Cross sections for neutron-induced reactions from surrogate data: revisiting the Weisskopf-Ewing approximation for \((n,n^{\prime})\) and \((n,2n)\) reactions

• Published in: arXiv.org
• Main Authors: Gorton, Oliver C, Escher, Jutta E
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 27.04.2023
• Subjects: Angular momentum; Approximation; Mathematical analysis; Nuclear cross sections; Nuclear reactions; Physics - Nuclear Experiment; Physics - Nuclear Theory
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2102.03452

Earlier work has demonstrated that cross sections for neutron-induced fission and radiative neutron capture can be determined from a combination of surrogate reaction data and theory. For the fission case, it was shown that Weisskopf-Ewing approximation, which significantly simplifies the implementation of the surrogate method, can be employed. Capture cross sections cannot be obtained, and require a detailed description of the surrogate reaction process. In this paper we examine the validity of the Weisskopf-Ewing approximation for determining unknown \((n,n^{\prime})\) and \((n,2n)\) cross sections from surrogate data. We find that peak cross sections can be estimated using the Weisskopf-Ewing approximation, but the shape of the \((n,n^{\prime})\) and \((n,2n)\) cross sections, especially for low neutron energies, cannot be reliably determined without accounting for the angular-momentum differences between the neutron-induced and surrogate reaction. To obtain reliable \((n,n^{\prime})\) and \((n,2n)\) cross sections from surrogate reaction data, a detailed description of the surrogate reaction mechanisms is required. To do so for the compound-nucleus energies and decay channels relevant to these reactions, it becomes necessary to extend current modeling capabilities.