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Parameterization of Direct and Doorway Processes in R-Matrix Formalism

Conference ·
 [1];  [1];  [1];  [2];  [3];  [4];  [3]
  1. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
  2. OECD Nuclear Energy Agency, Paris (France)
  3. Rensselaer Polytechnic Institute, Troy, NY (United States)
  4. Naval Nuclear Laboratory, Schenectady, NY (United States)
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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 Institute, 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 Type:
Conference paper
Conference Information:
15. International Conference on Nuclear Data for Science and Technology (ND2022), Held Virtually, 21-29 Jul 2023
https://indico.frib.msu.edu/event/52/overview
Country of Publication:
United States
Language:
English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
Brune’s Alternative R-Matrix Parameters
Compound Nuclear (CN) Resonant Reactions
Doorway
Nuclear Criticality Safety Program (NCSP)
R-Matrix
R-Matrix Formalism