The Thick Target (a, n) Production Yield of Sulphur

The thick target (a, n) production yield curve for sulphur is not available. It is natural therefore to ask how yields for sulphur are to be estimated in the nuclear fuel cycle when a - emitting actinides and sulphur may be intimately mixed. In this work we analyse two literature experiments conducted on dry mixed compounds which support the conclusion that sulphur is not a prolific (a, n) emitter for plutonium alpha particles. An upper bound is set in terms of the (a, n) yield of pure UO2. This is a convenient reference material for use in the nuclear fuel cycle. Using passive neutron counting techniques the (a, n) to spontaneous fission yield from three samples of Pu (SO4)2 : 4H2O of different isotopic composition have been determined. These measurements support the conjecture that the thick target S(a, n) yield is not in the same class as the light elements Li, B, Be and F. Rather its yield to Pu a - particles is comparable to that from pure PuO2. As an interim measure, pending availability of high quality experimental S(a, n) yield curve data, it is convenient to use the yield curve for UO2(a, n) in its place.