Abstract

A method is described for the measurement of the rise and decay of luminescence in phosphors excited by cathode-ray beams. It is particularly suited to the investigation of phosphors classed as fast, i.e., those in which major changes in intensity occur in a few microseconds. The method is based on the use of a supersonic cell arranged to produce the Debye-Sears diffraction effect. High speed shutter action is obtained by modulating the supersonic wave train to produce short steep-sided pulses. Light intensities sufficient for direct measurement in terms of photoelectric cell response are obtained by synchronizing the periodic excitation of the phosphor with the diffracting wave pulses in the liquid. Time intervals in the decay process are measured in terms of distances traversed by the sound waves in water. Several methods of using the device are described, and some results obtained by these methods are shown.

© 1941 Optical Society of America

Final Measurements of the Velocity of Light

Wilmer C. Anderson
J. Opt. Soc. Am. 31(3) 187-197 (1941)

Radiant Energy Measurements with Thermopiles

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An Automatic Recorder of Spectral Sensitivity of Photoelectric Surfaces

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