Abstract
A computer-controlled densitometer for data acquisition and high speed analysis of photographically recorded optical emission spectra has been developed. The instrument scans and digitizes spectra and stores the data sequentially in computer memory. A high-resolution linear measurement transducer mounted on a Jarrell-Ash densitometer monitors the plate position as the spectrum is scanned. The transducer measurement is accurate to within 0.001% over a range of about 340 mm on a glass photoplate. Computer algorithms for locating and identifying peaks and for calculating the wavelengths of spectral lines from their positions in the spectrum are described. With the use of a calibration curve based on the measured positions of three known spectral lines, the wavelength of any spectral line can be determined to within 0.005 nm, and the transmittance of a peak in the recorded spectrum can be measured to within 1%. The wavelengths and transmittances of all detectable spectral lines in the digitized emission spectrum are determined in less than two minutes.
Get full access to this article
View all access options for this article.