Nuclei in the Cosmos (NIC XVII)

Deep underground laboratory measurement of 13C(α,n)16O in the Gamow windows of the s- and i-processes

18 Sept 2023, 15:15

15m

Oral Underground nuclear astrophysics Underground nuclear astrophysics

Speaker

Dr Bingshui GAO (ON BEHALF OF THE JUNA COLLABORATION) (Institute of Modern Physics)

Description

The ${}^{13}$C($\alpha$,n)${}^{16}$O reaction is the main neutron source for the slow-neutron-capture (s-) process in Asymptotic Giant Branch stars and for the intermediate (i-) process. Direct measurements at astrophysical energies in above-ground laboratories are hindered by the extremely small cross sections and vast cosmic-ray induced background. We performed the first consistent direct measurement in the range of E${}_{\mathrm{c}.\mathrm{m}.}$ =0.24 MeV to 1.9 MeV using the accelerators at the China JinPing underground Laboratory (CJPL) and Sichuan University. Our measurement covers almost the entire i-process Gamow window in which the large uncertainty of the previous experiments has been reduced from 60% down to 15%, eliminates the large systematic uncertainty in the extrapolation arising from the inconsistency of existing data sets, and provides a more reliable reaction rate for the studies of the s- and i-processes along with the first direct determination of the $\alpha$-strength for the near-threshold state.

Presentation materials

6. NIC_BGao.pptx