Journal Article

IMPULSE-2025-00031

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Injection, confinement, and diagnosis of electrons and positrons in a permanent magnet dipole trap

von der Linden, J. ; Nißl, S. ; Deller, A. ; Singer, M. ; Belmore, N. ; Hugenschmidt, C. P.MLZ* ; Pedersen, T. S. ; Saitoh, H. ; Stenson, E. V. (Corresponding author)MLZ*

2024
Springer Heidelberg

Please use a persistent id in citations: doi:10.1140/epjd/s10053-024-00821-x

Abstract: Prerequisites for the goal of studying long-lived, magnetically confined, electron–positron pair plasmas in the laboratory include the injection of both species into the trap, long trapping times, and suitable diagnostic methods. Here we report recent progress on these tasks achieved in a simple dipole trap based on a supported permanent magnet. For the injection of electrons, both an drift technique (of a 2–μA, 6-eV beam) and “edge injection” (from a filament emitting a few mA and biased to some tens of volts) have been demonstrated; the former is suitable for low-density beams with smaller spatial and velocity spreads, while the latter employs fluctuations arising from collective behavior. To diagnose the edge-injected electrons, image potentials and currents induced on a wall probe, the magnet case, and wall electrodes were measured. Confinement of drift-injected positrons, measured experimentally, exhibited at least two well-separated timescales. Simulations reproduced this qualitatively, using a simple model of elastic collisions with residual background gas, and point to small adjustments for increasing trapping times. In a major upgrade to diagnostic capabilities, 25 bismuth germanate detectors, placed in three reentrant ports, are able to localize annihilation gammas, which will be used in future experiments to distinguish between different loss channels.

Keyword(s): Instrument and Method Development (1st) ; Instrument and Method Development (2nd)

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Contributing Institute(s):

1. NEPOMUC (NEPOMUC)

Experiment(s):

1. NEPOMUC: Neutron induced positron source munich (SR11)

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Database coverage:
; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; DEAL Springer ; DEAL Springer ; Ebsco Academic Search ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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