Few-nucleon transfer in quasi-elastic collisions at 20 MeV/nucleon.

Abstract

We report measurements of the isotopic distributions of targetlike fragments in coincidence with nitrogen, carbon, and boron isotopes from the reaction of 20 MeV/nucleon $^{14}\mathrm{N}$ with $^{165}\mathrm{Ho}$ and $^{164}\mathrm{Dy}$. The binary nature of the reaction was studied by observing particle-\ensuremath{\gamma}-ray coincidences; projectilelike fragments were identified near the classical grazing angle with a telescope consisting of silicon surface barrier detectors, and the targetlike fragments were identified by observing their discrete deexcitation \ensuremath{\gamma} rays in either of two high purity germanium detectors. The following reactions were studied: $^{164}\mathrm{Dy}$${(}^{14}$N,\ensuremath{\chi}xn), $^{164}\mathrm{Dy}$${(}^{14}$N,\ensuremath{\chi}\ensuremath{\alpha}xn), $^{165}\mathrm{N}$,Cxn), $^{165}\mathrm{Ho}$${(}^{14}$N,C\ensuremath{\alpha}xn), where \ensuremath{\chi}=nitrogen or boron isotopes. The inclusive energy spectra of the projectilelike fragments are reasonably described by either the extended Serber or the Friedman model of projectile breakup. Such interpretations of the reaction mechanism were further tested by comparing the targetlike fragment isotopic distributions to those expected from transfer of the unobserved breakup fragment to the target followed by statistical decay. The agreement of the predicted targetlike fragment isotopic distributions with the present data is remarkably good.