Lauer O.,ETH Zurich |
Benedickter H.,ETH Zurich |
Neubauer G.,Seibersdorf Labor GmbH |
Roosli M.,University of Basel |
Frohlich J.,ETH Zurich
2010 Asia-Pacific Symposium on Electromagnetic Compatibility, APEMC 2010 | Year: 2010
In this paper a calibration measurement setup for band-selective personal exposure meters is presented. The equipment and the methods of the measurement procedure are described together with the uncertainty assessment of the measurement equipment, the calibration and the measurement procedure. The average measurement error for the reference measurement is ± 0.32 dB, while the expanded uncertainty with a confidence interval of 95% is calculated to 2.5 dB. Furthermore a straight forward calibration method is described and tested using the EME SPY 120 device from Antenessa. Up to seven different measurements must be performed for a full characterization of personal exposure meters. The presented measurement setup leads to a higher accuracy of the calibration and the achieved results will allow for an improved exposure assessment in experimental and epidemiological studies. © 2010 IEEE.
Schulmeister K.,Seibersdorf Labor GmbH |
Stuck B.E.,U.S. Army |
Lund D.J.,U.S. Army |
Sliney D.H.,Consulting Medical Biophysicist
Health Physics | Year: 2011
Exposure limits (ELs) for laser and optical broadband radiation that are derived to protect the retina from adverse thermally-induced effects vary as a function of wavelength, exposure duration, and retinal irradiance diameter (spot size) expressed as the angular subtense α. A review of ex vivo injury threshold data shows that, in the ns regime, the microcavitation-induced damage mechanism results in retinal injury thresholds below thermal denaturation-induced thresholds. This appears to be the reason that the injury thresholds for retinal spot sizes of about 80 μm (α = 6 mrad) and pulse durations of about 5 ns in the green wavelength range are very close to current ELs, calling for a reduction of the EL in the ns regime. The ELs, expressed in terms of retinal radiant exposure or radiance dose, currently exhibit a 1/α dependence up to a retinal spot size of 100 mrad, referred to as referred to asmax. For referred to as & αmax, the EL is a constant retinal radiant exposure (no α dependence) for any given exposure duration. Recent ex vivo, computer model, and non-human primate in vivo threshold data provide a more complete assessment of the retinal irradiance diameter dependence for a wide range of exposure durations. The transition of the 1/α dependence to a constant retinal radiant exposure (or constant radiance dose) is not a constant αmax but varies as a function of the exposure duration. The value of αmax of 100 mrad reflects the spot size dependence of the injury thresholds only for longer duration exposures. The injury threshold data suggest that αmax could increase as a function of the exposure duration, starting in the range of 5 mrad in the μs regime, which would increase the EL for pulsed exposure and extended sources by up to a factor of 20, while still assuring an appropriate reduction factor between the injury threshold and the exposure limit. Copyright © 2011 Health Physics Society.