Abstract

The possibility of using photo-multipliers for the detection of the change in light intensity due to the absorption of free radicals in chemical reactions has been investigated. A discussion of the sensitivity of photo-tubes considers the effects of the random fluctuations of the photoelectric current, and the limitations due to the dark current and the fatigue of the tube. A balanced direct current circuit using two photo-multipliers is described. With this circuit, it is possible to detect a change of light intensity of 1 part in 10,000.

© 1950 Optical Society of America

Multiplier Photo-Tube Characteristics: Application to Low Light Levels*

Ralph W. Engstrom
J. Opt. Soc. Am. 37(6) 420-431 (1947)

The Measurement of the Intensity Ratios of Spectral Lines with Electron Multiplier Photo-Tubes

K. G. Kessler and R. A. Wolfe
J. Opt. Soc. Am. 37(3) 133-144 (1947)

Photoelectric Light-Scattering Photometer for Determining High Molecular Weights*

B. A. Brice, M. Halwer, and R. Speiser
J. Opt. Soc. Am. 40(11) 768-778 (1950)

The Compensation for Seeing in Stellar Photoelectric Spectrophotometry*

W. A. Hiltner and A. D. Code
J. Opt. Soc. Am. 40(3) 149-152 (1950)

The Electro-Optic Effect in Uniaxial Crystals of the Dihydrogen Phosphate Type.*,† III. Measurement of Coefficients

Robert O’B. Carpenter
J. Opt. Soc. Am. 40(4) 225-229 (1950)