A1 Journal article (refereed)
Slit extraction and emittance results of a permanent magnet minimum-B quadrupole electron cyclotron resonance ion source (2024)

Kosonen, S., Kalvas, T., Koivisto, H., Tarvainen, O., & Toivanen, V. (2024). Slit extraction and emittance results of a permanent magnet minimum-B quadrupole electron cyclotron resonance ion source. Nuclear Instruments and Methods in Physics Research. Section B : Beam Interactions with Materials and Atoms, 546, Article 165147. https://doi.org/10.1016/j.nimb.2023.165147

JYU authors or editors

Publication details

All authors or editors: Kosonen, Sami; Kalvas, Taneli; Koivisto, Hannu; Tarvainen, Olli; Toivanen, Ville

Journal or series: Nuclear Instruments and Methods in Physics Research. Section B : Beam Interactions with Materials and Atoms

ISSN: 0168-583X

eISSN: 1872-9584

Publication year: 2024

Publication date: 04/11/2023

Volume: 546

Article number: 165147

Publisher: Elsevier

Publication country: Netherlands

Publication language: English

DOI: https://doi.org/10.1016/j.nimb.2023.165147

Publication open access: Openly available

Publication channel open access: Partially open access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/91827

Abstract

We present an experimental and simulation study of high charge state ion beams produced with a permanent magnet electron cyclotron resonance ion source (ECRIS) with minimum-B quadrupole magnetic field topology and slit extraction system. The unconventional topology generates fan-shaped plasma flux, favouring a rectangular aperture for beam extraction. We demonstrate successful low-energy transport of the slit beam, achieving up to 25 times higher beam currents compared to a round extraction aperture. Maximum beam intensities are 1.5 and 15 μA for argon 11＋ and 9＋, respectively. The results indicate microwave power-limited beam production. Emittance values are comparable to traditional ECRIS. Unlike in conventional ECRIS, the emittance increases monotonically with increasing charge state due to slit extraction, magnetic topology, and beam transport characteristics. The experimental transport efficiency for helium ranges from 32% to 50%, depending on the total beam current. The losses primarily occur due to the dipole magnet’s insufficient vertical aperture.

Keywords: particle accelerators; cyclotrons; plasma physics

Free keywords: ion source; electron cyclotron resonance; ion beam; plasma confinement; emittance; beam extraction

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Ministry reporting: Yes

Reporting Year: 2024

Preliminary JUFO rating: 2