Deposition and Performance of Depth-Graded W/Si Multilayers on Silicon Pore Optics for the WXPT Mission

Deposition and Performance of Depth-Graded W/Si Multilayers on Silicon Pore Optics for the WXPT Mission | 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 Deposition and Performance of Depth-Graded W/Si Multilayers on Silicon Pore Optics for the WXPT Mission Zeying Cai, Zhuo Li, Zhengwei Li, Jun Xiong, Liqiang Qi, Zhongliang Li, and 11 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9091840/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 6 You are reading this latest preprint version Abstract The development of high-performance depth-graded multilayer coatings is critical for next-generation hard X-ray astronomical telescopes, such as the proposed Wide-band X-ray Polarization Telescope (WXPT) mission. This work focuses on the fabrication and performance evaluation of W/Si depth-graded multilayers designed for WXPT. The coatings were deposited using a custom-built linear direct-current magnetron sputtering system. Grazing-incidence X-ray reflectometry (XRR) and cross-sectional transmission electron microscopy (TEM) revealed consistently smooth interfaces with widths of approximately 0.3-0.4 nm, demonstrating exceptional layer uniformity and minimal cumulative roughening even over hundreds of layers. Atomic force microscopy confirmed the ultra-smooth surface morphology (RMS roughness \((<)\) 0.3 nm) of the final coatings. The critical impact of substrate roughness on multilayer reflectivity was quantitatively demonstrated. Most importantly, hard X-ray reflectivity measurements, both from a laboratory source and synchrotron radiation, showed excellent agreement with theoretical simulations assuming an interface width of \((\sigma)\) = 0.4 nm. The coatings achieved high reflectivity across a broad energy band (e.g.,25% at 20-30 keV for a design optimized for 0.3 \((^\circ)\) incidence), successfully meeting the performance targets. These results establish a robust and reliable fabrication pathway for producing high-quality W/Si multilayers, marking a significant step towards their application in SPO for the WXPT mission. Depth-graded multilayers W/Si multilayers Silicon pore optics X-ray optics Wideband X-ray telescope Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 10 Apr, 2026 Reviewers agreed at journal 13 Mar, 2026 Reviewers invited by journal 12 Mar, 2026 Editor assigned by journal 12 Mar, 2026 Submission checks completed at journal 11 Mar, 2026 First submitted to journal 11 Mar, 2026 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-9091840","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":605649372,"identity":"a49e42ae-f72d-414c-8440-37d4670eb0f6","order_by":0,"name":"Zeying Cai","email":"","orcid":"","institution":"Chinese Academy of Sciences","correspondingAuthor":false,"prefix":"","firstName":"Zeying","middleName":"","lastName":"Cai","suffix":""},{"id":605649374,"identity":"ee131f91-0d62-47de-935e-8726c2201a6d","order_by":1,"name":"Zhuo Li","email":"","orcid":"","institution":"Chinese Academy of 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This work focuses on the fabrication and performance evaluation of W/Si depth-graded multilayers designed for WXPT. The coatings were deposited using a custom-built linear direct-current magnetron sputtering system. Grazing-incidence X-ray reflectometry (XRR) and cross-sectional transmission electron microscopy (TEM) revealed consistently smooth interfaces with widths of approximately 0.3-0.4 nm, demonstrating exceptional layer uniformity and minimal cumulative roughening even over hundreds of layers. Atomic force microscopy confirmed the ultra-smooth surface morphology (RMS roughness \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\((\u0026lt;)\\)\u003c/span\u003e\u003c/span\u003e 0.3 nm) of the final coatings. The critical impact of substrate roughness on multilayer reflectivity was quantitatively demonstrated. 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These results establish a robust and reliable fabrication pathway for producing high-quality W/Si multilayers, marking a significant step towards their application in SPO for the WXPT mission.\u003c/p\u003e","manuscriptTitle":"Deposition and Performance of Depth-Graded W/Si Multilayers on Silicon Pore Optics for the WXPT Mission","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-17 19:05:30","doi":"10.21203/rs.3.rs-9091840/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-04-10T12:54:04+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"222014294128646262972244586285540759983","date":"2026-03-13T12:07:11+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-03-12T09:51:03+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-12T05:30:58+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-11T11:55:41+00:00","index":"","fulltext":""},{"type":"submitted","content":"Experimental Astronomy","date":"2026-03-11T08:07:15+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"experimental-astronomy","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"expa","sideBox":"Learn more about [Experimental Astronomy](http://link.springer.com/journal/10686)","snPcode":"10686","submissionUrl":"https://submission.nature.com/new-submission/10686/3","title":"Experimental Astronomy","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"7c70c49d-4212-47bc-a332-e3ed34608814","owner":[],"postedDate":"March 17th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-03-17T19:05:30+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-17 19:05:30","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9091840","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9091840","identity":"rs-9091840","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}