From introductory paragraph: "The study of the counting techniques of gamma-emitting radioisotopes is of a great deal of interest to workers in the field of radiochemistry. Of particular interest to the long-lived gamma emitting isotope of yttrium which is commonly prepared by a deuteron bombardment of strontium and is reported to decay by K-capture. This isotope, which is of interest in the fields of biochemistry and metallurgy was tentatively assigned to mass 86. Since a 2.0 hour activity was observed from a neutron irradiation of yttrium, the assignment was considered fixed. Subsequent work indicated a possibility of a long-lived gamma emitting activity arising in the fast neutron irradiation of yttrium. The published data did not agree with theoretical calculations as to the possibility of these two activities being isomers. This work was undertaken to study the characteristics of the radiations from the isotopes; to have data available on the long-lived activity; and, to attempt to fix the mass assignment."