Pb208(He3,He′3) Reaction at 43.7 MeV

Angular distributions for the (${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}\prime$) reaction exciting the first $2^{+}$, $3^{-}$, $4^{+}$, and $5^{-}$ levels of ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ have been measured from 13 to 50° using a bombarding energy of 43.67 MeV. The data were analyzed using both a collective model and a microscopic model. The microscopic calculations used the wave functions of Gillet, Green, and Sanderson. The distorted-wave Born-approximation calculations do not provide good fits at very forward angles; this problem appears to become more severe with increasing multipolarity. As Park and Satchler have recently pointed out, the interference between the Coulomb and nuclear parts of the form factor allows one to measure the phase of the effective microscopic interaction. The results of the present experiment indicate that this phase is near $\frac{\pi }{3}$ for the ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$(${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}\prime$) reaction.