Solid neon moderator for positron-trapping experiments

Abstract

A solid neon moderator using a two-stage, closed-cycle refrigerator was installed in an experiment to accumulate positrons in a Penning trap. This moderator replaced a single-crystal tungsten film moderator and yielded an approximate 20-fold improvement in the positron-trapping rate. Experience with the new moderator in a relatively poor vacuum environment of p ~ 1 × 10−7 Torr is discussed.