PHOTOPRODUCTION OF RADIOISOTOPE WITH 20-Mev LINEAR ELECTRON ACCELERATOR. II. PRODUCTION RESULT

Eighteen radioisotopes were produced by photonuclear reactions with bremsstrahlung. Photoreaction yield and radiochemical purity were quantitatively estimated. The estimation was carried out by the measurements of gamma spectrum and decay rate. In some cases, chemical separation was used to separate ( gamma ,n) and ( gamma ,p) products or to determine the radiochemical impurities in the products. Calcium carbonate was irradiated and production yields of Ca/sup 47/, K/sup 42/, and K/sup 43/ were estimated by separating Ca and K by precipitation. By irradiating a Ni target, high purity Co/sup 57/ with a high specific activity was obtained as a composite of the ( gamma ,p) product and the daughter of ( gamma ,n) product. In the photoproduction of Cs/sup 132/, cesium chloride or cesium nitrate was irradiated. In this case, the other contaminant was successfully lowered by the use of high purity target so that 1.5 x 10/sup 5/ of Cs/sup 134//Cs/sup 132/ was obtained and Cs/ /sup 134/, was the main gamma emitter in the product. Mn/sup 54/ and As/sup 74/ were produced by the irradiation of KMnO/sub 4/ and As/sub 2/O/sub 3/. F/sup 18/ and Ti/sup 45/ were prepared by irradiation of LiF and TiO/sub 2/. Mn/sup 54/,more » Y/sup 88/, Nb/sup 92/ , and In/sup 114m/ were produced by ( gamma ,n) reaction. Other 168/, Lu/sup 174/ , Re/sub 184/, and Au/sup 196/, were also produced by bremsstrahlung irradiation. The isotopes produced were always of high purity; in some cases, there was no need for purification. Specific activity was easily achieved up to 1 mC/g in heavy elements by the ( gamma ,n) reaction. (P.C.H.)« less