N17Energy Levels and Gamma Rays

Abstract

The nuclear reaction ${\mathrm{Li}}^{7}$+${\mathrm{B}}^{11}$ was studied with the use of a three-parameter analysis technique. The three parameters recorded were particle type, particle energy, and energy of gamma rays in time coincidence with the charged particles. Both ungated particle spectra and particle-gamma-ray coincidence data were taken simultaneously. Particles were detected by a $E\ensuremath{-}\frac{\mathrm{dE}}{\mathrm{dX}}$ system made up of solid-state detectors. The gamma rays were detected in a large NaI (Tl) crystal. The data gathering and analyzing system consisted of three pulse-height analyzers (256 channels for ${E}_{\ensuremath{\gamma}}$ and $\ensuremath{\Delta}E$, and 1024 channels for ${E}_{\mathrm{particle}}$), and a small general-purpose computer with magnetic tape units and an oscilliscope display. The energies of protons from the reaction ${\mathrm{B}}^{11}({\mathrm{Li}}^{7}, p){\mathrm{N}}^{17}$ were measured. Groups corresponding to previously observed states in ${\mathrm{N}}^{17}$ were seen as well as 14 new states. Spectra of gamma rays from the bound levels of ${\mathrm{N}}^{17}$ were analyzed to give the decay schemes and some branching ratios. Calibrations were obtained from gamma rays of known energy produced in the reaction and from the known energies of some of the proton, deuteron, and triton groups.