Large scale positron production for physics needs via fission reactors Available to Purchase

Condensed matter physics, antimatter factories, and large lepton colliders constitute three generic physics areas which seek more intense positron beams. Radioactive nuclei have long served as positron sources. BNL has developed a technique which combines their neutron activation in a high‐flux research reactor with subsequent reconstitution as a self‐moderating and ‐collimating, positron‐emitting crystal. Examination of the reactor physics indicates that little more can be achieved through higher neutron fluxes or different nuclide targets; however, a real prospect exists for multi‐magnitude increase through large‐scale volume irradiation in ‘‘test reactors’’. There remains to develop a large‐scale technique to process large‐volume positron sources into a compact beam.