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International Symposium on Nuclear Astrophysics -- Nuclei in the Cosmos -- IX, Genève : Suisse (2005)
Direct measurement of the 18F(p,alpha)15O reaction for application to nova gamma-ray emission
N. De Séréville1, C. Angulo1, P. Leleux1, A. Coc2, J. Kiener2, A. Lefebvre2, V. Tatischeff2, P. Descouvemont, P. Figuera, F. Hammache3, N.L. Achouri4, N.A. Orr4, L. Stefan5, E. Casajeros, T. Davinson, D. Robertson, A. Laird, S. Fox, P. Mumby-Croft, K. Vaughan

The 18F nucleus is one of the radioactive isotopes produced during nova explosions. It is of particular interest since it is mainly responsible for the 511 keV gamma-ray emission of novae that could be detected with the INTEGRAL satellite or future gamma-ray telescopes. The amount of 18F synthesised still suffers from large uncertainties coming from missing nuclear information concerning the 18F destruction reaction 18F(p,a)15O. In particular, the interference sign between three 3/2+ resonances in 19Ne, situated slightly above the proton threshold (8 keV and/or 38 keV) and at higher energy (665 keV), is unknown. The maximum effect of these interferences is lying in the energy range corresponding to the Gamow peak region and has a strong impact on the 18F(p,a)15O reaction rate. We report here on the direct measurement at low energy (down to 400 keV in the center-of-mass) of the 18F(p,a)15O total cross section that we performed at the Louvain-la-Neuve CRC-RIB facility with the high-intensity and -purity 18F radioactive beam (T1/2 = 110 min). The total cross section for the different incident energies will be presented and compared to previous experimental data.
1 :  UCL - Université Catholique de Louvain
2 :  CSNSM - Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse
3 :  IPNO - Institut de Physique Nucléaire d'Orsay
4 :  LPCC - Laboratoire de Physique Corpusculaire de Caen
5 :  GANIL - Grand Accélérateur National d'Ions Lourds
structure nucléaire
Physique/Physique Nucléaire Expérimentale