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 mCi²²Na source are moderated by a thin layer of solid neon. A magnetic guiding system delivered up to 5×10⁶ 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 by⁶⁴Cu, which has a much higher activity. Beam intensities up to 10⁹ e⁺/sec are expected.