AUTOMATION OF A PLANE GRATING SPECTROGRAPH

A Zeiss model PGS-2 plane grating spectrograph was automated by replac ing its photograph film detection system with an EGG-Reticon 1024S pho todiode array (PDA) and by controlling the main instrument functions t hrough the use of a home-made interface connected to a microcomputer. The array was cooled by four Peltier elements to allow integration of the emitted light for up to 40 s. The interface performs data acquisit ion from the sensor array, controls the grating position and the excit ation source. A QuickBasic 4.5 program manages the interface, for data storage and treatment, and allows a graphical display and user-friend ly interaction. Results show an absolute standard deviation for the wa velength localization of +/- 0.036 nm, and a spectral resolution of 0. 05 nm at 443 nm when a 651 grooves/mm grating is employed. In each sca n, the sensor array can collect data in a 18.7 nm wide window. Sensiti vity was inferred from experimental data that showed an accurate local ization of emission lines for Sn and Cu present in metal alloys at 0.0 06 and 0.03%, respectively. Quantitative results obtained for determin ation of Mn in steel samples and Ph in aqueous solution are also prese nted.