[PDF]    https://doi.org/10.3952/physics.2024.64.1.5

Open access article / Atviros prieigos straipsnis
Lith. J. Phys. 64, 48–57 (2024)

NUMERICAL SIMULATION OF PROTON BACKSCATTERING SPECTRA IN GEANT4 TOOLKIT
Danielius Lingis, Mindaugas Gaspariūnas, Vitalij Kovalevskij, Artūras Plukis, and Vidmantas Remeikis
Center for Physical Sciences and Technology, Savanorių 231, 02300 Vilnius, Lithuania
Email: danielius.lingis@ftmc.lt

Received 15 May 2023; accepted 3 October 2023

Rutherford backscattering spectroscopy (RBS) is a widely used technique for the atomic-scale analysis of sample composition, lattice displacement and impurity profiling. RBS is based on the elastic scattering of incident charged particles by target nuclei and the subsequent detection of scattered particles. The interpretation of RBS spectra, however, poses challenges due to overlapping peaks, corresponding to scattering from different atomic species, and uncertainties from energy loss, scattering geometry and detector response. To address this, an open source simulation model based on the versatile GEANT4 simulation toolkit has been developed. The flexibility of the open source enables users to tailor the model to its specific requirements, such as the use of specific particle stopping powers, cross-sections, and physics processes. This work presents the results of the comparison between the experimental and simulated backscattering spectra in crystalline silicon, silicon carbide and silicon dioxide samples by 1–2.5 MeV energy protons, obtained in random orientation conditions. The results demonstrate the capability of the model to accurately simulate backscattering spectra in both amorphous materials and single crystals. The overall agreement between the simulated and experimental results is highly promising for future development and use in the interpretation and simulation of RBS spectra.
Keywords: Rutherford backscattering, GEANT4 simulations, backscattering spectra, protons
PACS: 82.80.Yc, 25.40.Cm

PROTONŲ ATGALINĖS SKLAIDOS SPEKTRŲ SKAITINIS MODELIAVIMAS GEANT4 PROGRAMINIU PAKETU
Danielius Lingis, Mindaugas Gaspariūnas, Vitalij Kovalevskij, Artūras Plukis, Vidmantas Remeikis

Fizinių ir technologijos mokslų centras, Vilnius, Lietuva
Rezerfordo atgalinės sklaidos spektroskopija (angl. Rutherford Backscattering Spectroscopy, RBS) yra metodika, plačiai naudojama bandinių sudėties, kristalinių gardelių pažaidų ir priemaišų profiliavimo analizėse. Metodika paremta į bandinį krintančių jonų elastine sklaida ir atgal išsklaidytų dalelių energinio spektro registravimu detektoriumi. Tačiau atgalinės sklaidos spektrų interpretavimas sukelia sunkumų dėl persiklojančių smailių, atitinkančių sklaidą nuo skirtingų atomų, ir sklaidos geo­metrijos, energijos nuostolių bei detektoriaus atsako neapibrėžčių. Siekiant palengvinti spektrų interpretavimo procesą, buvo sukurtas atviro kodo skaitinio modeliavimo pavyzdys, paremtas universaliu GEANT4 skaitinio modeliavimo programiniu paketu. Atviro kodo modelio lankstumas leidžia naudotojams pritaikyti modelį savo tikslams – nuo galimybės naudoti įvairias dalelių stabdomųjų gebų ir reakcijų skerspjūvių bibliotekas bei modifikuoti fizikinius procesus iki galimybės sekti dalelių parametrus. Šio darbo metu pristatyti eksperimentinių ir skaitiškai modeliuotų atgalinės sklaidos spektrų palyginimo rezultatai, gauti naudojant 1–2,5 MeV energijos protonų pluoštelį kristalinio silicio, silicio karbido ir silicio dioksido bandiniuose atsitiktinės orientacijos geomet­rijoje, kuri praktiškai atitinka amorfinių medžiagų atvejį. Pateikti rezultatai rodo, kad modelis geba tiksliai skaitiškai atkartoti atgalinės sklaidos spektrus nuo amorfinių ir kristalinių medžiagų. Nors ideali atitiktis eksperimentiniams spektrams nebuvo gauta visais atvejais, bendras spektrų atitikimas rodo, kad modelį galima toliau tobulinti ir naudoti RBS metodikoje.



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