Methodology for measuring photonuclear reaction cross sections with an electron accelerator based on Bayesian analysis

Saverio Braccini; Pierluigi Casolaro; Gaia Dellepiane; Christian Kottler; Matthias Lüthi; Lorenzo Mercolli; Peter Peier; Paola Scampoli; Andreas Türler

doi:10.1016/j.apradiso.2024.111275

Methodology for measuring photonuclear reaction cross sections with an electron accelerator based on Bayesian analysis

Appl Radiat Isot. 2024 Jun:208:111275. doi: 10.1016/j.apradiso.2024.111275. Epub 2024 Mar 2.

Authors

Saverio Braccini¹, Pierluigi Casolaro², Gaia Dellepiane¹, Christian Kottler³, Matthias Lüthi⁴, Lorenzo Mercolli⁵, Peter Peier³, Paola Scampoli⁶, Andreas Türler⁷

Affiliations

¹ Albert Einstein Center for Fundamental Physics (AEC), Laboratory for High Energy Physics (LHEP), University of Bern, 3012, Bern, Switzerland.
² Albert Einstein Center for Fundamental Physics (AEC), Laboratory for High Energy Physics (LHEP), University of Bern, 3012, Bern, Switzerland; Department of Physics "Ettore Pancini", University of Napoli Federico II, Complesso Universitario di Monte S. Angelo, 80126, Napoli, Italy; INFN Naples Unit, Naples, Italy. Electronic address: pierluigi.casolaro@unina.it.
³ Federal Institute of Metrology METAS, 3003, Bern-Wabern, Switzerland.
⁴ Federal Institute of Metrology METAS, 3003, Bern-Wabern, Switzerland; Department of Chemistry, Biochemistry, and Pharmaceutical Sciences (DCBP), University of Bern, 3012, Bern, Switzerland. Electronic address: matthias.luethi@metas.ch.
⁵ Albert Einstein Center for Fundamental Physics (AEC), Laboratory for High Energy Physics (LHEP), University of Bern, 3012, Bern, Switzerland; Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, 3010, Bern, Switzerland.
⁶ Albert Einstein Center for Fundamental Physics (AEC), Laboratory for High Energy Physics (LHEP), University of Bern, 3012, Bern, Switzerland; Department of Physics "Ettore Pancini", University of Napoli Federico II, Complesso Universitario di Monte S. Angelo, 80126, Napoli, Italy.
⁷ Department of Chemistry, Biochemistry, and Pharmaceutical Sciences (DCBP), University of Bern, 3012, Bern, Switzerland.

PMID: 38484591
DOI: 10.1016/j.apradiso.2024.111275

Abstract

Accurate measurements of photonuclear reaction cross sections are crucial for a number of applications, including radiation shielding design, absorbed dose calculations, reactor physics and engineering, nuclear safeguard and inspection, astrophysics, and nuclear medicine. Primarily motivated by the study of the production of selected radionuclides with high-energy photon beams (mainly ²²⁵Ac, ⁴⁷Sc, and ⁶⁷Cu), we have established a methodology for the measurement of photonuclear reaction cross sections with the microtron accelerator available at the Swiss Federal Institute of Metrology (METAS). The proposed methodology is based on the measurement of the produced activity with a High Purity Germanium (HPGe) spectrometer and on the knowledge of the photon fluence spectrum through Monte Carlo simulations. The data analysis is performed by applying a Bayesian fitting procedure to the experimental data and by assuming a functional trend of the cross section, in our case a Breit-Wigner function. We validated the entire methodology by measuring a well-established photonuclear cross section, namely the ¹⁹⁷Au(γ, n)¹⁹⁶Au reaction. The results are consistent with those reported in the literature.

Keywords: Bayesian analysis; Cross section; Electron accelerator; Photonuclear reactions.