Seibersdorf Laboratories

Seibersdorf, Austria

Seibersdorf Laboratories

Seibersdorf, Austria
SEARCH FILTERS
Time filter
Source Type

Lund B.J.,U.S. Army | Schulmeister K.,Seibersdorf Laboratories
Journal of Laser Applications | Year: 2013

The proposed revisions to the ANSI Z136, ICNIRP, and IEC 60825-1 laser exposure limits for multiple pulse ocular exposure for wavelengths from 400 to 1400 nm are examined for pulse durations t p ≥ t min (Ti). The three rules that are defined to be applied for multiple pulse exposures (or for classification for IEC 60825-1) are compared to identify criteria for which one of the rules is the critical one, i.e., the rule that limits the energy per pulse for a given exposure or product emission. Such a comparison can help to simplify a safety analysis, but also guide the design of systems for which the output is to be maximized yet still be classified as a Class 1 or Class 2 laser system. © 2013 Laser Institute of America.


Schmid G.,Seibersdorf Laboratories | Kuster N.,Foundation for Research on Information Technologies in Society ITIS | Kuster N.,ETH Zurich
Bioelectromagnetics | Year: 2015

The objective of this paper is to compare realistic maximum electromagnetic exposure of human tissues generated by mobile phones with electromagnetic exposures applied during in vitro experiments to assess potentially adverse effects of electromagnetic exposure in the radiofrequency range. We reviewed 80 in vitro studies published between 2002 and present that concern possible adverse effects of exposure to mobile phones operating in the 900 and 1800MHz bands. We found that the highest exposure level averaged over the cell medium that includes evaluated cells (monolayer or suspension) used in 51 of the 80 studies corresponds to 2W/kg or less, a level below the limit defined for the general public. That does not take into account any exposure non-uniformity. For comparison, we estimated, by numerical means using dipoles and a commercial mobile phone model, the maximum conservative exposure of superficial tissues from sources operated in the 900 and 1800MHz bands. The analysis demonstrated that exposure of skin, blood, and muscle tissues may well exceed 40W/kg at the cell level. Consequently, in vitro studies reporting minimal or no effects in response to maximum exposure of 2W/kg or less averaged over the cell media, which includes the cells, may be of only limited value for analyzing risk from realistic mobile phone exposure. We, therefore, recommend future in vitro experiments use specific absorption rate levels that reflect maximum exposures and that additional temperature control groups be included to account for sample heating. Bioelectromagnetics. 36:133-148, 2015. © 2015 Wiley Periodicals, Inc.


Schmid G.,Seibersdorf Laboratories | Hirtl R.,Seibersdorf Laboratories | Hirtl R.,Vienna University of Technology
Physics in Medicine and Biology | Year: 2016

The reference levels and maximum permissible exposure values for magnetic fields that are currently used have been derived from basic restrictions under the assumption of upright standing body models in a standard posture, i.e. with arms laterally down and without contact with metallic objects. Moreover, if anatomical modelling of the body was used at all, the skin was represented as a single homogeneous tissue layer. In the present paper we addressed the possible impacts of posture and skin modelling in scenarios of exposure to a 50 Hz uniform magnetic field on the in situ electric field strength in peripheral tissues, which must be limited in order to avoid peripheral nerve stimulation. We considered different body postures including situations where body parts form large induction loops (e.g. clasped hands) with skin-to-skin and skin-to-metal contact spots and compared the results obtained with a homogeneous single-layer skin model to results obtained with a more realistic two-layer skin representation consisting of a low-conductivity stratum corneum layer on top of a combined layer for the cellular epidermis and dermis. Our results clearly indicated that postures with loops formed of body parts may lead to substantially higher maximum values of induced in situ electric field strengths than in the case of standard postures due to a highly concentrated current density and in situ electric field strength in the skin-to-skin and skin-to-metal contact regions. With a homogeneous single-layer skin, as is used for even the most recent anatomical body models in exposure assessment, the in situ electric field strength may exceed the basic restrictions in such situations, even when the reference levels and maximum permissible exposure values are not exceeded. However, when using the more realistic two-layer skin model the obtained in situ electric field strengths were substantially lower and no violations of the basic restrictions occurred, which can be explained by the current-limiting effect of the low-conductivity stratum corneum layer. © 2016 Institute of Physics and Engineering in Medicine.


Schulmeister K.,Seibersdorf Laboratories
The World's Leading Conference on Laser Safety, ILSC 2011 - International Laser Safety Conference | Year: 2011

Laser products that emit continuous wave (cw) visible radiation with powers up to 5 mW have been widely used for pointing and alignment purposes for more than 30 years. Under IEC 60825-1 such lasers are classified as Class 3R. Experience shows that these lasers are quite safe for momentary accidental exposure, even though the exposure limit might be exceeded by up to a factor of 5. In this paper a case is made that this general experience of relative safety should not be extrapolated to pulsed emissions and extended sources without a more detailed quantitative risk analysis. Following the update of the exposure limits by ICN1RP, ANSI and IEC, the minimal safety factor of about 2.5 will apply to a much wider range of parameter combinations as compared to the current limits. For the case that Class 3R AEL values remain linked to the MPEs by a factor 5 in all cases, there will be many more products where an exposure can exceed the injury threshold even for momentary accidental exposure.


Schulmeister K.,Seibersdorf Laboratories
The World's Leading Conference on Laser Safety, ILSC 2011 - International Laser Safety Conference | Year: 2011

Based on recent research, the exposure limit for retinal thermal injury can be updated in terms of wavelength dependence, spot size dependence and basic time dependence. The update is to be published by ICNIRP, the International Commission on Non-Ionizing radiation protection in autumn 2011. In parallel, IEC 62471 and CIE S009 are to adopt their emission limits accordingly.


Kriz A.,Seibersdorf Laboratories
IEEE International Symposium on Electromagnetic Compatibility | Year: 2016

The EMC community is working towards shorter test distances for radiated emission measurements in the frequency range from 9 kHz to 30 MHz. This would reduce the cost for testing dramatically since typical absorber lined shielded rooms can be used for magnetic field strength measurements. The reduction of the test distance will lead to higher emission limits. In combination with pulsed signals commercially available active loop antennas are not suitable due to insufficient dynamic range. Measuring a 2 % duty cycle signal will increase the dynamic range by 30 dB. Pulsed signal have to be taken into consideration because pulse width modulation is one of the possibilities to control power in wireless charging applications. © 2016 IEEE.


Schulmeister K.,Seibersdorf Laboratories
The World's Leading Conference on Laser Safety, ILSC 2013 - International Laser Safety Conference | Year: 2013

The upcoming new edition of IEC 60825-1 allows to treat the light output which replaces traditional light sources by laser powered emissions, and that do not exceed a certain radiance, to be assessed under IEC 62471 (the lamp safety standard series). Since lamps (at distances where they can be hazardous) are all extended sources, the exposure and emission limits for the retina are specified in terms of radiance. Radiance has very attractive properties for extended sources, but is not intended to be applied to characterize point sources. During the discussion in the standard committee TC76, the level of radiance of a 1 mW laser pointer (which is known to be safe) was discussed. However, the calculation of radiance for safety purposes needs to consider a proper choice of source size and averaging due to the small beam diameter. The concept of radiance is discussed as applied to the sun, a 1 mW laser pointer and a laser illuminated phosphor, as well as the current and new exposure limit for broadband radiation.


Schulmeister K.,Seibersdorf Laboratories
The World's Leading Conference on Laser Safety, ILSC 2015 - International Laser Safety Conference, Conference Program and Proceedings | Year: 2015

Since Edition 2 of IEC 60825-1, the classification of I products such line lasers, scanners, DOE or others that produce an extended retinal image can be based either on a simplified analysis, assuming a small retinal • image, or on an extended analysis, where the angular 1 subtense of the apparent source needs to be I characterized as well as the classification needs to be ▪ based on the "most restrictive position". Even though ' this concept is standardized for almost 10 years, ] uncertainties in the application are frequent and ; discussion of the concept in the form of examples should be helpful. It is emphasized that in many eases, j there is not "one" apparent source associated to a given i product, and that further distances can be more | restrictive than closer distances, which is not \ intuitively known from conventional sources and is the j very reason for the special procedure defined in J IEC 60825-1.


Schmid G.,Seibersdorf Laboratories | Cecil S.,Seibersdorf Laboratories | Uberbacher R.,Seibersdorf Laboratories
Physics in Medicine and Biology | Year: 2013

Based on numerical computations using commercially available finite difference time domain code and a state-of-the art anatomical model of a 5-year old child, the influence of skin conductivity on the induced electric field strength inside the tissue for homogeneous front-to-back magnetic field exposure and homogeneous vertical electric field exposure was computed. Both ungrounded as well as grounded conditions of the body model were considered. For electric field strengths induced inside CNS tissue the impact of skin conductivity was found to be less than 15%. However, the results demonstrated that the use of skin conductivity values as obtainable from the most widely used data base of dielectric tissue properties and recommended by safety standards are not suitable for exposure assessment with respect to peripheral nerve tissue according to the ICNIRP 2010 guidelines in which the use of the induced electric field strengths inside the skin is suggested as a conservative surrogate for peripheral nerve exposure. This is due to the fact that the skin conductivity values derived from these data bases refer to the stratum corneum, the uppermost layer of the skin, which does not contain any nerve or receptor cells to be protected from stimulation effects. Using these skin conductivity values which are approximately a factor 250-500 lower than skin conductivity values used in studies on which the ICNIRP 2010 guidelines are based on, may lead to overestimations of the induced electric field strengths inside the skin by substantially more than a factor of 10. However, reliable conductivity data of deeper skin layers where nerve and preceptor cells are located is very limited. It is therefore recommended to include appropriate background information in the ICNIRP guidelines and the dielectric tissue property databases, and to put some emphasis on a detailed layer-specific characterization of skin conductivity in near future. © 2013 Institute of Physics and Engineering in Medicine.


Kriz A.,Seibersdorf Laboratories
2015 IEEE Symposium on Electromagnetic Compatibility and Signal Integrity, EMCSI 2015 | Year: 2015

The papers deals with the influence of the calibration jig to the impedance measurement result. The goal is to characterize two different designs of calibration jigs and to correct the LISN impedance accordingly. Without proper correction there is a large difference of the phase angle. It is found that the correction works properly. However the results are not without ambiguity, due to the lack of the definition of a measurand. Assumptions regarding a suitable calibration plane must be made for proper phase angle measurements. © 2015 IEEE.

Loading Seibersdorf Laboratories collaborators
Loading Seibersdorf Laboratories collaborators