The light leaves the dispersion section of the monochromator and passes into the section of the spectrophotometer which determines whether the detector is monitoring radiation from the reference or sample cell. To create this Dual-Beam mode, two choppers are used. These choppers rotate synchronously with the light passing through the sample 1/3 of the time, the reference 1/3 of the time, and a dark current measurement made 1/3 of the time by the detector.
Michael R. Ross
Chemistry Department, College of St. Benedict/St. John's University
St. Joseph, MN 56374
320-363-5482
Comments to author: mross@csbsju.edu
Revised: 1/1/98
URL: http://www.users.csbsju.edu/~mross/ch336/dms90DualBeam.html
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