Separation of plasma species for investigating the impact of hydrogen plasmas on the work function of caesiated surfaces

Separation of plasma species for investigating the impact of hydrogen plasmas on the work function of caesiated surfaces | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Separation of plasma species for investigating the impact of hydrogen plasmas on the work function of caesiated surfaces Adrian Heiler, Roland Friedl, Ursel Fantz This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5003629/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 11 You are reading this latest preprint version Abstract In negative hydrogen ion sources in situ adsorption of Cs is typically used to generate low work function converter surfaces. The achievement of a temporally stable low work function coating is, however, challenging due to the hydrogen plasma interaction with the surface. Particularly in ion sources for neutral beam injection systems for fusion with pulse lengths of minutes to hours temporal instabilities are a major issue and limit the source performance. To clarify the influence of the hydrogen plasma on the converter surface, investigations are performed at an experiment equipped with an absolute work function diagnostic based on the photoelectric effect. Caesiated surfaces are exposed to the full plasma impact by the generation of plasmas in front of the surface as well as to selected plasma species (H atoms, positive ions and VUV/UV photons) from an external plasma source to identify driving mechanisms that lead to surface changes. Depending on the exposure time and initial surface condition, the plasma strongly affects the surface in terms of work function and quantum efficiency (QE). For degraded Cs layers (work function >3 eV) a favorable increase in QE and reduction in work function can be achieved, while for Cs layers with an ultra-low work function of 1.2-1.3 eV the opposite is true. It is found that each plasma species can influence the Cs layers and that VUV photons lead to a work function increase of ultra-low work function layers. For sufficiently high VUV fluences a severe work function increase by 0.5 eV is given, highlighting the relevance of photochemical processes in the plasma-surface interaction and demonstrating that ultra-low work function layers are not stable in a hydrogen plasma environment. Negative hydrogen ion source Neutral beam injection Plasma-surface interaction Caesium Work function Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 17 Oct, 2024 Reviews received at journal 16 Oct, 2024 Reviews received at journal 01 Oct, 2024 Reviews received at journal 28 Sep, 2024 Reviewers agreed at journal 13 Sep, 2024 Reviewers agreed at journal 13 Sep, 2024 Reviewers agreed at journal 10 Sep, 2024 Reviewers invited by journal 08 Sep, 2024 Editor assigned by journal 02 Sep, 2024 Submission checks completed at journal 02 Sep, 2024 First submitted to journal 30 Aug, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5003629","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":361292746,"identity":"f11a8f72-0825-40d2-9db0-738974fbb905","order_by":0,"name":"Adrian Heiler","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABE0lEQVRIiWNgGAWjYFCCBIYDYJKZuYGBoUICJsxMjBZGoJYzRGqBkkAtjG1wYdxa+NtzHx74uYMhj5+dsfFx5TyLPHMG7rSHXxis5XBpkTjz3OBg7xmGYslmxmbDs9skii0beLcbyzCkG+O05kYawwHeNobEDYcZ2yQbt0kkbjjAu01aguFwYgMOHfJALQf/ArXsP8zY/rNxDkJLPS4tBkAth8G2MDO2MTY2QLRIfmA4nIDLXYZnnjEclm2TSJxxmLFZsuEY0C/NQL8wGKQb4rJF7nga88e3bTaJ/f2HD35sqKnLM2fv3fbwR4W1PE7vQwA8BhkSDJgZ2Jh5DAhoQAYJQMVsjD9I0DEKRsEoGAXDHgAA2phZJHIGDSgAAAAASUVORK5CYII=","orcid":"","institution":"Max-Planck-Institut für Plasmaphysik","correspondingAuthor":true,"prefix":"","firstName":"Adrian","middleName":"","lastName":"Heiler","suffix":""},{"id":361292747,"identity":"0ce19ffe-2404-454b-a611-8b0a4a234e71","order_by":1,"name":"Roland Friedl","email":"","orcid":"","institution":"AG Experimentelle Plasmaphysik, Universität Augsburg","correspondingAuthor":false,"prefix":"","firstName":"Roland","middleName":"","lastName":"Friedl","suffix":""},{"id":361292748,"identity":"34412f22-e891-4fec-ba44-5a2f35f2720d","order_by":2,"name":"Ursel Fantz","email":"","orcid":"","institution":"Max-Planck-Institut für Plasmaphysik","correspondingAuthor":false,"prefix":"","firstName":"Ursel","middleName":"","lastName":"Fantz","suffix":""}],"badges":[],"createdAt":"2024-08-30 11:35:59","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5003629/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5003629/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":65823125,"identity":"0b5ee944-a0c9-42cd-adf1-195346693d89","added_by":"auto","created_at":"2024-10-03 08:04:28","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1115875,"visible":true,"origin":"","legend":"","description":"","filename":"PaperHeiler.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5003629/v1_covered_7a5c03f5-6d2a-46e4-a849-7ca566bbc8e4.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Separation of plasma species for investigating the impact of hydrogen plasmas on the work function of caesiated surfaces","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"plasma-chemistry-and-plasma-processing","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":" Learn more about [Plasma Chemistry and Plasma Processing](https://www.springer.com/journal/11090 ","snPcode":"11090","submissionUrl":"https://mc.manuscriptcentral.com/pcpp","title":"Plasma Chemistry and Plasma Processing","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Negative hydrogen ion source, Neutral beam injection, Plasma-surface interaction, Caesium, Work function","lastPublishedDoi":"10.21203/rs.3.rs-5003629/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5003629/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"In negative hydrogen ion sources in situ adsorption of Cs is typically used to generate low work function converter surfaces. 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