A Wide Range, Rapid Scanning Spectrometer for Emission and Absorption Measurements

A new, very wide spectral range, fast scanning spectrometer that combines high speed with good resolving power has been developed. The instrument operates with an f number in the vertical and horizontal plane of f/3 and f/17, respectively, and with a useful slit height of 3 cm. The theoretical resolving power in first order is 14,000 using an 1180-lines/mm grating. The optical layout is basically an asymmetrical Czerny-Turner arrangement with the grating at the center of curvature. The scanning element is a six sided, air turbine driven mirror that allows the whole spectrum from zero to 1.2 micro in first order to be scanned in about 70 microsec at mirror speeds of 1500 rps. The wide variation in the spectral response of the instrument presents recording problems, but ways of circumventing or diminishing those problems are suggested. A high intensity, end-on, pulsed flash tube has been used as a source for absorption spectroscopy. Some experiments are described, where the system has been appli d to emission or absorption measurements.