6 pages, 5 figures.-- El pdf del artículo es la versión pre-print.-- et al.We have measured elastic cross sections of the scattering of 6 He at E-Lab 14, 16, 17, 18 and 22 MeV on Pb-208 in the angular ranges of 20 degrees-64 degrees and 135 degrees-170 degrees. A significant amount of He-4 events is found at energies well below the Coulomb barrier, that becomes dominant above it. Optical model calculations have been performed including a dynamic polarization potential. Very large imaginary diffuseness parameter is needed in order to describe the experimental distributions.This work has been partially supported by the Spanish Dirección General de Investigación, Ciencia y Tecnología under project numbers FPA2000-1592-C03-02, FPA2002-04181-C04-02/04, the Belgian program P5/07 on interuniversity attraction poles of the Belgian-state Federal Services for Scientific, Technical and Cultural Affairs, and the European Community-Access to Research Infrastructure action of the Improving Human Potential Programme, contract no HPRI-CT-1999-00110. AMSB acknowledges a research grant from the Spanish MCyT.This work has been partially supported by the Spanish Dirección General de Investigación, Ciencia y Tecnología under projects number FPA2000-1592-C03-02, FPA2002-04181-C04-02/04, the Belgian program P5/07 on interuniversity attraction poles of the Belgian-state Federal Services for Scientific, Technical and Cultural Affairs, and the European Community-Access to Research Infrastructure action of the Improving Human Potential Programme, contract Nº HPRI-CT-1999-00110. A.M.S.B. acknowledges a research grant from the Spanish MCyT.Peer reviewed