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Detailed comparisons of the spectral irradiance of the NBS Synchrotron Ultraviolet Radiation Facility II and tungsten FEL Scale of Spectral Irradiance at 297 and 254 nm with an uncertainty of ~1% show that these irradiance standards are consistent at both wavelengths to within the uncertainties assigned to them by NBS.
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Kostkowski et al. (1986) studied this question.
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