Steiger, T., J. Stehr, H. C. Griffin, M. Skalsey, J. Van House, Development of Intense, Long-lived Positron Sources Nuclear Instruments and Methods in Physics Research A299 pp. 255-260, 1990
There are many important applications for very intense positron beams (over 1 Ci of positrons); however, the radioactive sources needed to produce these beams are not readily available. Two separate processes for fabricating inexpensive, intense positron sources from Na-22 and Co-58 have been investigated. Both procedures have been successfully tested with low levels (mCi) of activity.