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Standardization of Broadband UV Measurements for 365 nm LED Sources



George P. Eppeldauer


Broadband UV measurements are analyzed when UV-A irradiance meters measure optical radiation from 365-nm sources. The CIE standardized rectangular-shape UV-A function can be realized only with large spectral mismatch errors. The spectral power-distribution of the 365-nm excitation source is not standardized. Accordingly, the readings, made with different types of UV meters, even if they measure the same UV source, can be very different. Commercially available UV detectors and UV meters were measured and evaluated for spectral responsivity. The spectral product of the source- distribution and the meter’s spectral-responsivity were calculated for different combinations to estimate broad-band signal-measurement errors. Standardization of both the UV source-distribution and the meter spectral-responsivity is recommended here to perform uniform broad-band measurements with low uncertainty. It is shown what spectral responsivity function(s) is needed for new and existing UV irradiance meters to perform low-uncertainty broad-band 365-nm measurements.
Journal of Research (NIST JRES) - 117.004
Report Number


365-nm source, broad-band measurement, CIE standard, spectral distribution, spectral responsivity, ultraviolet, UV-A, UV irradiance, UV-meter, UV source


Eppeldauer, G. (2012), Standardization of Broadband UV Measurements for 365 nm LED Sources, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed May 19, 2024)


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Created February 2, 2012, Updated November 10, 2018