Background: Type I x-ray bursts are the most frequently observed thermonuclear explosions in the galaxy, resulting from thermonuclear runaway on the surface of an accreting neutron star. The S30(Î±,p) reaction plays a critical role in burst models, yet insufficient experimental information is available to calculate a reliable, precise rate for this reaction. Purpose: Our measurement was conducted to search for states in Ar34 and determine their quantum properties. In particular, natural-parity states with large Î±-decay partial widths should dominate the stellar reaction rate. Method: We performed the first measurement of S30+Î± resonant elastic scattering up to a center-of-mass energy of 5.5 MeV using a radioactive ion beam. The experiment utilized a thick gaseous active target system and silicon detector array in inverse kinematics. Results: We obtained an excitation function for S30(Î±,Î±) near 150 in the center-of-mass frame. The experimental data were analyzed with R-matrix calculations, and we observed three new resonant patterns between 11.1 and 12.1 MeV, extracting their properties of resonance energy, widths, spin, and parity. Conclusions: We calculated the resonant thermonuclear reaction rate of S30(Î±,p) based on all available experimental data of Ar34 and found an upper limit about one order of magnitude larger than a rate determined using a statistical model. The astrophysical impact of these two rates has been investigated through one-zone postprocessing type I x-ray burst calculations. We find that our new upper limit for the S30(Î±,p)Cl33 rate significantly affects the predicted nuclear energy generation rate during the burst.
|Titolo:||First measurement of S 30 +Î± resonant elastic scattering for the S 30 (Î±,p) reaction rate|
|Data di pubblicazione:||2018|
|Citazione:||First measurement of S 30 +Î± resonant elastic scattering for the S 30 (Î±,p) reaction rate / Kahl, Daid; Yamaguchi, H.; Kubono, S.; Chen, A. A.; Parikh, A.; Binh, D. N.; Chen, J.; Cherubini, S.; Duy, N. N.; Hashimoto, T.; Hayakawa, S.; Iwasa, N.; Jung, H. S.; Kato, S.; Kwon, Y. K.; Nishimura, S.; Ota, S.; Setoodehnia, K.; Teranishi, T.; Tokieda, H.; Yamada, T.; Yun, C. C.; Zhang, L. Y.. - In: PHYSICAL REVIEW C. - ISSN 2469-9985. - 97:1(2018).|
|Appare nelle tipologie:||1.1 Articolo in rivista|