GB661497A - Spectrographic apparatus - Google Patents

Abstract

661,497. Photo-electric spectroscopes. COMPAGNIE DE PRODUITS CHIMIQUES ET ELECTROMETALLURGIQUES, ALAIS, FROGES, ET CAMARGUE. May 24, 1949 [May 24, 1948], No. 13833/49. Class 40 (iii). [Also in Group XX] A spectrum produced by a prism can be photographically recorded or examined by photo-electric cells. As shown in Fig. 2, the spectrum is projected on to an area Sp and a photographic slide Cp can be swung away and replaced by a box Cc containing two cells C2, C1, one of which is adjusted to view a standard line and the other of which can be traversed to receive any desired line ; the outputs of the two cells are compared to .determine the ratio of the intensity of the two lines. As shown in Fig. 3, a mirror M in its lower position allows the spectrum to fall on the photographic slide Cp, and when rotated into its upper position deflects the spectrum via mirror 10 to the photo-electric apparatus Cc; spring-controlled shutters 8, 7 cut off light from the mirror 10 and open aperture 11 when the mirror M is in its lower position, and when the mirror M is in its upper position, aperture 11 is closed and aperture 16 is open. The cells C1, C2, Fig. 4, may have their sensitivity adjusted by choice of resistances R1, R2; the cells feed amplifiers Al, A2 whose outputs are rectified at D1, D2 to charge condensers F1, F2, whose potentials are compared by a potentiometer circuit.