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arXiv · 1604.08635

Statistical Hauser-Feshbach theory with width fluctuation correction including direct reaction channels for neutron induced reaction at low energies

T. Kawano·R. Capote·S. Hilaire
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Abstract

A model to calculate particle-induced reaction cross sections with statistical Hauser-Feshbach theory including direct reactions is given. The energy average of scattering matrix from the coupled-channels optical model is diagonalized by the transformation proposed by Engelbrecht and Weidenm\"{u}ller. The ensemble average of $S$-matrix elements in the diagonalized channel space is approximated by a model of Moldauer [Phys.Rev.C {\bf 12}, 744 (1975)] using newly parametrized channel degree-of-freedom $\nu_a$ to better describe the Gaussian Orthogonal Ensemble (GOE) reference calculations. Moldauer approximation is confirmed by a Monte Carlo study using randomly generated $S$-matrix, as well as the GOE three-fold integration formula. The method proposed is applied to the $^{238}$U(n,n') cross section calculation in the fast energy range, showing an enhancement in the inelastic scattering cross sections.

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T. Kawano, R. Capote, S. Hilaire. 2016-04-28. Statistical Hauser-Feshbach theory with width fluctuation correction including direct reaction channels for neutron induced reaction at low energies. https://doi.org/10.1103/physrevc.94.014612

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