Employing the quantal diffusion mechanism for multi-nucleon transfer, the double differential cross-sections are calculated for production of primary projectile-like and target-like fragments in collisions of ${}^{136}text{Xe}+{}^{208}text{Pb}$ system at $E_text{c.m.} =514$ MeV. Including de-excitation due to neutron emission, the cross-section for production of ${}^{210}text{Po}$, ${}^{222}text{Rn}$ and ${}^{224}text{Ra}$ isotopes are estimated and compared with data.