Use of a tungsten filament lamp as a calibration standard in the vacuum ultraviolet.
A tungsten ribbon filament lamp fitted with a sapphire window and operated at a temperature of 2800 K is shown to be a stable reproducible calibration source over the wavelength range 1500-2700 A. Spectra of the lamp obtained using a 50-cm Ebert spectrometer and an extreme-solar-blind photomultiplier with pulse-counting electronics are reproducible to better than +/-10% over this spectral range. Careful calibration of the spectrometer and photomultiplier has allowed a direct measurement of the absolute spectral radiance of the lamp, hence the apparent emissivity of the hot tungsten filament, from 1500 A to 2700 A.
Buckley
J L
JL