Tiny investigations of the splitting procedure

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Minute investigations of the parting process. Individuals included: J.- F. Berger, J.- P. Delaroche CEA Bruy

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Slide 1

Tiny investigations of the parting procedure People included: J.- F. Berger, J.- P. Delaroche CEA Bruyères-le-Châtel N. Dubray (soon in the ESNT) H. Goutte D. Gogny Livermore, USA Dobrowolski Lublin, Poland - futur advancement - D. Lacroix GANIL C. Simenel Saclay

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Many utilizations of the splitting procedure Energy creation Ex: Thorium cycle, ADS Production of fascinating cores Ex: SPIRAL 2 Role of parting in astronomy Fission is utilized or potentially considered in new spaces where no exp. information exist (new nuclei,for a huge scope of episode vitality).  Accurate expectations are required

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Fission: numerous principal questions !! Atomic properties brought into play: * atomic designs a long way from balance * huge adequacy aggregate vibrations * coupling between aggregate degrees of opportunity * couplings amongst group and characteristic degrees of flexibility Many open inquiries: * Shell impacts everywhere prolongation * Influence of the elements : (ex: coupling between aggregate modes and inherent excitations) * Effects of the temperature (excitation vitality) * Description of the underlying condition of the fissioning framework * Fission of odd cores * Number of splitting modes (number of aggregate directions required) * Very deviated parting * …

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Microscopic treatment with no blending relationships : Time-Dependent Hartree-Fock Microscopic treatment utilizing adiabatic theory : Time-Dependent GCM + GOA Fission: diverse methodologies – Dynamical portrayal Non treated yet impacts are reenacted utilizing measurable speculation Statistical harmony at the scission point (Fong's model ) Random breaking of the neck (Brosa's model ) Scission point demonstrate (Wilkins-Steinberg ) Saddle point display (ABBLA) Treated utilizing a (semi-) traditional approach : Transport conditions Classical directions + thickness Classical directions + Langevin term

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What we have done: Our theory • splitting elements is represented by the advancement of two aggregate parameters q i (extension and asymmetry) • Internal structure is at balance at each progression of the aggregate development • Adiabaticity • no vanishing of pre-scission neutrons  Assumptions legitimate just for low-vitality parting ( a couple MeV over the hindrance) Fission flow comes about because of a period advancement in an aggregate space • Fission section properties are resolved at scission, and these properties don't change when pieces are all around isolated.

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What we have done: the formalism utilized 1 - STATIC : compelled Hartree-Fock-Bogoliubov strategy with Multipoles that are not obliged go up against qualities that limit the aggregate vitality. Utilization of the D1S Gogny drive: mean-field and matching relationships are dealt with on a similar balance

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2 - DYNAMICS : Time-subordinate Generator Coordinate Method with the same than in HFB. Utilizing the Gaussian Overlap Approximation it prompts to a Schrödinger-like condition: With this technique the aggregate Hamiltonian is completely inferred by minuscule fixings and the Gogny D1S compel

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The way we continue 1) Potential Energy Surface (q20,q30) from HFB figurings, from circular shape to expansive disfigurements 2) assurance of the scission setups in the (q20,q30) plane 3) computation of the properties of the FF at scission - - 4) mass disseminations from time-subordinate estimations

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Potential vitality surfaces 238 U 226 Th 256 Fm * SD minima in 226 Th and 238 U (and not in 256 Fm) SD minima washed out for N > 156 J.P. Delaroche et al., NPA 771 (2006) 103. * Third least in 226 Th * Different topologies of the PES; rivalries amongst symmetric and hilter kilter valleys

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Definition of the scission line No topological meaning of scission focuses. Distinctive definitions: * E nucl under 1% of the E coul L.Bonneau et al., PRC75 064313 (2007) * thickness in the neck  < 0.01 fm - 3 + drop of the vitality ( 15 MeV) + abatement of the hexadecapole minute ( 1/3) J.- F. Berger et al., NPA428 23c (1984); H. Goutte et al., PRC71 024316 (2005)

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Prompt neutron discharge: correlation with exp. information J.E. Gindler PRC19 1806 (1979) Underestimation presumably because of the characteristic excitation vitality not considered here. Be that as it may, great subjective assention N. Dubray, H. Goutte, J.- P. Delaroche, Phys. Rev. C77 (2008)

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DYNAMICAL EFFECTS ON MASS DISTRIBUTION Comparisons in the vicinity of 1D and « dynamical » appropriations • Same area of the maxima Due to properties of the potential vitality surface (surely understood shell impacts ) • Spreading of the top Due to dynamical impacts : ( connection between the 2 aggregate Modes by means of potential vitality surface and tensor of inactivity) • Good concurrence with analysis « 1D » « DYNAMICAL » WAHL Yield H. Goutte, J.- F. Berger, P. Casoli and D. Gogny, Phys. Rev. C71 (2005) 024316

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Experimental data required We require information on splitting part properties; Ex: Kinetic Energy, Excitation vitality, Prompt  and n outflow, Polarisation, Yields … with a distinguishing proof in mass and charge !!! Bolster the examinations @ILL (TKE … ) @GANIL (ex: program of F. Rejmund) elise@FAIR

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The future New elements: * To expand the quantity of aggregate directions (new splitting modes) * To think about in more subtle elements the underlying state * To consider the pre-scission vitality New developpements: * to dispose of the adiabatic suspicion: part of the "scattering" in the splitting procedure A PhD theory is proposed Work in a joint effort with D. Lacroix and C. Simenel

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This review is a piece of the program of the DANSER cooperation: C. Simenel, D. Lacroix, H. Goutte Dynamical Approaches for Nuclear Structure and low –Energy Reactions If somebody is keen on going along with us, invite !! Heloise.goutte@cea.fr