Gamma-Ray Attenuation and Spectral-Angular Transport in Transparent Graded-Z Multilayer Shields

Gamma-Ray Attenuation and Spectral-Angular Transport in Transparent Graded-Z Multilayer Shields | 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 Article Gamma-Ray Attenuation and Spectral-Angular Transport in Transparent Graded-Z Multilayer Shields S. Alsalmi This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8510415/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 12 You are reading this latest preprint version Abstract Transparent radiation shields that combine efficient photon attenuation with controlled secondary emission are of interest for medical imaging, nuclearmedicine, scientific instrumentation, and radiation-monitoring environments. In this study, a transparent graded-Z multilayer shield composed of bismuth-rich borosilicate (BBS), lutetium aluminium garnet (LuAG), and silica (SiO2) is investigated using Geant4 Monte Carlo simulations and compared with commercial RS-253 glass at matched areal density. The graded-Z architecture exhibits higher mass attenuation coefficients, shorter mean free paths, and smaller half-value layers over the photon energy range 0.06-1.33~MeV, indicating enhanced attenuation efficiency without increased thickness. Secondary-photon spectra reveal energy-dependent fluorescence governed by the staggered K-edges of Lu and Bi, while fluorescence yield decreases at higherenergies as Compton scattering becomes dominant. Angular analysis shows forward-peaked transmission for both materials, with the graded-Z multilayerdirecting a larger fraction of transmitted energy into the forward direction. These results demonstrate that graded-Z shielding redistributes photontransport spectrally and directionally, offering tunable performance while not always minimizing forward energy leakage. To the best of our knowledge, this work provides the first quantitative implementation of the graded-Z shielding concept in fully transparent glass-based materials while jointly resolving secondary gamma-ray energy spectra and angular photon transport. The results demonstrate that transparent graded-Z shields actively redistribute photon propagation spectrally and directionally, and establish spectral-angular scoring as an essential metric for evaluating next-generation transparent radiation-shielding windows. Physical sciences/Materials science Physical sciences/Optics and photonics Physical sciences/Physics Geant4 simulation Mass attenuation coefficient Gamma-ray shielding Monte Carlo method Transparent shielding Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 23 Feb, 2026 Reviews received at journal 21 Feb, 2026 Reviewers agreed at journal 02 Feb, 2026 Reviewers agreed at journal 31 Jan, 2026 Reviews received at journal 25 Jan, 2026 Reviewers agreed at journal 08 Jan, 2026 Reviewers agreed at journal 08 Jan, 2026 Reviewers invited by journal 07 Jan, 2026 Editor invited by journal 06 Jan, 2026 Editor assigned by journal 05 Jan, 2026 Submission checks completed at journal 05 Jan, 2026 First submitted to journal 04 Jan, 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-8510415","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":571478105,"identity":"8ce749fa-fe8b-443b-b6f0-47106911fd10","order_by":0,"name":"S. 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In this study, a transparent graded-Z multilayer shield composed of bismuth-rich borosilicate (BBS), lutetium aluminium garnet (LuAG), and silica (SiO2) is investigated using Geant4 Monte Carlo simulations and compared with commercial RS-253 glass at matched areal density. The graded-Z architecture exhibits higher mass attenuation coefficients, shorter mean free paths, and smaller half-value layers over the photon energy range 0.06-1.33~MeV, indicating enhanced attenuation efficiency without increased thickness. Secondary-photon spectra reveal energy-dependent fluorescence governed by the staggered K-edges of Lu and Bi, while fluorescence yield decreases at higherenergies as Compton scattering becomes dominant. Angular analysis shows forward-peaked transmission for both materials, with the graded-Z multilayerdirecting a larger fraction of transmitted energy into the forward direction. These results demonstrate that graded-Z shielding redistributes photontransport spectrally and directionally, offering tunable performance while not always minimizing forward energy leakage. To the best of our knowledge, this work provides the first quantitative implementation of the graded-Z shielding concept in fully transparent glass-based materials while jointly resolving secondary gamma-ray energy spectra and angular photon transport. 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