Vacuum ultraviolet radiation scales: an accurate comparison between plasma blackbody lines and synchrotron radiation

Blackbody limited lines of C and N from an argon wali-stabilized arc have been used to determine the spectral radiance of specially developed deuterium discharge lamps at 165.7 nm, 167.0 nm, 174.3 nm, and 193.1 nm, following the attainment of significantly increased accuracy in plasma temperature determination. Comparison with calibrations based on the use of synchrotron radiation has shown agreement to within typically 1.5%, as the result of extensive studies of sources of systematic error. The agreement is well within the estimated uncertainties, which range from +/-3.7% at 165.7 nm to +/-2.7% at 193.1 nm for both techniques.