PRECISION GAMMA RAY ENERGY MEASUREMENTS

Abstract

A double focusing beta ray spectrometer has been constructed and tested in this laboratory. Previous work Included investigation of the field shape and tests of focusing, using the Th F line to determine the optimum baffle and counter dimensions. In this work, a low background coincidence geiger detector has been developed, and a flip coil- galvanometer arrangement has been installed which is capable of giving 0.1% accuracy on magnetic field measurements. Using these improvements, we have investigated the gamma ray spectrum of In, bringing to light two previously unreported gamma rays, and thus defining a new excited level in Cd . With a beta source of high specific activity, a search was made for the internal conversion lines due to these gamma rays. An accurate measurement of the beta end point has been obtained.