Intensities in Raman spectra III. A photoelectric recording Raman spectrometer for intensity measurements

A description is given of a Raman apparatus designed primarily for intensity measurements by direct photo-electric recording. A special feature is a high- intensity light source with four Toronto-type mercury arcs. It is possible to use a variety of sample volumes and to make measurements on samples over a wide range of temperatures both above and below room temperature. Semi-quantitative polarization measurements can also be made. The recording system uses an E. M. I. eleven-stage photomultiplier cell with a. c. amplification at 285 c/s, followed by rectification in a phase-sensitive homodyne circuit. The output is fed to a Cambridge recording potentiometer. Details of calibration for intensity measurements are given and sample records are shown illustrating the various applications of the apparatus.