Fission ofU238andPu240Nuclei Excited by Inelastic Alpha-Particl

Fission probabilities ofAm242,Cm243, and

“…The comparison of experimental fission probabilities with statistical model calculations [9] provided also indirect but compelling evidence that the first fission barrier is axially asymmetric for most of the actinide region, as predicted by theoretical calculations of the potential energy surface [10]. In addition, measurements of fission probabilities combined with fission-fragment angular distributions yield information on the properties of the transition states at the two saddle points through which the nucleus may pass on its way to fission [11][12][13][14].…”

“…( *) ( *) ( *) ( *) In a recent work [19], where fission was induced via multinucleon transfer between 12 C and 238 U, a non negligible probability of exciting the carbon-like ejectiles was observed, that questioned the commonly used assumption that the excitation energy available in the transfer reaction is found only in the heavy reaction partner. 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.…”

Compound-nuclear reaction cross sections from surrogate measurements

“…In the following years, similar techniques were routinely used to study fission properties induced by direct reactions. Measurements were performed using ðd; pfÞ, ð; 0 fÞ, ðt; pfÞ, ðt; dfÞ, ð 3 He; dfÞ, and ð 3 He; tfÞ reactions to determine fission thresholds, the excitation-energy dependence of the fission probabilities, and/or the fission-fragment angular anisotropies for many different actinides (Wilkins, Unik, and Huizenga, 1964;Britt et al, 1965;Britt and Plasil, 1966;Specht, Fraser, and Milton, 1966;Britt, Rickey, and Hall, 1968;Wolf, Vandenbosch, and Loveland, 1968;Cramer, 1969, 1970;Cramer and Britt, 1970b;Back et al, 1974aBack et al, , 1974bGavron et al, 1975;Van Der Plicht et al, 1980;Wu et al, 1981;David et al, 1987;Sinha et al, 1992). These experiments used semiconductor detectors for both light-ion and fission-fragment detection.…”

“…Angular correlations between the outgoing direct-reaction particle and fission fragments were studied in the 1960s for ðd; pfÞ, ðt; pfÞ, ðt; dfÞ, and ð; 0 Þ reactions (Wilkins, Unik, and Huizenga, 1964;Britt et al, 1965;Britt and Plasil, 1966;Vandenbosch et al, 1967;Britt, Rickey, and Hall, 1968;Wolf, Vandenbosch, and Loveland, 1968;Britt and Cramer, 1969). For a given projectile-target combination, the fragment distributions were found to depend on a variety of parameters: (i) the energy E ex to which the nucleus B Ã was excited in the direct reaction; (ii) properties of the transition states populated in B Ã , such as the parity of the relevant state, as well as the angular momentum J and its projections K and M on the body-fixed and laboratory-fixed axes, respectively; and (iii) the angle of the outgoing direct-reaction particle with respect to the beam direction.…”

Determining (n,f) cross sections for actinide nuclei indirectly: Examination of the surrogate ratio method

“…Angular correlations between the outgoing directreaction particle and fission fragments were studied in the 1960s for (d,pf), (t,pf), (t,df), and (α, α f) reactions [37][38][39][40][41][42][43]. For a given projectile-target combination, the distributions W(θ, φ) were found to depend on a variety of parameters: i) the energy E * to which the nucleus B * was excited in the direct reaction; ii) properties of the transition states populated in B * , such as the parity π of the relevant state, as well as the angular-momentum J and its projections K and M on the body-fixed and laboratoryfixed axes, respectively; iii) the angle ψ of the outgoing direct-reaction particle with respect to the beam direction.…”