Determination of hexadecapole deformation for 160 Gd nucleus using quasi-elastic scattering

Nuclear structure plays an important role in heavy-ion fusion reactions at around Coulomb barrier energies by enhancing the fusion cross-section .When coupling of internal degrees of freedom take place with the relative motion of the reaction participants, a distribution of fusion barrier is observed instead of a single barrier [1]. Effects of channel coupling can be better visualised when the double derivative of the product of energy and fusion cross-section represents the fusion barrier distribution. Proper knowledge of quadrupole deformation parameter (β2) and hexadecapole deformation parameter (β4) can well account for the collective excitations due to rotation. Accurate values of β2 have been obtained using electromagnetic probes [2], but experimental determination of β4 is difficult with the results having large uncertainty and model-dependency. Various techniques like coulomb excitation, inelastic proton scattering have been used to obtain the value of β4. In recent time, attempts have been made to obtain β4 value using fusion. In the present experiment, we have obtained the value of β4 for 160 Gd using quasielastic (QEL) scattering at backward angles which is a process complementary to fusion.