Proton-hole states in 115In observed in the 116Sn(d, 3He) reaction

The ¹¹⁶Sn(d, ³He)¹¹⁵In reaction has been investigated at E_d = 50 MeV. Thirteen transitions to states up to 3 MeV excitation energy were studied. The measured angular distributions were compared with DWBA calculations and transferred angular momenta and spectroscopic factors were deduced. Levels at 1.04, 2.23 and 2.52 MeV were found to be excited most likely by l = 3 angular momentum transfer in contrast to previous investigations at lower incident energies in which no l = 3 transitions have been observed.     

First excited 0+ states in the germanium isotopes via the Se(d, 6Li) reaction

A systematic study of the even-A germanium isotopes with mass 70 ≦ A ≦ 78 via the Se(d, ⁶Li) reaction has been performed at E_d = 45 MeV. The reaction products were momentum analysed and mass identified with a QMG/2 magnetic spectrograph and the accompanying focal-plane detector system. The main emphasis of this investigation was on the nature of the first excited 0⁺ states. The striking variation in strength from one isotope to the other already observed in the (p, t) reactions to the same final nuclei is also seen for the α-pickup reaction. Previously derived wave functions that assume the excited 0⁺₂ states to be pure proton configuration states can also account for the present results.     

Incomplete fusion in 12C+160Gd collisions

The mechanism of the production of fast α-particles in ¹²C induced reactions was studied over a wide range of bombarding energies (7.5–16.7 MeV/A) by measuring α-γ coincidences. Absolute cross sections for ${}^{160}\text{Gd}\text{(}{}^{12}\text{C}\text{, αx}\text{n}\text{)}{}^{\mathrm{168?x}}\text{Er and}{}^{160}\text{Gd}\text{(}{}^{12}\text{C}\text{, 2αx}\text{n}\text{)}{}^{\mathrm{164?x}}\text{Dy}$ reactions, as well as inclusive α-particle production cross sections, have been determined. Depending on the bombarding energy, a fraction of 0.2–0.4 of the singles α-particles can be explained as resulting from incomplete fusion reactions (¹²C, α) and (¹²C, 2α) which correspond to a capture of “⁸Be” and “⁴He”, respectively. The remaining fragments of the projectile have, on the average, the beam-velocity energies and their angular distributions are forward peaked. Distributions of side-feeding to the yrast bands in the target-residue nuclei indicate that low partial waves are strongly hindered in the incomplete fusion reactions. The energy dependence of the cross sections for (¹²C, α) and (¹²C, 2α) incomplete fusion as well as for (¹²C, 3α) projectile breakup is given. A generalized concept of critical angular momentum which explains a competition between complete fusion, incomplete fusion and breakup reactions is proposed.     

Observation of the hot GDR in neutron-deficient thorium evaporation residues

The giant dipole resonance built on excited states was observed in very fissile nuclei in coincidence with evaporation residues. The reaction ⁴⁸Ca + ¹⁷⁶Yb populated evaporation residues of mass A=213–220 with a cross section of 200 μb at 259 MeV. The extracted giant dipole resonance parameters are in agreement with theoretical predictions for this mass region.     

Generation and division of excitation energy in heavy-ion collisions studied by measuring charged-particle survival fractions

Charged-particle survival fractions of primary projectile-like fragments from the ⁴⁰Ar + ¹⁹⁷Au reaction at 450 MeV were measured by using a large array of 32 phoswich detectors operating in coincidence with a detector of projectile-like fragments. Differential survival fractions of the primary pickup and stripping reaction products indicate a dependence of the average excitation energy generated in the primary fragments on the direction of the mass transfer.