Work function behavior of a biased C12A7 electride in low temperature hydrogen plasmas

  • The development of ion sources for NNBI systems at future fusion devices like ITER or DEMO is based on the surface production of negative hydrogen ions. Thus, low work function converter surfaces are mandatory. Besides the state-of-the-art technique of continuous Cs injection during ion source operation, alternative materials are desirable to overcome the drawbacks of volatile Cs coatings. In this work, a C12A7 electride material is studied regarding the work function behavior in a hydrogen and deuterium plasma environment at ion source relevant conditions. The minimum measured work function obtained during the campaign is 2.9 ± 0.1 eV, with an optimization potential to lower values at better vacuum conditions and higher annealing temperatures. Biasing the sample during plasma operation exhibits a strong impact on the work function performance, which is dependent on the polarity and the applied bias potential. The minimum work function obtained for the C12A7 electride used in thisThe development of ion sources for NNBI systems at future fusion devices like ITER or DEMO is based on the surface production of negative hydrogen ions. Thus, low work function converter surfaces are mandatory. Besides the state-of-the-art technique of continuous Cs injection during ion source operation, alternative materials are desirable to overcome the drawbacks of volatile Cs coatings. In this work, a C12A7 electride material is studied regarding the work function behavior in a hydrogen and deuterium plasma environment at ion source relevant conditions. The minimum measured work function obtained during the campaign is 2.9 ± 0.1 eV, with an optimization potential to lower values at better vacuum conditions and higher annealing temperatures. Biasing the sample during plasma operation exhibits a strong impact on the work function performance, which is dependent on the polarity and the applied bias potential. The minimum work function obtained for the C12A7 electride used in this experiment is substantially higher than what is achieved with in situ caesiation (~ 2 eV), but the sample has demonstrated promising properties in terms of plasma resilience.show moreshow less

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Metadaten
Author:Adrian HeilerORCiD, Roland FriedlORCiDGND, Ursel FantzORCiDGND, Riccardo Nocentini, M. Sasao
URN:urn:nbn:de:bvb:384-opus4-1173213
Frontdoor URLhttps://opus.bibliothek.uni-augsburg.de/opus4/117321
ISSN:0094-243XOPAC
Parent Title (English):AIP Conference Proceedings
Publisher:AIP Publishing
Type:Article
Language:English
Year of first Publication:2021
Publishing Institution:Universität Augsburg
Release Date:2024/12/05
Volume:2373
Issue:1
First Page:020004
Note:
Seventh International Symposium on Negative Ions, Beams and Sources (NIBS 2020), 1–10 September 2020, Oxford, United Kingdom
DOI:https://doi.org/10.1063/5.0057482
Institutes:Mathematisch-Naturwissenschaftlich-Technische Fakultät
Mathematisch-Naturwissenschaftlich-Technische Fakultät / Institut für Physik
Mathematisch-Naturwissenschaftlich-Technische Fakultät / Institut für Physik / AG Experimentelle Plasmaphysik (EPP)
Nachhaltigkeitsziele
Nachhaltigkeitsziele / Ziel 7 - Bezahlbare und saubere Energie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik
Licence (German):CC-BY 4.0: Creative Commons: Namensnennung (mit Print on Demand)