Nuclear-matter distributions of halo nuclei from elastic proton scattering in inverse kinematicsP. Egelhof1, G.D. Alkhazov2, M.N. Andronenko2, A. Bauchet1, A.V. Dobrovolsky1, 2, S. Fritz1, G.E. Gavrilov2, H. Geissel1, C. Gross1, A.V. Khanzadeev2, G.A. Korolev2, G. Kraus1, A.A. Lobodenko2, G. Münzenberg1, M. Mutterer3, S.R. Neumaier1, T. Schäfer1, C. Scheidenberger1, D.M. Seliverstov2, N.A. Timofeev2, A.A. Vorobyov2 and V.I. Yatsoura2
1 Gesellschaft für Schwerionenforschung (GSI), D-64291 Darmstadt, Germany
2 Petersburg Nuclear Physics Institute (PNPI), RU-188300 Gatchina, Russia
3 Institut für Kernphysik (IKP), Technische Universität, D-64289 Darmstadt, Germany
(Received: 21 March 2002 / Published online: 31 October 2002)
Proton-nucleus elastic scattering at intermediate energies, a well-established method for probing nuclear-matter density distributions of stable nuclei, was applied for the first time to exotic nuclei. This method is demonstrated to be an effective means for obtaining accurate and detailed information on the size and radial shape of halo nuclei. Absolute differential cross-sections for small-angle scattering were measured at energies near 700 MeV/u for the neutron-rich helium isotopes and , and more recently for the lithium isotopes , , and , using He and Li beams provided by the fragment separator FRS at GSI Darmstadt. Experiments were performed in inverse kinematics using the hydrogen-filled ionization chamber IKAR which served simultaneously as target and recoil-proton detector. For deducing nuclear-matter distributions, differential cross-sections calculated with the aid of the Glauber multiple-scattering theory, using various parametrizations for the nucleon density distributions as input, were fitted to the experimental cross-sections. The results on nuclear-matter radii and matter distributions are presented, and the significance of the data for a halo structure is discussed. Nuclear-matter distributions obtained for and conform with the concept that both nuclei compose of -particle like cores and significant neutron halos. The matter distribution in exhibits, as expected from previous reaction cross-section studies with nuclear targets, the by far most extended halo component of all nuclei being investigated. In addition the present data allow a quantitative comparison of the structure of the He and Li isobares of either the mass number A=6 or A=8. The measured differential cross-sections have also been used for probing density distributions as predicted from various microscopic calculations. A few examples are presented.
21.10.Gv - Mass and neutron distributions.
25.40.Cm - Elastic proton scattering.
27.20.+n - .
© Società Italiana di Fisica, Springer-Verlag 2002