Transition state rates and mass asymmetric fission barriers of compound nuclei 90,94,98Mo

Jing, K.; Moretto, L. G.; Veeck, A.; Colonna, N.; Lhenry, I.; Tso, K.; Hanold, K.; Skulski, W.; Sui, Qingli; Wozniak, G. J.

doi:10.1016/s0375-9474(98)00606-x

Cited by 43 publications

(49 citation statements)

References 63 publications

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“…While it has been quite well established that dissipation is rather strong in the large-distortion range [9,10,11,2], the situation is still unclear in the small-deformation regime [12,13,14,15,16]. One of the reasons for the vivid debates concerning the strength of nuclear dissipation is the large amount of complex side effects entering into the description of the fission mechanism, in particular in fusion-fission experiments, which often induce large angular momenta and deformations.…”

Section: Experimental Approachmentioning

confidence: 99%

Conditions for the manifestation of transient effects in fission

et al. 2005

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Abstract:We examine the manifestation of transient effects in fission by analysing experimental data where fission is induced by peripheral heavy-ion collisions at relativistic energies. Available total nuclear fission cross sections of 238 U at 1⋅A GeV on gold and uranium targets are compared with a nuclear-reaction code, where transient effects in fission are modelled using different approximations to the numerical time-dependent fission-decay width: a new analytical description based on the solution of the Fokker-Planck equation and two widely used but less realistic descriptions, a step function and an exponential-like function. The experimental data are only reproduced when transient effects are considered. The deduced value of the dissipation strength β depends strongly on the approximation applied for the time-dependent fission-decay width and is estimated to be of the order of 2·10 21 s -1. A careful analysis sheds severe doubts on the use of the exponential-like in-growth function largely used in the past. Finally, we discuss which should be the characteristics of experimental observables to be most sensitive to transient effects in fission.

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Section: Experimental Approachmentioning

confidence: 99%

Conditions for the manifestation of transient effects in fission

et al. 2005

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“…The rotating finite-range model [17] or the rotating liquid-drop model is used to calculate the conditional barriers for binary division. As found, the mass asymmetric fission barriers extracted from the experimental excitation functions lie between the values calculated with these two models [18,19]. Applications of the statistical model [14,15] are restricted to compound nucleus formation, and for a good description of the mass distribution with this model, the maximum angular momentum J max of the system is specially adjusted.…”

Section: Introductionmentioning

confidence: 52%

Role of angular momentum in the production of complex fragments in fusion and quasifission reactions

et al. 2011

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The influence of angular momentum on the competition between complete fusion followed by the decay of compound nucleus and quasifission channels is treated within the dinuclear system model. The charge distributions of the products in the reactions 28 Si+ 96 Zr, 4 He+ 130 Te, and 40 Ca+ 82 Kr are predicted at bombarding energies above the Coulomb barrier. The results of calculations for the reactions 93 Nb+

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“…σ Z for frag-02001-p.4 ments with Z≤10 presents a strong even-odd staggering (e-o-s), and this effect is still seen for higher Z with a smaller amplitude. Staggering of the fragments cross-sections have already been observed in a wide range of energy [14][15][16][17][18] from compound nucleus reactions to spallation and multifragmentation regimes. Moreover, it is worth noting that the Z-distribution obtained in the present work is very close to those measured in nuclear systems prepared in roughly the same conditions in terms of excitation energy and angular momentum [19][20][21] This common features in the yields of the light clusters would indicate that the even-odd staggering observed in the present work is more likely related to the intrinsic properties of light clusters since the heavy complementary partner is different in each system.…”

Section: Resultsmentioning

confidence: 99%

Asymmetric Fission in the⁷⁸Kr+⁴⁰Ca reactions at 5.5 MeV/nucleon

Bec

Wieleczko

Adémard

et al. 2012

EPJ Web of Conferences

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Abstract.The cross section, kinetic energy distribution and angular distribution of fragments with atomic number 3 ≤ Z ≤ 28 emitted in the reaction 78 Kr + 40 Ca at the bombarding energy of 5.5 MeV/nucleon and coincidence between light charged particles and fragments were measured by means of the 4π-INDRA array to study the decay mechanism of medium mass excited nucleus. Global features indicate a high degree of relaxation and are compatible with a binary fission from compound nucleus. The mean value of the kinetic energy distributions of fragments indicates dominance of Coulomb interaction, while the width of the distribution signals large fluctuations. Inclusive cross-section distributions of fragments with charge 3 ≤ Z ≤ 28 are bell-shaped and a strong even-odd-staggering (o-es) is observed for 3 ≤ Z ≤ 12. Coincidence measurements suggest that the light partners in very asymmetric fission are emitted at excitation energies below the particle emission thresholds. Data were confronted to the predictions of statistical model describing the decay of compound nuclei by emission of light particles and fragments. Calculations assuming spherical fission fragments and finite-range liquid drop fission barriers are not able to explain the experimental features. Attempts have been made to improve the agreement with experimental data. The analysis indicates the strong influence of the shape parameterization of the potential energy surface in describing the fission process of intermediate mass compound nuclei. a

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Transition state rates and mass asymmetric fission barriers of compound nuclei 90,94,98Mo

Cited by 43 publications

References 63 publications

Conditions for the manifestation of transient effects in fission

Conditions for the manifestation of transient effects in fission

Role of angular momentum in the production of complex fragments in fusion and quasifission reactions

Asymmetric Fission in the⁷⁸Kr+⁴⁰Ca reactions at 5.5 MeV/nucleon

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Transition state rates and mass asymmetric fission barriers of compound nuclei 90,94,98Mo

Cited by 43 publications

References 63 publications

Conditions for the manifestation of transient effects in fission

Conditions for the manifestation of transient effects in fission

Role of angular momentum in the production of complex fragments in fusion and quasifission reactions

Asymmetric Fission in the78Kr+40Ca reactions at 5.5 MeV/nucleon

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Product

Resources

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Asymmetric Fission in the⁷⁸Kr+⁴⁰Ca reactions at 5.5 MeV/nucleon