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Gomez-Camacho, J

Publications and source records attributed to Gomez-Camacho, J.

Core excitation effects in the breakup of halo nuclei

The role of core excitation in the structure and dynamics of two-body halo nuclei is investigated. We present calculations for the resonant breakup of {sup 11}Be on protons at an incident energy of 63.7 MeV/nucleon, where core excitation effects were shown to be important. To describe the reaction, we use a recently developed extension of the DWBA formalism which incorporates these core excitation effects within the no-recoil approximation. The validity of the no-recoil approximation is also examined by comparing with DWBA calculations which take into account core recoil. In addition, calculations with two different continuum representations are presented and compared.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Elastic scattering of {sup 9}Li on {sup 208}Pb at energies around the Coulomb barrier

We have studied the dynamical effects of the halo structure of {sup 11}Li on the scattering on heavy targets at energies around the Coulomb barrier. This experiment was performed at ISAC-II at TRIUMF with a world record in production of the post-accelerated {sup 11}Li beam. As part of this study we report here on the first measurement of the elastic cross section of the core nucleus, i.e. {sup 9}Li on {sup 208}Pb, at energies around the Coulomb barrier. A preliminary optical model analysis has been performed in order to extract a global optical potential to describe the measured angular distributions.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Spectroscopy of proton-unbound nuclei by tracking their decay products in-flight: One- and two- proton decays of {sup 15}F, {sup 16}Ne, and {sup 19}Na

A powerful method of investigating proton-unbound nuclear states by tracking their decay products in flight is discussed in detail. To verify the method, four known levels in {sup 15}F, {sup 16}Ne, and {sup 19}Na were investigated by measuring the angular correlations between protons and the respective heavy-ion fragments stemming from the precursor decays in flight. The parent nuclei of interest were produced in nuclear reactions of one-neutron removal from {sup 17}Ne and {sup 20}Mg projectiles at energies of 410-450 A MeV. The trajectories of the respective decay products, {sup 14}O + p + p and {sup 18}Ne + p + p, were measured by applying a tracking technique with microstrip detectors. These data were used to reconstruct the angular correlations of the fragments, which provided information on energies and widths of the parent states. In addition for reproducing properties of known states, evidence for hitherto unknown excited states in {sup 15}F and {sup 16}Ne was found. This tracking technique has an advantage in studies of exotic nuclei beyond the proton drip line measuring the resonance energies and widths with a high precision although by using low-intensity beams and very thick targets.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Exploring continuum structures with a pseudo-state basis

The ability of a recently developed square-integrable discrete basis to represent the properties of the continuum of a two-body system is investigated. The basis is obtained performing a simple analytic local scale transformation to the harmonic oscillator basis. Scattering phase-shifts and the electric transition probabilities B(E1) and B(E2) have been evaluated for several potentials using the proposed basis. Both quantities are found to be in excellent agreement with the exact values calculated from the true scattering states. The basis has been applied to describe the projectile continuum in the {sup 6}He scattering by {sup 12}C and {sup 208}Pb targets at 240 MeV/nucleon and the {sup 11}Be scattering by {sup 12}C at 67 MeV/nucleon. The calculated breakup differential cross sections are found to be in very good agreement with the available experimental data for these reactions.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗