Bunched beam generation of polarized positrons in TOPPS-II

We have constructed a bunched beam generator of polarized slow positrons, n amely TOPPS-II (Tokyo Metropolitan University Polarized Positron Beam Syste m) using the magnetic transportation. The positrons emitted from 100 mCi Na -22 are implanted on the tungsten moderator of 6 mu m thickness. Reemitted positrons, accelerated to 200 eV and guided with 100 G magnetic field of so lenoid coils, are chopped to be 40 ns every 200 ns and bunched into 2 ns ti me width. In this paper, we present the results of the overall performance of TOPPS-II. (C) 1999 Published by Elsevier Science B.V. All rights reserve d.