Characterization and Calibration of UV Radiometers

2017-03-29

Finally a Method for the Characterization and Calibration of UV Radiometers

Press Release, Gigahertz-Optik Inc., 29 March 2017:

 

After eighteen years in the works CIE Technical Committee TC 2-47 has completed and published CIE 220:2016. [1] This technical report describes quality indices for UV radiometers, which enable manufacturers and users to characterize instruments on a common basis. To harmonize CIE documents, the quality indices described in this document relate to the quality indices described in Joint ISO/CIE International Standard ISO/CIE 19476:2014(E) (formerly CIE S 023/E:2013).

 

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BN-LH250 Calibration Standard Lamp

The work began in the First Workshop of the "Thematic Network for Ultraviolet Measurements" in Espoo, March 2 and 3, 1998. The Network was funded by the Standards, Measurements and Testing programme of the Commission of the European Communities, as project number SMT4-PL96-9329.
Within the Working Group 1 "Guidance for UV power meter classification for particular applications" with chair Anton Gugg-Helminger the document "Characterizing the Performance of Integral Measuring UV-Meters" was prepared. It is published in the UV news Issue 6/November2000. [2]
This publication was then adopted by CIE technical committee TC2-47 finishing the report in 2016.
Since UV filter radiometers very often measure light sources which are spectrally different than the light sources with which they were calibrated. As a result an uncertainty occurs called spectral mismatch error, defined as the ratio of the effective responsivity of the radiometer with respect to the radiant quantity of the test source to the effective responsivity with respect to the reference source.
UV radiometers in general are designed for various actinic spectra and different spectral ranges. So instead of only one defined reference light source spectra, CIE Illuminant A, used in photometry, three reference light source spectra are proposed in CIE 220 to support the generic spectral characterization of UV radiometers for various applications. For situations where three spectra are not sufficient for evaluating the spectral mismatch ten other light source spectra are provided in the UV News Issue 6/November2000 [2].
The report includes an explanation and methods for evaluating and correcting for spectral mismatch error assuming specific spectral responses are known. When detailed technical specifications are provided by the UV filter radiometer manufacturer, CIE 220:2016 information and methods can be employed to compare different meters.
Also included in the report:
Example evaluation of a UV-A radiometer designed for UV hazard assessment per ICNIRP/ACGIH guidelines
  • Short and long wavelength range response characteristics of UV radiometers and the impact on measurement results are explained
  • Recommendations for UV radiometer data sheet content and specifications
  • Uncertainty evaluation discussion including a list of major sources of uncertainty for UV radiometer calibration
References for CIE 220:2016
[1] CIE 220:2016 "Characterization and Calibration Method of UV Radiometers"
[2] UV news Issue6/November2000 Part A: Final report of WG1
[3] ICNIRP (International Commission on Non-Ionizing Radiation Protection) Sliney DH, Cesarini JP, De Gruijl FR, Diffey B, Hietanen M, Mainster M, Okuno T, Soderberg PG, Stuck B, eds. Guidelines on limits of exposure to ultraviolet radiation of wavelengths between 180 nm and 400 nm (incoherent optical radiation). Health Phys 87:171-186; 2004
[4] ACGIH (American Conference of Governmental Industrial Hygienists) 1992-1993 Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices ISBN: 0-936712-99-6
Gigahertz-Optik is a world class manufacturer of innovative UV-VIS-NIR optical radiation measurement instrumentation for specification critical industrial, medical and research applications.