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Charged particles emitted in ternary fission appear to have a Gaussian-shaped energy distribution, except for the α particles, for which mostly an important non-Gaussian low-energy tailing is reported. We realised good experimental conditions for studying the 235U(nth, f) ternary α energy distribution at the reactor of the ILL in Grenoble. Thanks to an intense and clean neutron beam, a small, thin sample of highly enriched U could be used, with an activity of only 1.6 Bq, so the measurements could be done without absorber in between the sample and the detector. With the resulting low detection limit of 6 MeV, a clearly asymmetric energy distribution was obtained, deviating by 6% from a Gaussian shape. This energy distribution has been deconvoluted into components corresponding to “true” ternary α''s and α''s originating from the decay of 5He particles. Ternary α emission yield data have been re-evaluated accordingly. [Copyright &y& Elsevier]

Abstract: The emission probabilities and the energy distributions of tritons, α and 6He particles emitted in the spontaneous ternary fission (zero excitation energy) of 250Cf and 252Cf and in the cold neutron induced fission (excitation energy ) of 249Cf and 251Cf are determined. The particle identification was done with suited telescope detectors, at the IRMM (Geel, Belgium) for the spontaneous fission and at the ILL (Grenoble, France) for the neutron induced fission measurements. Hence particle emission characteristics of the fissioning systems 250Cf and 252Cf are obtained at zero and at about 6.5 MeV excitation energies. While the triton emission probability is hardly influenced by the excitation energy, the 4He and 6He emission probability in spontaneous fission is higher than for neutron induced fission. This can be explained by the strong influence of the cluster preformation probability on the ternary particle emission probability. [Copyright &y& Elsevier]

The emission probabilities and the energy distributions of tritons and α particles emitted in the spontaneous ternary fission (zero excitation energy) of 244Cm, 246Cm and 248Cm and in the cold neutron induced fission (excitation energy ≈ 605MeV) of 243Cm, 245Cm and 247Cm are determined. The particle identification was done with suited ΔE -E telescope detectors, at the IRMM (Geel, Belgium) for the spontaneous fission and at the ILL (Grenoble, France) for the neutron induced fission measurements. Hence particle emission characteristics of the fissioning systems 244Cm, 246Cm and 248Cm are obtained at zero excitation energy and at an excitation energy around 6.5 MeV. Whilst the triton emission probability is hardly influenced by the excitation energy, the 4He emission probability in spontaneous fission is about 20% higher than for neutron induced fission. This could be explained by the influence of the cluster preformation probability on the ternary α emission. [Copyright &y& Elsevier]

This paper reports on the results of measurements of the (n,p) and (n,α) reactions on 26Al and 36Cl, in the neutron energy region up to 140 keV and 350 keV, respectively. The experiments were carried out at the GELINA neutron facility of the IRMM (Geel, Belgium). For both reactions several resonances could be identified which were never observed before. Using the obtained cross section data, reaction rates were calculated and compared with other experimental and theoretical values. [Copyright &y& Elsevier]