The ${}^9\text{Be(d}\text{, γ}{}_0\text{)}{}^{11}\text{B}$ reaction in the region of the giant dipole resonance

Abstract

The 90° yield of the ${}^9\text{Be(d}\text{, γ}{}_0\text{)}{}^{11}\text{B}$ reaction has been measured at deuteron energies ranging from 2.86 to 11.92 MeV in steps of 250 keV. Angular distributions have been obtained at E_d = 2.96, 6.87, 8.89 and 9.65 MeV. The γ-rays have been detected with a 23 cm × 23 cm NaI(Tl) crystal spectrometer enclosed in a plastic-scintillator anticoincidence shield. Evidence of structure has been observed in the excitation curve at E_d ≈ 3.4 and 9.65 MeV corresponding to excitation energies E_exc = 18.6 and 23.7 MeV, respectively. The angular distributions are typical of E1 transitions with a maximum at θ_L ≈ 90°. A calculation of the differential cross section of the inverse reaction, considered as a one-step direct process, gives results incompatible with the experiment and suggests that the ${}^9\text{Be(d}\text{,γ}{}_0\text{)}{}^{11}\text{B}$ reaction proceeds through excitation of the $\text{T =}\text{1}\text{2}$ component of the giant dipole resonance in ¹¹B.