Measurement of the ${}_7\mathrm{Li}(\gamma ,t){}_4\mathrm{He}$ ground-state cross section between $E_{\gamma }=4.4$ and 10 MeV

Journal Article · 14 May 2020 · Physical Review C

DOI: https://doi.org/10.1103/physrevc.101.055801 · OSTI ID:1658871

Munch, M. ^[1]; Matei, C.  ^[2]; Pain, S. D. ^[3]; Febbraro, M. T. ^[3]; Chipps, K. A. ^[3]; Karwowski, H. J. ^[4]; Diget, C. Aa. ^[5]; Pappalardo, A. ^[2]; Chesnevskaya, S. ^[2]; Guardo, G. L. ^[6]; Walter, D. ^[7]; Balabanski, D. L. ^[2]; Becchetti, F. D. ^[8]; Brune, C. R. ^[9]; Chae, K. Y. ^[10]; Frost-Schenk, J. ^[5]; Kim, M. J. ^[10]; Kwag, M. S. ^[10]; La Cognata, M. ^[11]; Lattuada, D. ^[2] ; Pizzone, R. G. ^[11]; Rapisarda, G. G. ^[11]; Turturica, G. V. ^[2]; Ur, C. A. ^[2]; Xu, Y. ^[2]

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1. Aarhus Univ. (Denmark). Dept. of Physics and Astronomy; Univ. of York (United Kingdom). Dept. of Physics
2. Horia Hulubei National Inst. for R&D in Physics and Nuclear Engineering, Bucharest-Magurele (Romania). Extreme Light Infrastructure - Nuclear Physics
3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
4. Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Physics; Duke Univ., Durham, NC (United States). Triangle Universities Nuclear Laboratory
5. Univ. of York (United Kingdom). Dept. of Physics
6. Horia Hulubei National Inst. for R&D in Physics and Nuclear Engineering, Bucharest-Magurele (Romania). Extreme Light Infrastructure - Nuclear Physics; Istituto Nazionale di Fisica Nucleare (INFN), Catania (Italy). Lab. Nazionali del Sud (INFN-LNS)
7. Rutgers Univ., New Brunswick, NJ (United States). Dept. of Physics and Astronomy
8. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Physics
9. Ohio Univ., Athens, OH (United States)
10. Sungkyunkwan Univ., Suwon (Republic of Korea). Dept. of Physics
11. Istituto Nazionale di Fisica Nucleare (INFN), Catania (Italy). Lab. Nazionali del Sud (INFN-LNS)

Here, the ${}_7\mathrm{Li}(\gamma ,t){}_4\mathrm{He}$ ground state cross section was measured for the first time using monoenergetic $\gamma$ rays with energies between 4.4 and 10 MeV at the High Intensity Gamma-ray Source. The reaction is important for the primordial Li problem and for testing our understanding of the mirror $\alpha$-capture reactions ${}_3\mathrm{H}(\alpha ,\gamma ){}_7\mathrm{Li}$ and ${}_3\mathrm{He}(\alpha ,\gamma ){}_7\mathrm{Be}$. Although over the last 30 years most measurements of the ${}_3\mathrm{H}(\alpha ,\gamma ){}_7\mathrm{Li}$ reaction have concentrated in an energy range below $E_{\gamma }=3.65$ MeV, measurements at higher energies could potentially restrict the extrapolation to astrophysically important energies. The experimental arrangement for measuring the ${}_7\mathrm{Li}(\gamma ,t){}_4\mathrm{He}$ reaction included a large-area silicon detector array and several beam characterization instruments. The experimental astrophysical $S$ factor of ${}_3\mathrm{H}(\alpha ,\gamma )$ calculated from the present data was fitted using the $R$-matrix formalism. The results are in disagreement with previous experimental measurements in the same energy range but the extrapolated $S$ factor agrees with the potential model calculation and lower energy experimental data.

• Research Organization: University of North Carolina, Chapel Hill, NC (United States); Duke Univ., Durham, NC (United States). Triangle Universities Nuclear Laboratory
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP); USDOE National Nuclear Security Administration (NNSA); European Research Council (ERC); National Science Foundation (NSF); Science and Technology Facilities Council (STFC) (United Kingdom); National Research Foundation of Korea (NRF)
• Grant/Contract Number: FG02-97ER41033; FG02-97ER41041; AC05-00OR22725; FG02-88ER40387; NA0003883; NA0002132; LOEBNA-307447; PHY-1404218; ST/P003885/1; ST/L005727/1; NRF-2016R1A5A1013277; NRF-2018M7A1A1072274
• OSTI ID: 1658871
• Journal Information: Physical Review C, Vol. 101, Issue 5; ISSN 2469-9985
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English