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.