The study of the (α, α'f) reaction at 120 MeV on 232Th and 238U

Fission probabilities ofAm242,Cm243, and

“…In this work, we deal with 3 He-induced transfer reactions where the ejectile can be a deuteron, a triton or an α particle, and the maximum total available excitation energy is essentially below 20 MeV. Deuterons and tritons have no bound excited states and will break up if excited, while the first excited state of 4 He is located at 20.2 MeV. Therefore, all the detected ejectiles are in their ground state and all the excitation energy available in the reaction can safely be attributed to the fissioning nucleus A.…”

“…Transfer reactions with light projectiles have often been used in the past to induce fission, see e.g. [1][2][3][4][5][6]. The fission probabilities obtained in these measurements were frequently used to investigate the fission thresholds below the neutron separation energy (S n ) of even-even fissioning nuclei, which are not accessible in neutron-induced reactions, e.g.…”

“…4. The broad peaks at the highest excitation energies in the 4 He spectrum stem from transfer reactions on the 13 C present in the carbon backing and on 16 O, 19 F and 35,37 Cl impurities in the target. The background from reactions on the carbon support was measured separately with a carbon target with the same characteristics as the target backing.…”

“…By selecting one type (Z, A) of ejectile, for example 4 He, the so-called "singles" spectrum N sing (E*), can be obtained. In this particular case, it represents the number of detected 242 Am nuclei as a function of their excitation energy.…”

“…In this particular case, it represents the number of detected 242 Am nuclei as a function of their excitation energy. The singles spectrum is derived from the spectrum of 4 He as a function of the excitation energy of 242 Am represented by the triangles on Fig. 4.…”