http://rabida.uhu.es/dspace/bitstream/handle/10272/5530/Study_of_the_elastic_scattering.pdf?sequence=2

Study of the elastic scattering of 6He on 208Pb at energies around the Coulomb barrier

The structure of the three-body Borromean nucleus {sup 6}He is approximated by a two-body di-neutron cluster model. The binding energy of the 2n-{alpha} system is determined to obtain a correct description of the 2n-{alpha} coordinate, as given by a realistic three-body model calculation. The model is applied to describe the breakup effects in elastic scattering of {sup 6}He on several targets, for which experimental data exist. We show that an adequate description of the di-neutron-core degree of freedom permits a fairly accurate description of the elastic scattering of {sup 6}He on different targets.

/pdf/improved-di-neutron-cluster-model-for-he-6-scattering-17r3t70e6g.pdf

Improved di-neutron cluster model for He-6 scattering

Excitation functions for total reaction cross sections, ${\ensuremath{\sigma}}_{R}$, were measured for the light, mainly proton-rich nuclei $^{6}\mathrm{Li}$, $^{7}\mathrm{Be}$, $^{10}\mathrm{B}$, $^{9,10,11}\mathrm{C}$, $^{12}\mathrm{N}$, $^{13,15}\mathrm{O}$, and $^{17}\mathrm{Ne}$ incident on a Si telescope at energies between 15 and 53 MeV/nucleon. The telescope served as target, energy degrader and detector. Proton-removal cross sections, ${\ensuremath{\sigma}}_{2p}$ for $^{17}\mathrm{Ne}$ and ${\ensuremath{\sigma}}_{p}$ for most of the other projectiles, were also measured. The strong absorption model reproduces the $A$-dependence of ${\ensuremath{\sigma}}_{R}$, but not the detailed structure. Glauber multiple scattering theory and the Jeukenne, Lejeune, and Mahaux (JLM) folding model provided improved descriptions of the measured ${\ensuremath{\sigma}}_{R}$ values. Rms radii, extracted from the measured ${\ensuremath{\sigma}}_{R}$ using the optical limit of Glauber theory, are in good agreement with those obtained from high energy data. One-proton removal reactions are described using an extended Glauber model, incorporating second order noneikonal corrections, realistic single particle densities, and spectroscopic factors from shell model calculations.

Reaction and proton-removal cross sections of Li6, Be7, B10, C9,10,11, N12, O13,15, and Ne17 on Si at 15 to 53 MeV/nucleon

The $\ensuremath{\alpha}+2n$ and $t+t$ clustering of the $^{6}\mathrm{He}$ ground state were investigated by means of the transfer reaction $^{6}\mathrm{He}(p,t)^{4}\mathrm{He}$ at 25 MeV/nucleon. The experiment was performed in inverse kinematics at GANIL with the SPEG spectrometer coupled to the MUST array. Experimental data for the transfer reaction were analyzed by a distorted wave Born approximation (DWBA) calculation, including the two neutrons and the triton transfer. The couplings to the $^{6}\mathrm{He}\ensuremath{\rightarrow}^{4}\mathrm{He}+2n$ breakup channels were taken into account with a polarization potential deduced from a coupled-discretized-continuum channels analysis of the $^{6}\mathrm{He}+^{1}\mathrm{H}$ elastic scattering measured at the same time. The influence on the calculations of the $\ensuremath{\alpha}+t$ exit potential and of the triton sequential transfer is discussed. The final calculation gives a spectroscopic factor close to one for the $\ensuremath{\alpha}+2n$ configuration as expected. The spectroscopic factor obtained for the $t+t$ configuration is much smaller than the theoretical predictions.

Investigation of 6He cluster structures

Virtual coupling potential for elastic scattering of 10,11Be on proton and carbon targets

We study the local dynamic polarization potential (DPP) component of the ${}^{6}\mathrm{He}+p$ interaction, determining that part which is due to breakup processes. Results are presented for c.m. energies of 21.57 and 35.06 MeV. The DPP is found by subjecting the elastic scattering S matrix from continuum-discretized coupled-channels calculations to S matri$\stackrel{\ensuremath{\rightarrow}}{\mathrm{x}}$potential inversion. The iterative-perturbative inversion method is employed, and the method is shown to give reliable potentials down to projectile-target separation close to zero, a necessary requirement for this case. The contributions of different continuum states are compared, and the way they interact to give the overall DPP is studied. The DPP is found to be very different from that determined using the weighted trivially equivalent approximate method.

K. Rusek

Papers

Dynamic polarization potential for 6 He+p due to breakup