University of Hertfordshire

From the same journal

By the same authors

  • H. Y. Lan
  • W. Luo
  • Y. Xu
  • D. L. Balabanski
  • G. L. Guardo
  • M. La Cognata
  • D. Lattuada
  • C. Matei
  • R. G. Pizzone
  • T. Rauscher
  • J. L. Zhou
View graph of relations
Original languageEnglish
Article number044618
JournalPhysical Review C
Volume105
Issue4
DOIs
Publication statusPublished - 27 Apr 2022
Externally publishedYes

Abstract

In the environment of a hot plasma, as achieved in stellar explosions, capture and photodisintegration reactions proceeding on excited states in the nucleus can considerably contribute to the astrophysical reaction rate. Usually, such reaction rates including the excited-state contribution are obtained from theoretical calculations as the direct experimental determination of these astrophysical rates is currently unfeasible. Future experiments could provide constraining information on the current reaction models which would improve the predictive power of the theoretical reaction rates. In the present study, experiments of photodisintegration with charged-particle emission leading to specific excited states in the residual nucleus are proposed. The expected experimental results can be used to determine the particle-Transmission coefficients in the model calculations of photodisintegration and capture reactions. With such constrained transmission coefficients, the astrophysical reaction rates especially involving the excited-state contributions can be better predicted and implemented in astrophysical simulations. In particular, (γ,p) and (γ,α) reactions in the mass and energy range relevant to the astrophysical p process are considered and the feasibility of measuring them with the ELISSA detector system at the future Variable Energy γ-ray (VEGA) facility at Extreme Light Infrastructure-Nuclear Physics is investigated. To this end, in a first step 17 reactions with proton emission and 17 reactions with α emission are selected and the dependence of calculated partial cross sections on the variation of nuclear property input is tested. The simulation results reveal that, for the (γ,p) reaction on 12 targets of Si29, Fe56,Se74,Sr84,Zr91,Ru96,98,Pd102,Cd106, and Sn115,117,119, and the (γ,α) reaction on five targets of V50,Sr87,Te123,125, and Sm149, the yields of the reaction channels with the transitions to the excited states in the residual nucleus, namely (γ,Xi) with i≠0, are relevant and even dominant. Therefore, these 17 reactions are considered in the further feasibility study. For each of the 17 photon-induced reactions, in order to attain the detectable limit of 100 counts per day for the total proton or α-particle yields, the minimum required γ-beam energies Elow for the measurements are estimated. It is further found that for each considered reaction, the total yields of the charged-particle X may be dominantly contributed from one, two, or three (γ,Xi) channels within a specific, narrow energy range of the incident γ beam. If the actual measurements of these photon-induced reactions are performed in this energy range, the sum of the yields of the dominant (γ,Xi) channels can be approximated by the measured yields of the charged particle X within acceptable uncertainty. This allows to experimentally obtain the yields of the (γ,Xi) channels which dominantly contribute to the total yields of X. Using the simulated yields, these energy ranges for each of the 17 photon-induced reactions are derived. Furthermore, the energy spectra of the (γ,Xi) channels with 0≤i≤10 are simulated for each considered reaction, with the incident γ-beam energies in the respective energy range as derived before. Based on the energy spectra, the identification of the individual dominant (γ,Xi) channels is discussed. It becomes evident that measurements of the photon-induced reactions with charged-particle emissions considered in this work are feasible with the VEGA+ELISSA system and will provide knowledge useful for nuclear astrophysics.

Notes

Funding Information: This work is supported by the National Natural Science Foundation of China (Grant No. 11675075). This work is carried out under the contract PN 19 06 01 05 sponsored by the Romanian Ministry of Research and Innovation. Y.X., D.L.B., and C.M. acknowledge supports from the ELI-RO program funded by the Institute of Atomic Physics (Magurele, Romania) under Contract No. ELI_15/16.10.2020 and from the Extreme Light Infrastructure Nuclear Physics (ELI-NP) Phase II, a project co-financed by the Romanian Government and the European Union through the European Regional Development Fund—the Competitiveness Operational Programme (1/07.07.2016, COP, ID 1334). T.R. is partially supported by the European COST action “ChETEC” (CA16117). This work was financially supported by the Italian Ministry of Education, University and Research, PON R&I 2014-2020 - AIM, project AIM1848704-3. Publisher Copyright: © 2022 American Physical Society.

ID: 27408958