Wave- length standards in the first spectrum of krypton

Abstract

A preliminary investigation of the first spectrum of Krypton was made by the author in 1931 and 1932,* to investigate the suitability of its lines for providing wave-length standards of the highest accuracy. The ten strongest lines in the violet were measured interferometrically, and these preliminary results indicated that the spectrum of krypton was eminently suited to give a system of standard wavelengths. The lines are extremely sharp, easily reproducible, and their distribution is such that it is possible to evaluate the thickness of an etalon without ambiguity, even when the roughly estimated thickness may be in error by several hundred waves. The spectrum has the advantage that the brightest lines are in the violet part of the spectrum, which eliminates the necessity of using panchromatic plates for photographing them, and they are of such great intensity that their photography takes only about one-tenth of the time required for the primary standard.