Isotopes of Berkelium and Californium Produced by Neutron Irradiation of Plutonium

Samples of berkelium and californium have been separated from neutron-irradiated plutonium and carefully purified. Pure Cf²⁴⁹ daughter has been separated from the Bk²⁴⁹. The californium sample and its curium decay products have been mass analyzed. The berkelium fraction contained 314±{}8 day Bk²⁴⁹ emitting 0.114±{}0.015 Mev beta particles and 5.417±{}0.015 Mev and 5.03±{}0.03 Mev alpha particles. The α-β ratio was found to be (2.2±{}0.3)×{}10^-5. The californium sample contained: 360±{}40 year Cf²⁴⁹ emitting 5.808±{}0.010, 5.93±{}0.02, and 6.20±{}0.02 Mev alpha particles; 10.9±{}0.8 year Cf²⁵⁰ emitting 6.020±{}0.010 Mev alpha particles; 800-year Cf²⁵¹; 2.55±{}0.15 year Cf²⁵² emitting 6.112±{}0.015 Mev alpha particles; and 17±{}1 day Cf²⁵³.