| abstract |
In a spectrophotometer having photodetectors positioned at fixed wavelengths, the photodetector is divided into three subdetectors (41,42,43), a main subdetector (42) on the wavelength of interest and two background subdetectors (41,43) located on each side of the main subdetector (42), the background subdetectors (41,43) together having area equal to that of the main subdetector (42), the background subdetectors (41,43) being connected in polarity reverse that of the main subdetector (42) to correct for changes in background radiation. |