title: Nanosecond high radiance standard source.
abstract: Spectral radiances R(lambda) and luminances B in the center axis of high density 8-20-nsec spark channels as produced by Nanolite sources were systematically studied by comparison with the emission from a calibrated dc-carbon arc. The maximum value of R(lambda) was 53 W cm(-2) A(-1) sr(-1) in 1 atm of air at 4850 A with a breakdown voltage of 2.5 kV when the Nanolite (C = 2.9 nF, L = 2 nH) was charged slowly. This value increased to over 70 W cm(-2) A(-1) sr(-1) when the source was pulse charged. Saturation values of R(lambda) were 38 W cm(-2) A(-1) sr(-1) in 3 atm of argon and 60 W cm(-2) A(-1) sr(-1) in 32 atm of helium (slow charged). All values were reproducible to within 10%, the absolute error being estimated to be smaller than +/-20%. Equivalent maximum blackbody temperatures of the channel surface in air were 62,000 K (pulse charged) and 38,000 K in argon and 54,000 K in helium (slowly charged). Maximum spectral radiant intensity in 1 atm of air was 0.18 W A(-1) sr(-1) at 4850 A (pulse charged).
authors.forename: H
authors.initials: H
authors.lastname: Krompholz
authors.forename: H
authors.initials: H
authors.lastname: Fischer