A Fourier transform spectrometer for the vacuum ultraviolet: design and performance

Abstract
A Fourier transform spectrometer designed to operate at high resolution at wavelengths down to 170 nm is described. The principal instrumental parameters are: mirror travel, 200 mm; resolving limit, 0.025 cm-1; collimator aperture ratio, f/25; overall dimensions of vacuum tank, 1.5 m*0.25 m*0.25 m. Test results show (i) a signal-to-noise ratio in the transformed spectrum at 200 nm better than 1000:1 for an iron-neon hollow cathode lamp at a resolving power of quarter of a million, (ii) fully resolved line profiles in the same source at a resolving limit of 0.03 cm-1 (resolving power 1.5*106), (iii) relative wavenumbers of Fe II emission lines reproducible to +or-0.0006 cm-1 (3.4 fm), and (iv) a significant luminosity gain over grating spectrometers operating in the same region.