A4 Article in conference proceedings
Time-resolved measurement of optical emission line profiles from electron cyclotron resonance ion source plasma (2024)

Timonen, O., Koivisto, H., Kronholm, R., & Toivanen, V. (2024). Time-resolved measurement of optical emission line profiles from electron cyclotron resonance ion source plasma. In 20th International Conference on Ion Sources (Article 012008). IOP Publishing. Journal of Physics : Conference Series, 2743. https://doi.org/10.1088/1742-6596/2743/1/012008

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Publication details

All authors or editors: Timonen, Oskari; Koivisto, Hannu; Kronholm, Risto; Toivanen, Ville

Parent publication: 20th International Conference on Ion Sources

Conference:

Place and date of conference: Victoria, BC, Canada, 17.-22.9.2023

Journal or series: Journal of Physics : Conference Series

ISSN: 1742-6588

eISSN: 1742-6596

Publication year: 2024

Publication date: 01/05/2024

Number in series: 2743

Article number: 012008

Publisher: IOP Publishing

Publication country: United Kingdom

Publication language: English

DOI: https://doi.org/10.1088/1742-6596/2743/1/012008

Publication open access: Openly available

Publication channel open access: Open Access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/95129

Abstract

Optical emission spectroscopy provides a non-invasive method to probe the properties of hot and highly charged magnetically confined plasmas. The optical emission line profiles enable, for example, to identify the different species and characterize the relative population densities and temperatures of the ions and neutrals forming the plasma. The feasibility of this approach has been demonstrated at the University of Jyväskylä accelerator laboratory by measuring the light emitted by Electron Cyclotron Resonance Ion Source (ECRIS) plasma with a high-resolution spectrometer setup POSSU (Plasma Optical SpectroScopy Unit). In these previous studies, the emission line profiles were measured by scanning the desired wavelength range by rotating the diffraction grating of the spectrometer. This process is slow compared to many interesting plasma phenomena, thus limiting the applicability of the setup. Recently, POSSU has been upgraded by changing the light sensor from a photomultiplier tube to a position-sensitive imaging sensor. As a result, it is possible to measure simultaneously a 1 - 2 nm wavelength range, with a spectral resolution in the order of picometers, without moving the grating. This enables a time-resolved study of the optical emission line profiles. By turning the grating, the measured wavelength region can be chosen between 370 nm and 870 nm, which covers the visible light spectrum. The time-evolution of optical emission line profiles emitted from the JYFL 14 GHz ECRIS plasma, during shifting plasma conditions induced by changing the gas balance, has been measured to demonstrate this new capability. The time-evolution of temperatures and emission intensities of selected ion species, correlated with extracted ion beam currents, are presented.

Keywords: plasma physics; cyclotrons

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