Two different magnetic lenses, suitable for use as objective lenses in positron beams, which can be positioned outside the vacuum system, behind the target are presented. The first is a single-pole lens, optimised as a parallising objective for the reemission of slow positrons from a remoderator. The second is a side-gap lens designed as a probe-forming lens for variable incident energy up to 30 keV with no change in its optical properties. Additionally the effect of an additional solenoid field on the properties of the probe-forming lens has been investigated. © 1995.    «

Two different magnetic lenses, suitable for use as objective lenses in positron beams, which can be positioned outside the vacuum system, behind the target are presented. The first is a single-pole lens, optimised as a parallising objective for the reemission of slow positrons from a remoderator. The second is a side-gap lens designed as a probe-forming lens for variable incident energy up to 30 keV with no change in its optical properties. Additionally the effect of an additional solenoid field...    »