An optical system is described in which ultraviolet light from a suitable source is dispersed by a grating monochromator and focused on a specimen. Fluorescent light from the specimen passes through a second grating monochromator and is detected by a photomulitplier tube. The specimen is placed in a stand which rests on a kinematic trolley, by means of which the specimen is brought into focus and which allows stands with reference markings, an MgO surface, or a cold cell to be used.
The optical system is calibrated photometrically by means of a standarized tungsten-quartz lamp. The spectral sensitivity characteristics of the detecting photomultiplier, together with its associated monochromator and mirrors, are corrected by means of a cam driven in synchronism with the wavelenght drive drive of the detecting monochromator.
In order to cancel fluctuations in the exciting light source a fraction of the light emerging from the source monochromator is focused on to a second photomultiplier, whose output is used to operate a servo system. The recorded spectrum is thus a measure of the ratio of fluorescent to exciting light. The currents from the photomultipliers are amplified by dc amplifiers with silicon diode modulators, which are described.
F. R. LIPSETT, "Versatile Apparatus for Automatic Recording of Absolute Fluorescent Spectra," J. Opt. Soc. Am. 49, 673-679 (1959)