Neutron decay widths of excited states ofBe11

Abstract

The two-neutron transfer reaction $^{9}\mathrm{Be}$($^{16}\mathrm{O}$, $^{14}\mathrm{O}$)$^{11}\mathrm{Be}$[$^{10}\mathrm{Be}$ $+n$] has been used to measure the branching ratios for the neutron decay of excited states of $^{11}\mathrm{Be}$. The $^{14}\mathrm{O}$ ejectile was detected by a Q3D spectrometer at forward angles. The energies and angles of the $^{10}\mathrm{Be}$ fragments of the decaying $^{11}\mathrm{Be}$${}^{*}$ recoil were measured in coincidence with the $^{14}\mathrm{O}$ ejectile using a double-sided silicon strip detector array at backward angles. This enabled a kinematic reconstruction of the reaction to be performed. Theoretical decay branch ratios were calculated using barrier penetrability factors and were compared to the measured ratios to provide information on the relative reduced widths of the states. The decay widths have been used to link states in $^{11}\mathrm{Be}$ with a common structure and structurally to states in the daughter nucleus $^{10}\mathrm{Be}$. The $3/{2}^{\ensuremath{-}} 8.82$-MeV state was identified as a candidate for a molecular band head.