RADIATIVE CAPTURE OF HEAVY IONS

The process of radiative capture of heavy ions was successfully observed for the first time by means of the high-energy γ-radiation produced in the reactions 7Li(16O, γ)23Na, 11B(12C, γ)23Na, 6Li(16O, γ)22Na, 12C(12C, γ)24Mg, 12C(16O, γ)28Si and 16O(16O, γ) 32S. The 7Li(16O, γ)23Na reaction was studied at θ = 90° for Ex = 23-29 MeV. A resonance-like structure was observed peaking at Ex = 25.4 MeV with a c.m. width of 0.67±0.20 MeV (dσ/dΩpeak = 192±58 nb/sr). An angular distribution of the peak cross section can be fitted by 1-(0.21±0.03)P1 or 1-(0.15±0.10)P2. Possible explanations of this behavior are discussed. The 11B(12C, γ)23Na reaction was studied at θ = 90° for Ex = 23 - 27 MeV. Only weak structure was observed. For the remaining reactions, uniformly low yields were observed with typical maximum cross sections of the order of dσ/dΩ = 30 nb/sr for bombarding energies close to the respective Coulomb barriers. Particle spectra were measured for 7Li+16O reactions emitting p, d, t or α-particles corresponding to Ex = 24.6-27.2 MeV. Weak structure found in the various excitation curves is suggestive of compound nucleus formation in the reaction. © 1969.