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A Small Air Turbine Driven Step Sector

Volume 7, Number 3 (Aug. 1953) Page 129-131

Bennett, H. Stanley; Quinton, Wayne E.; Othberg, Richard; Reis, George W.


The small air turbine driven step sector which is to be described in this paper was developed in order to meet a need arising in a research problem involving microspectoscopy. A general discussion of microspectroscopy has been published by Loofbourow (1). In the course of our study it was desired to obtain absorption spectrograms of small elements (1 - 10μ diam.) of biological tissues. The procedure followed was to place the object on a microscope slide on the stage of a microscope and, by means of the microscope optical system, to project an enlarged image of the object in the image plane of a photomicrographic camera. A series of photographs of the object was then made. Each photograph was taken with the object illuminated with a different wavelength, a wavelength being selected for each of the points which was to be experimentally determined for the absorption spectrogram. The developed photographic image of the object in question was then photometered and compared to a set of known reference densities on the same plate. A value for d, (log10 Io/I) could thus be obtained. The small step sector discs described here were used to obtain the reference densities which served as calibrations.