On some methods for the mass production of Po-α-Be neutron sources

Some methods for the preparation of Po-α-Be neutron sources are discussed in this paper. A detailed description is given of one of the “wet” methods of preparing Po-α-Be sources, which consists in the preparation of a uniform mixture of polonium and beryllium by passing a solution of polonium nitrate through beryllium powder, followed by the drying and grinding of the mixture obtained. A method for obtaining polonium nitrate free from copper contamination is described. The method described is not suitable for the mass production of sources because of the high neutron activity accompanying the main technological operation. For the mass production of sources a “dry” method is recommended which is a modification of the method proposed by Brean and Hertz. Copper powder mixed in with a known amount of Po210 is weighed out into containers which are then filled with beryllium powder. When the hermetically shut containers are heated, the polonium volatilizes and is distributed uniformly throughout the mixture. With this method it is possible to prepare sources with a yield of (2.1±0.2) · 106 neutrons/sec per 1 curie of Po210 under conditions which ensure personnel safety.