A magnetic-lens electron spectrometer; radiations from 5.3 year cobalt60.

An impro ved magnetic-lens spectrometer , similar in principle to tha t described by D eutsch, Elliott, and Evans 1 has been cOllsi,ru cted. The struc t ure, operation, and method of calibrat ion, using a ThB + C deposit, is d escrib ed. R es ults of m easurem ents of t he primary beta-ray specti'um of COHO a nd of t he gamma-ray spect; um converted in a uran ium radiator a rc gi ven. These g ive an end point of 0.3 10 fo r the val ue repo rted by Deutsch, E lliott, a nd R oberts 2 of 0. 308 ± 0.008 million elect ron volt (l\Iev). Two gamm a rays were m eas ured at 1.16 and 1.32 M ev, likewi se in agreeme nt with the values of 1.10 ± 0.03 and 1, 30 ± 0,03 ;\Ie v , g iven by the same a ut hors.