Published March 2, 1999 | Version v1
Miscellaneous Open

The coulomb dissociation of 8B and implications for the S17 astrophysical S-Factor

Description

The interpretation of the solar neutrino flux observed on Earth compared to the predicted one depends on the cross section of the 7Be(p,γ)8B reaction (or equivalently on the Sn-factor) which has a rather large uncertainty (>20%) and has to be re-measured. The Coulomb dissociation of 8B is an alternative method to measure the S17-factor. We performed at GSI an experiment using a secondary radioactive beam of 8B at E(8B) = 254 A.MeV and the large acceptance spectrometer KaoS. Using an identification event by event and invariant-mass analysis, the differential Coulomb-dissociation cross section as a function the relative energy between fragments is deduced. Using the theorem of detailed balance, the S17-factor is extracted. With the help of theoretical descriptions, the measured data are extrapolated to solar energies. (author)

Abstract (French)

La comparaison entre le flux de neutrinos observes sur terre et les predictions theoriques depend de la section efficace de la reaction 7Be(p,γ)8B (ou du facteur astrophysique S17) qui a une large incertitude (>20%) et doit etre mesuree plus precisement. La dissociation coulombienne du B est une methode alternative pour mesurer le facteur S17. Nous avons realise a GSI une experience utilisant un faisceau secondaire radioactif de 8B a E(8B) = 254 A.MeV et le spectrometre a grande acceptance KaoS. En utilisant une identification evenement par evenement et une analyse de la masse invariante, la section efficace differentielle en fonction de l'energie relative entre les fragments est deduite. En utilisant le theoreme de 'detailed balance', le facteur Sn est extrait. A l'aide de descriptions theoriques, les donnees experimentales sont extrapolees aux energies du soleil. (auteur)

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Additional details

Additional titles

Original title (French)
La dissociation Coulombienne du

Publishing Information

Imprint Pagination
140 p.
Report number
FRCEA-TH--6261

Optional Information

Notes
99 refs.; Available from the INIS Liaison Officer for France, see the 'INIS contacts' section of the INIS website for current contact and E-mail addresses: http://www.iaea.org/inis/Contacts/
Secondary number(s)
CENBG--99-03