The Preparation of Pressed Ra+Be Neutron Sources

A method for preparing pressed Ra+Be fast neutron sources is described in detail. Such sources can be made to contain as much as 5 g of Ra. They have the advantage of small volume and constancy of neutron output. The yield of fast neutrons per sec. per g of Ra can be obtained from the relationship $$\mathrm{yield}{\text{=1.7×10}}^7\frac{M_{\mathrm{Be}}}{M_{\mathrm{Be}}{\mathrm{+M}}_{{\mathrm{RaBr}}_2}}.$$