Wenderoth, Lind & Ponack
Method and apparatus for controlling measurement in a spectrophotometer
 In a spectrophotometer of double beam type using automatic gain control, preparatory scanning is first carried out by scanning reference and sample cells with radiation of varying wavelengths both in an empty state, and controlling the gain of a photo detector at each wavelength such that a detector output responding to a sample cell transmitted beam may become constant while storing a detector output responding to a reference cell transmitted beam. Measurement of a sample material is then carried out at each wavelength by scanning the reference cell and the sample material-charged sample cell, reading out the reference output stored in the preparatory scanning stage as a reference voltage, and controlling the gain of the detector such that a detector output responding to a reference cell transmitted beam may be equal to the reference voltage. 
Japan Spectroscopic Co., Ltd.
G G G
G01J G01J G01N
inventional additional additional
Shinichiro
Watanabe