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The elastic scattering of 6He on 208Pb has been measured at laboratory energies of 14, 16, 18 and 22 MeV. These data were analyzed using phenomenological Woods- Saxon form factors and optical model calculations. A semiclassical polarization po- tential was used to study the e ect of the Coulomb dipole polarizability. Evidence for long range absorption, partially arising from Coulomb dipole polarizability, is reported. The energy variation of the optical potential was found to be consistent with the dispersion relations which connect the real and imaginary parts of the potential

New experimental data from the scattering of 6 He + 208 Pb at energies around and below the Coulomb barrier are presented. The yield of breakup products coming from projectile fragmentation is dominated by a strong group of α particles. The energy and angular distribution of this group have been analyzed and compared with theoretical calculations. This analysis indicates that the α particles emitted at backward angles in this reaction are mainly due to two-neutron transfer to weakly bound states of the final nucleus.

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Experimental results of the elastic scattering of 6 He on 208 Pb at E LAB = 22 MeV, measured at the CRC facility (Louvain-la-Neuve, Belgium), are presented, including results on the 4 He production channel. These data were taken with full angular coverage and high angular resolution. Both experimental cross sections are compared with continuum discretized coupled channels and distorted-wave Born approximation calculations, where direct breakup and transfer to the continuum processes are considered. The elastic data confirm the absence of the Coulomb rainbow, while the distribution of α particles indicates that such production is mostly generated by transfer to the continuum.

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We have extended the experiment reported in Bradfield-Smith et al. ͓Phys. Rev. C 59, 3402 ͑1999͔͒ concerning the 18 Ne(␣,p) 21 Na reaction, which is of importance to nuclear astrophysics. This study covered an energy region ϳ1.7-2.9 MeV in the center of mass frame of the 18 Neϩ␣ system. A change in the detector geometry resulted in an increase in the detection efficiency and significantly reduced the proton background that hindered the previous measurement. A direct measurement of the energy loss of the 18 Ne beam, as it passed through He gas, was undertaken to reduce a major source of uncertainty in the determination of the stellar reaction rate. Eight states have been identified in the compound nucleus, 22 Mg. These resonances were used to calculate an enhanced stellar reaction rate which shows good agreement with theoretical predictions ͓Görres, Wiescher, and Thielemann, Phys. Rev. C 51, 392 ͑1995͔͒ at and above a temperature of 1.5 GK. The impact of this enhanced stellar reaction rate upon the nucleosynthesis that occurs during the peak phase of an x-ray burst has been investigated.

Quasi-elastic scattering of 6 He at E lab =27 MeV from 197 Au has been measured in the angular range of 6• − 72• in the laboratory system employing LEDA and LAMP detection systems. These data, along previously analysed data of 6 He + 208 Pb at the same energy, are analysed using Optical Model calculations. The role of Coulomb dipole polarizability has been investigated. Large imaginary diffuseness parameters are required to fit the data. This result is an evidence for long range absorption mechanisms in 6 He induced reactions.