Analytic calculations of electron-nucleus bremsstrahlung cross sections above a few MeV including higher-order corrections and multiple scattering in the target

Autor(es)

Mangiarotti, A. ^[1] ; Martins, M. N. ^[1] ; Vanin, V. R. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Fis, Rua Matao 1371, BR-05508090 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIO; v. 446, p. 58-76, MAY 1 2019.
• Citações Web of Science: 1

Resumo

Calculations of the elementary process of electron-nucleus bremsstrahlung employing a partial-wave expansion of the initial and final electron wave functions are exact and offer results that match the experimental data, but they become impractical for increasingly higher electron energies, especially in some regions of the emitted photon phase space. Here we take the opposite approach and use analytic expressions based on the Olsen-Maximon-Wergeland additivity rule, valid above few MeV, to decouple the calculation of the screening and Coulomb corrections. The former is obtained from the first Born approximation, while the latter is evaluated within the formalism of the Furry-Sommerfeld-Maue wave functions using the leading-order expression by Elwert and Haug and the next-to-leading-order corrections by Roche, Ducos, and Proriol, which is presently the best way to calculate cross sections for electrons with energies in the range of hundreds of MeV. A detailed discussion of the approximations involved and an extensive comparison with experimental data have been published in previous works. Here we focus on the numerical procedures that have been developed and on the stringent cross checks that have been performed to ensure the accuracy of the results. Published benchmark calculations for bremsstrahlung in a pure Coulomb field, that stop at 100 keV, are extended here to 100 MeV by making available selected values that could be used by other independent researchers to validate their programs. We also discuss the numerical details of the procedure adopted to convolve the bremsstrahlung cross section with the impinging electron angular distribution due to multiple scattering in the target. (AU)

• Processo FAPESP: 16/13116-5 - Medidas sistemáticas do espalhamento múltiplo de elétrons e prótons com energias até 5 MEV
• Beneficiário: Alessio Mangiarotti
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 13/15634-5 - Estudo das propriedades do bremsstrahlung na faixa de energia de alguns MeV
• Beneficiário: Marcos Nogueira Martins
• Modalidade de apoio: Auxílio à Pesquisa - Pesquisador Visitante - Internacional