Abstract

The relative intensities of a group of ten lines of the spectrum of a hydrogen discharge tube have been measured both by conventional photoelectric densitometry and with a logarithmic sector. A statistical analysis of the results showed that, for our instruments, photoelectric densitometry is slightly more accurate than logarithmic sector intensitometry; the former method gave an average coefficient of variation, in the measurement of an intensity ratio, of 2% whereas the latter method gave an average coefficient of variation of approximately 4%. However, for a great many applications in spectrochemical analysis the latter method appears to be sufficiently accurate, at the same time having many advantages. It is faster, simpler; intensity ratios are obtained directly without the need of a calibration curve; the method is self calibrating; it does not involve a considerable amount of complicated equipment that requires frequent attention; intensity ratios can be made over a much greater range for a single exposure of the spectrum.

A Photoelectric Colorimeter with Logarithmic Response*

Ralph H. Müller and Gilbert F. Kinney
J. Opt. Soc. Am. 25(10) 342-346 (1935)

Photoelectric Detection and Intensity Measurement in Raman Spectra

D. H. Rank, R. J. Pfister, and P. D. Coleman
J. Opt. Soc. Am. 32(7) 390-396 (1942)

A Photoelectric Reflection-Transmission Densitometer

R. L. Huber and A. B. Rakus
J. Opt. Soc. Am. 39(10) 873-876 (1949)

The Step-Sector in Spectrochemical Analysis

Ralph E. Thiers
J. Opt. Soc. Am. 41(4) 273-276 (1951)

Photoelectric Comparator for Wavelength and Intensity Measurements of Spectra*

David W. Steinhaus
J. Opt. Soc. Am. 49(5) 468-470 (1959)