Paul trap for pure positron plasma – A prelude to electron–positron plasma in a laboratory

Abstract

AbstractA scheme to construct a Paul Trap to trap positrons and create ‘Pure Positron Plasma’ has been presented. Positrons from a sealed source (22Na) are moderated down to ∼ 2.5 eV with an energy spread of ≤1 eV with a pre‐treated 1 μm Tungsten moderator held at room temperature with a moderation efficiency ∼ 6 × 10–4 – 2 × 10–3. The energy of moderated positrons is further adjusted to about 42 eV by biasing the moderator before their entry in to the trap. Positrons entering the trap are cooled by a buffer gas (inelastic collisions with N2 or CO2) at low pressure, hence fall in the pseudo‐potential well. This trap will additionally be used as a test bed for future systems with the ability of confining both positrons and electrons simultaneously and to create electron‐positron plasma. In this paper, the physics design and estimations such as, the order of vacuum, geometry, stability parameters a, q (and hence RF voltage and frequency), pseudo‐potential well depths (Dρ, Dz) and space charge limited density of trapped positrons have been discussed. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)