DEVELOPMENT OF A NEAR INFRARED-VISIBLE SPECTROPHOTOMETER AT UTMSL

Author Institution: Molecular Spectroscopy Laboratory, Department of Physics and Astronomy University of Tennessee, KnoxvilleA high resolution spectrometer has been designed to operate in the wavelength region spanning the near infrared through the visible. The monochromator configuration is a 1 1/4 meter Ebert-Fastie. The grating is a Bausch and Lomb $5 \times 10$ inch, 316 groove per millimeter echelle driven by a programmable stepping drive. A Perkin Elmer Model 112 spectrometer equipped with a $CaF_{2}$ prism has been modified to act as a predisperser. The sample section follows the monochromator so that only the highly dispersed light excites the sample gas. An interesting feature of the sampling section is the method of double beaming. A beam flipping mirror shifts the sample beam through two paths to a single detector. The signal from the detector [lead sulphide or photomultiplier] is amplified and digitized by an $A/D$ converter and then routed by a PDP-11 computer system to a storage buffer. Design features and performance will be discussed