2026-04-13T13:12:48Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/2264032026-04-08T16:24:09Zcom_2072_1057col_2072_478823col_2072_478917

On the relativistic impulse approximation for the calculation of Compton scattering cross sections and photon interaction coefficients used in kV dosimetry Wang, X.J. Miguel, Beatriz Seuntjens, J. Fernández Varea, José María Fotons Dosimetria (Radiació) Transferència d'energia Grafit Photons Radiation dosimetry Energy transfer Graphite <p>We calculate differential and integrated cross sections for the Compton interaction as well as mass</p><p>attenuation (μC/ρ), mass energy-transfer (μC</p><p>tr/ρ), and mass energy-absorption (μen/ρ)</p><p>coefficients, within the relativistic impulse approximation (RIA) using Compton profiles (CPs)</p><p>obtained from unrestricted Hartree–Fock electron densities. We investigate the impact of using</p><p>molecular as opposed to atomic CPs on dosimetric photon interaction coefficients for air, water</p><p>and graphite, and compare our cross sections to the simpler Waller–Hartree (WH) and</p><p>Klein–Nishina (KN) formalisms. We find that differences in μC/ρ and μC</p><p>tr/ρ resulting from the</p><p>choice of CPs within the RIA are small relative to the differences between the RIA, WH, and KN</p><p>calculations. Surprisingly, although the WH binding corrections seem accurate when considering</p><p>μC/ρ, there are significant discrepancies between the WH and RIA results when we look at μC</p><p>tr/ρ.</p><p>The WH theory can differ substantially from the predictions of KN and the RIA in the tens of keV</p><p>range (e.g. 6%–10% at 20 keV), when Compton scattering becomes the dominant interaction</p><p>mechanism. For lower energies, the disagreement further grows to about one order of magnitude</p><p>at 1 keV. However, since the photoelectric effect transfers more energy than the Compton</p><p>interaction in the tens of keV range and below, the differences in the total μen/ρ values resulting</p><p>from the choice of Compton models (KN, WH, or RIA) are not larger than 0.4%, and the</p><p>differences between WH and the other two theories are no longer prominent.</p> 2026-01-29T13:14:29Z 2026-01-29T13:14:29Z 2020-01-01 2026-01-29T13:14:29Z info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion 0031-9155 https://hdl.handle.net/2445/226403 712759 eng Versió postprint del document publicat a: https://doi.org/10.1088/1361-6560/ab8108 Physics in Medicine and Biology, 2020, vol. 65, p. 125010-1-125010-16 https://doi.org/10.1088/1361-6560/ab8108 (c) ART AMB B, 2020 info:eu-repo/semantics/openAccess 16 p. application/pdf ART AMB B Articles publicats en revistes (Física Quàntica i Astrofísica)