Parameterization of Direct and Doorway Processes in R-Matrix Formalism
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- OECD Nuclear Energy Agency, Paris (France)
- Rensselaer Polytechnic Institute, Troy, NY (United States)
- Naval Nuclear Laboratory, Schenectady, NY (United States)
R-matrix formalism is extended beyond compound nuclear (CN) resonant reactions to include parameterization of direct as well as doorway processes. Direct processes in the R-matrix exterior are parameterized by a unitary matrix that introduces mixing among wave function coefficients of the incoming and outgoing wave function components at the R-matrix channel surface. Doorway processes are parameterized by separating the Hilbert space of the interior R-matrix region into its doorway and CN subspaces, from which doorway state eigenenergies, reduced width amplitudes, and the strengths of their coupling to CN levels appear as new R-matrix parameters. Parameterization of generalized as well as the conventional Reich–Moore approximation for eliminated capture channels in the presence of direct, doorway, and CN processes is presented along with a complex-valued scattering length with contributions from direct, doorway, and CN capture processes. Derivation of Brune’s alternative R-matrix parameters is extended to include doorway states. This work suggests how R-matrix formalism could be extended further by adopting the concepts from related reaction formalisms.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); OECD Nuclear Energy Agency, Paris (France); Rensselaer Polytechnic Inst., Troy, NY (United States); Naval Nuclear Laboratory, Schenectady, NY (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1994546
- Report Number(s):
- 186617
- Resource Relation:
- Conference: 15. International Conference on Nuclear Data for Science and Technology (ND2022), Held Virtually, 21-29 Jul 2023; Related Information: https://indico.frib.msu.edu/event/52/overview
- Country of Publication:
- United States
- Language:
- English
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