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AUTOMATIC SCANNING SPECTROPHOTOMETER WITH PUNCH TAPE OUTPUT FOR BIO‐APPLICATIONS
Author(s) -
SEIM T.,
PRYDZ S.,
HOLTSMARK T.
Publication year - 1972
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1972.tb06287.x
Subject(s) - monochromator , optics , chromaticity , grating , spectral resolution , stray light , noise (video) , materials science , physics , wavelength , optoelectronics , computer science , spectral line , artificial intelligence , astronomy , image (mathematics)
— An automated scanning spectrophotometer has been constructed for the measurement of color‐vision test stimuli and various types of luminescence. Recorder and paper tape output data have been provided. Processing of the spectral information is performed on a CDC 3300 computer. Photoelectric detection is employed. An inexpensive Jarrel‐Ash 0.25 m, f /3.6 Ebert type monochromator is employed with two gratings, blazed for 300 and 600 nm, respectively. The spectral sweep range can be easily set by electromechanical registers, as can the number of sweeps required. Photon numbers are integrated by a counter over 5 nm blocks, and this procedure sets the limit of resolution. At present the spectral range is from 400 to 800 nm. By calibration against an ultraviolet‐emitting standard lamp the useful range can easily be extended downwards to 250 nm. Computer programs have been written which add several spectra when these are faint and produce a mean spectrum in the form of listed and plotted output. The mean noise level is subtracted. Subprograms have been made for the smoothing of poor spectral data where noise predominates and for the correction for stray light and grating ‘ghosts’ in the monochromator. A program has been made which performs colorimetric analyses of light sources, spectral filters, and pigmented surfaces. The dominant wavelength and the excitation purity are computed and given in CIE chromaticity coordinates and three‐stimulus values.