14–19 Jun 2026
Monterey, California (USA)
US/Pacific timezone
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Constraining capture cross sections using proton inelastic scattering as a surrogate reaction

18 Jun 2026, 16:40
20m
Monterey, California (USA)

Monterey, California (USA)

Hilton Garden Inn Monterey
Oral Presentations Parallel

Speaker

Aaina Thapa (Lawrence Livermore national Laboratory)

Description

The surrogate reaction method is an alternative to direct measurements of compound nuclear reaction cross sections [1,2]. We introduce new theory tools for extracting capture cross sections from experiments that use proton inelastic scattering as a surrogate reaction mechanism. These extensions including two-step processes in populating the target nucleus in the proton inelastic scattering surrogate mechanism, Markov Chain Monte Carlo parameter inference for constraining the level density and gamma-ray strength function parameters, and accounting for the impact of partial-width fluctuations on the γ-emission probability due to the low-density of states available in competing particle emission channels. We apply these developments to 90Zr(p,p’γ) experimental data [3] to constrain the neutron capture cross section for 89Zr isotope which has a half-life of about 78 hours. We simultaneously determine the known proton capture cross section for 89Y as a benchmark for our approach.

References
[1] J. Escher et al. (2018). Phys. Rev. Lett. 121, 052501
[2] A. Ratkiewicz et al. (2019) Phys. Rev. Lett. 122, 052502.
[3] A. Thapa et al. (2025) arXiv:2511.03071
[4] S. Ota et al. (2015) Phys. Rev. C 92, 054603

Acknowledgements
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, with partial support from LDRD projects 20-ERD-030 and 19-ERD-017.

Contribution category Theory
Presenter status Faculty/Staff

Author

Aaina Thapa (Lawrence Livermore national Laboratory)

Co-authors

Jutta Escher (LLNL) Dr Emanuel Chimasnki (BNL) Dr Oliver Gorton (LLNL) Dr Marc Dupuis (CEA) Dr Eun Jin In (Louisiana State University) Dr Shuya Ota (BNL) Dr Sophie Péru (CEA) Dr Walid Younes (LLNL)

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