Národní úložiště šedé literatury Nalezeno 5 záznamů.  Hledání trvalo 0.01 vteřin. 
First measurement of the O-18(p, alpha)N-15 cross section at astrophysical energies
La Cognata, M. ; Spitaleri, C. ; Mukhamedzhanov, A. ; Tribble, R. E. ; Al-Abdullah, T. ; Banu, A. ; Cherubini, S. ; Coc, A. ; Crucilla, V. ; Goldberg, V. ; Gulino, M. ; Irgaziev, B. ; Kiss, G. G. ; Lamia, L. ; Mrázek, Jaromír ; Pizzone, R. G. ; Puglia, S. M. R. ; Rapisarda, G. G. ; Romano, S. ; Sergi, M. L. ; Tabacaru, G. ; Trache, L. ; Trzaska, W. ; Tudisco, S. ; Tumino, A.
The O-18(p, alpha)N-15 reaction rate has been deduced by means of the Trojan horse method. For the first time the contribution of the 20 keV resonance has been directly evaluated, giving a value about 35% larger than the one in the literature. Moreover, the present approach has allowed to improve the accuracy by a factor 8.5, as it is based on the measured strength instead of spectroscopic measurements. The contribution of the 90 keV resonance has been also determined, which turned out to be of negligible importance to astrophysics.
Astrophysical Reaction Rates Obtained By Indirect Techniques
Tribble, R. E. ; Al-Abdullah, T. ; Alharbi, A. ; Aysto, J. ; Banu, A. ; Burjan, Václav ; Carstoiu, F. ; Chen, X. ; Clark, H. L. ; Davidson, T. ; Fu, C. ; Gagliardi, C. A. ; Hardy, J. C. ; Iacob, V. E. ; Jokinen, J. ; Kroha, Václav ; Lui, Y. W. ; McCleskey, M. ; Mukhamedzhanov, A. ; Nica, N. ; Park, H. ; Roeder, B. T. ; Saastamoinen, A. ; Simmons, E. ; Tabacaru, G. ; Tokimoto, Y. ; Trache, L. ; Woods, P. J. ; Zhai, Y.
ndirect techniques have been used to obtain information about reaction rates for several proton capture reactions that occur on short-lived nuclei. The techniques used to carry out the measurements are reviewed and the results obtained are presented. Also future prospects for further measurements with a new facility, T-REX, are discussed.
High accuracy O-18(p, alpha)N-15 reaction rate in the 8 . 10(6)-5 . 10(9) K temperature range
La Cognata, M. ; Spitaleri, C. ; Mukhamedzhanov, A. ; Banu, A. ; Cherubini, S. ; Coc, A. ; Crucilla, V. ; Goldberg, V. ; Gulino, M. ; Irgaziev, B. ; Kiss, G. G. ; Lamia, L. ; Mrázek, Jaromír ; Pizzone, R. G. ; Puglia, S. M. R. ; Rapisarda, G. G. ; Romano, S. ; Sergi, M. L. ; Tabacaru, G. ; Trache, L. ; Tribble, R. E. ; Trzaska, W. ; Tumino, A.
The O-18(p, alpha)N-15 reaction is of great importance in several astrophysical scenarios, as it influences the production of key isotopes such as F-19, O-18 and N-15. In this work, a high accuracy O-18(p, alpha) N-15 reaction rate is proposed, based on the simultaneous fit of direct measurements and of the results of a new Trojan Horse experiment. In particular, we have focused on the study of the broad 660 keV 1/2(+) resonance. Since Gamma similar to 100 - 300 keV, it strongly influences the nearly-zero-energy region of the cross section by means of the low-energy tail of the resonant contribution and dominates the cross section at higher energies. Here we provide a factor of 2 larger reaction rate above T similar to 0.510(9) K based over our new improved determination of its resonance parameters.

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