The Spectrographic Determination of Uranium 235. Part IV. Using a Direct Reading, Littrow, Grating Spectrograph and a Hollow Cathode

Abstract

This report, the fourth of a related series dealing with the isotopic analysis of uranium, describes the use of a hollow cathode source and a 4-m, direct-reading, Bausch and Lomb high-resolution spectrograph. A relative precision of ±3.0%, expressed at the 95% confidence level, was obtained with naturally occurring uranium for a single cathode determination of U235 measured in twenty min. Evidence for a weak uranium line structure interfering with the U235 measurement is presented Minor isotopes, U231 and U236, present up to a few percent at the higher U235 concentrations, did not interfere with U235 measurements. Measurements of U234, however, could not be made in the presence of high U235 concentrations, thereby limiting the determination of total uranium necessary for calculating the percent U235. At the lower U235 concentrations, the concentrations of minor isotopes are generally too small to significantly affect the total uranium content of the sample.