Solid neon moderated electrostatic or magnetic positron beam

A high intensity variable energy positron beam has been constructed at Brookhaven National Laboratory (BNL). Positrons from a 97 mCi 22Na source are moderated by a thin layer of solid neon. A magnetic guiding system delivered up to 5 x 106 e+/sec to an experiment. Currently, tests are under way to facilitate the operation with the magnetic guiding system or - for other experimental sites - with an electrostatic beam transport. The electrostatic lenses are fabricated from μ-metal. No compensation of the earth's magnetic field is required. Several experiments can utilize the beam on a time-sharing basis. In the near future, the source will be replaced by 64Cu, which has a much higher activity. Beam intensities up to 109 e+/sec are expected. (orig.)