Direct determination of the astrophysical reaction rate of ¹⁴¹Pr(γ,\,n)¹⁴⁰Pr at the SSRF-SLEGS

The 141 Pr(γ,,n) cross-section is critical to the nucleosynthesis of p-nuclides ¹36,138Ce in thermonuclear supernovae and in massive stars. The photonuclear reaction of ¹41Pr(γ,,n) s a new method for producing^ 140 Pr radioisotopes for positron emission tomography tracing in nuclear medicine. We aim to perform an accurate measurement of the 141 Pr(γ$,,n)^140Pr cross-section over a sufficiently wide range of gamma energies of the p-process and deduce the ^140Pr(n,,γ)^141Pr cross-section with γSF and TALYS-SMLO models. We determined the astrophysical reaction rate of ^141Pr(γ,,n)^140Pr at the temperature range of 0.2-10,GK based on the new measurement cross-section of the 140 Pr reaction. We performed a new measurement of the 141 Pr photoneutron cross-section at the Shanghai Laser Electron Gamma Source of the Shanghai Synchrotron Radiation Facility using quasi-monoenergetic laser Compton scattered γ-ray beam s . The neutrons emitted by the ^141Pr target were detected by the flat-efficiency detector array, while the γbeam transmitted by the ¹41Pr target were attenuated by a copper absorber and then measured by a bismuth germanate detector in order to reconstruct theγ spectrum incident on the target. The cross-section data of 141 Pr(γ$,,n) were acquired using an unfolding iteration method with an uncertainty of less than 4%, and the inconsistencies between the available experimental data and evaluation libraries were discussed. The inverse reaction cross-section of ^140Pr(n,,γ) and the reaction rates for the ^141Pr(γ,,n) reaction were derived over the astrophysically relevant temperature range of the p-process nucleosynthesis model. The photodisintegration decay constants of the ^141Pr(γ,,n) reaction for stellar temperatures between 0.2,GK and 10,GK are provided in a tabular form and by an analytical fitting expression. The λ_ γ n (^ 141 Pr ) = 0.013 ± 0.001, s ^ -1 at a typical p-process temperature of $T=2.5,GK was also computed. The photodisintegration decay constants of the 141 Pr(γ,,n) reaction deviate significantly from previous theoretical predictions, and the uncertainties are significantly reduced in the direct measurement.