintenance, smart diagnostics for analyser performance, and industry-standard communication. Many processes require the analysis to be performed... 

Lasers are commonly used in the laboratory, although in many instruments, most lasers are embedded in instrumentation and are therefore shielded or protected by optical barriers and interlocks that, when functioning properly, prevent accidental exposure. Care must be exercised when performing maintenance or when changing samples in such instruments. In this section we provide basic information on laser safety and hazards (Refs. 1 to 3). This is by no means exhaustive nor is it meant to substitute for an understanding of the specific safety requirements of instrumentation, or applicable law or regulations. The special case of common laser pointers has received considerable attention recently and is treated separately. We note that as of 2007, the general practice in the United States is to use the lEC definitions. 

Some of the safety considerations for laser safety include ... 

Safety mnst be the first consideration of any process analytical installation. Electrical and weather enclosures and safe instrnment-process interfaces are expected for any process spectroscopy installation. The presence of a powerfnl laser, however, is nniqne to process Raman instruments and mnst be addressed due to its potential to injnre someone. Eye and skin injnries are the most common resnlts of improper laser exposure. Fortunately, being safe also is easy. Becanse so many people have seen pictnres of large industrial cutting lasers in operation, this is often what operations personnel erroneonsly first envision when a laser installation is discnssed. However, modem instmments nse small footprint, comparatively low power lasers, safely isolated in a variety of enclosures and armed with various interlocks to prevent accidental exposnre to the beam. 

Escher, G., Weathers, J., and Labonville, B., Safety Design Considerations in Deep-UV Excimer Laser Photohthography, in Hazard Assessment and Control Technology in Semiconductor Manufacturing II, pp. 293—303, American Conference of Governmental Industrial Hygienists, Cincinnati, OH (1993)... 

Nevertheless, predictions are a valuable form of analysis that also provide insight into safety, maintenance and warranty costs and other product considerations. US Department of Defence Handbook (M1L-HDBK-217F, dd Dec 1991) can be used for reliability prediction of electronic components (e.g. microcircuits, semi-conductors, lasers, resistors, capacitors, etc.). The purpose of MlL-HDBK-217 is... 

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