DESIGN AND DEVELOPMENT OF 0.5 M SCANNING MONOCHROMATOR AND ITS APPLICATION TO 15 N ANALYSIS R. P. Shukla, D. V. Udupa, Manika Mallick, Sanjay Somkuwar, B. J. Shetty, A. K. Sinha 1 and V. C. Sahni Spectroscopy Division 1 A. K. Sinha is with Centre for Design and Manufacture, BARC. Introduction We have been working on the development of monochromators in Spectroscopy Division since 1980. Based on the optical design of Czerny- Turner [1,2] type of optical configuration, we had first developed a 1.0 m monochromator-cum spectrograph[3] with a resolution of 0.2 Å using a plane diffraction grating of 1200 grooves/mm. The instrument could be used in photographic mode and the monochromator mode. This instrument was used for beam-foil spectroscopic research for several years. The second monochromator, we developed, was a 1.0 m scanning monochromator[4] with a spectral resolution of 0.2 Å by using a plane diffraction grating of frequency 3600 grooves/mm. This instrument was found satisfactory for the spectrochemical analysis of rare earth impurities in solution form. The third instrument [5.6], we could develop, was 0.5m Raman spectrograph having a spectral resolution of 1.2 Å by using a grating of frequency 1200 grooves/mm. In this instrument, we used a CCD as a detector for recording the Raman spectra. The instrument gave satisfactory results for Raman spectroscopic applications. In all the