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HK: Physik der Hadronen und Kerne

HK 19: Kern- und Teilchen- Astrophysik II

HK 19.3: Vortrag

Dienstag, 20. März 2001, 15:00–15:15, F

Coulomb Dissociation of ⁸B at 254 A MeV — •F. Schümann¹, K. Behr², I. Böttcher³, A. Bruenle², K. Burkard², D. Cortina², A. Förster⁴, M. Gai⁵, H. Geissel², U. Greife⁶, F. Hammache², N. Iwasa⁷, P. Koczon², B. Kohlmeyer³, R. Kulessa⁸, H. Kumagai⁷, M. Menzel³, T. Motobayashi⁹, H. Oeschler⁴, A. Ozawa⁷, M. Ploskon⁸, E. Schwab², P. Senger², K. Sümmerer², Z. Sun², G. Surowka⁸, F. Uhlig⁴, A. Wagner¹⁰, and W. Walus⁸ — ¹Univ. Bochum — ²GSI Darmstadt — ³Univ. Marburg — ⁴TU Darmstadt — ⁵Univ. Connecticut — ⁶Colorado School of Mines — ⁷RIKEN Tokyo — ⁸Univ. Krakow — ⁹Rikkyo Univ. — ¹⁰FZ Rossendorf

Coulomb Dissociation (CD) of ⁸B is an alternative approach to determine the astrophysical S factor of the reaction ⁷Be(p,γ). In previous experiments at RIKEN and GSI, the CD of ⁸B has been studied with different projectile energies [1,2]. In a new experiment at GSI we have measured this reaction at 254 A MeV using a secondary ⁸B beam from the FRS. The KaoS spectrometer was used to observe the breakup products in coincidence. The use of two PPACs positioned upstream from the target in combination with two pairs of silicon strip detectors directly after the target allows for angular distribution measurements of the excited ⁸B. This information is necessary to determine the strength of the E2-contribution in the breakup reaction which can influence the extracted astrophysical S₁₇ factor. Preliminary results are in good agreement with recent direct studies leading to a lower value of the astrophysical S₁₇ factor value.

[1] T. Kikuchi et al., Phys. Lett. B 391, 261 (1997).

[2] N. Iwasa et al., Phys. Rev. Lett. 83, 2910 (1999).