Exploring the origin of the rarest stable isotopes naturally occurring on Earth with real photon beams

Department of Physics and Astronomy, James Madison University, Harrisonburg, VA 22807, USA

^* Corresponding author: banula@jmu.edu

Published online: 11 July 2025

Abstract

This lecture brings into focus research work that aims to advance fundamental knowledge on a forefront topic in nuclear astrophysics – the nucleosynthesis beyond Fe of the rarest stable isotopes naturally occurring on Earth (the origin of p-nuclei). The astrophysical phenomenon responsible for this synthesis is termed the p-process. Though modelling the p-process nucleosynthesis is a daunting task, significant progress can be made by performing key experimental studies, which can constrain Hauser-Feshbach statistical nuclear models used to calculate the many unknown astrophysically relevant stellar reaction rates. Photodisintegration stellar reactions play a major role in the p-process; they are especially highly sensitive to the low-energy tail of the nuclear photon strength function (PSF). Recent experimental efforts to constrain pSFs for the p-process nucleosynthesis calculations using real photons at the HIγS/TUNL facility and at the Madison Accelerator Laboratory (MAL), an unconventional bremsstrahlung facility that features a repurposed medical electron linear accelerator, will be discussed in this lecture.