Excitation energy dependence of photofissility in preactinide nuclei

Guaraldo, C.; Lucherini, V.; Sanctis, E. De; Iljinov, A. S.; Mebel, M. V.; Nigro, S. Ló

doi:10.1007/bf02820532

Cited by 29 publications

(21 citation statements)

References 6 publications

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“…Photofission probabilities of Bi over a wide range of photon energies and inferred excitations E showed a saturation at higher energies, with Py ceasing to rise as naively expected [28]. Detailed statistical calculations confirm that such a saturation is predicted through an intranuclear cascade calculation [29]. It would be valuable to carry through such a computation for the wide range of pion data shown here, to see if we are also reaching some maximum nuclear excitation E.…”

Section: Binary Fissionsupporting

confidence: 54%

Mass and energy dependence of pion-induced fission

Peterson

deBarros

deSouza

et al. 1995

Z. Physik A - Hadrons and Nuclei

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Abstract. Data for fission induced by pi meson beams from 80 to 500 MeV are presented for nuclei from Fe through Pu as measured by solid state track detectors. The general trends for binary fission with ~+ are reproduced fairly well by a calculation in the 'high excitation' limit with standard level density and fission barrier parameters, but 7c-data are underpredicted. A universal dependence of the binary fission probabilities with the fissility (Z + 1)2/A is found to be valid for both pion beam charges for all beam energies below the delta resonance. Probabilities for observing three fragments with ~+ are not reproduced by a ternary fission application of the model found to work for binary fission.

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Section: Binary Fissionsupporting

confidence: 54%

Mass and energy dependence of pion-induced fission

Peterson

deBarros

deSouza

et al. 1995

Z. Physik A - Hadrons and Nuclei

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“…The calculations of Ref. [26] for photoabsorption on 197 Au and 208 Pb nuclei, performed in the framework of another version of INC model [24], demonstrate that E ⋆ does not exceed 80 MeV for 30 ≤ E γ ≤ 140 MeV. In this E γ region the fissility P f of 197 Au and 208 Pb nuclei becomes noticeable (P f ∼ 0.01 and 0.1, respectively), so one should expect the evaporation-fission competition.…”

Section: Excitation and Decay Of Residual Nucleimentioning

confidence: 99%

Particle emission following Coulomb excitation in ultrarelativistic heavy-ion collisions

Pshenichnov

Mishustin

Bondorf³

et al. 1999

Phys. Rev. C

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We study nuclear reactions induced by virtual photons associated with Lorentz-boosted Coulomb fields of ultrarelativistic heavy ions. Evaporation, fission and multifragmentation mechanisms are included in a new RELDIS code, which describes the deexcitation of residual nuclei formed after single and double photon absorption in peripheral heavy-ion collisions. Partial cross sections for different dissociation channels, including the multiple neutron emission ones, are calculated and compared with data when available. Rapidity and transverse momentum distributions of nucleons, nuclear fragments and pions, produced electromagnetically, are also calculated. These results provide important information for designing large-rapidity detectors and zero-degree calorimeters at RHIC and LHC. The electromagnetic dissociation of nuclei imposes some constrains on the investigation of exotic particle production in γγ fusion reactions. 25.70.De, 24.10.Lx PACS

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“…The result obtained in Ref. [40] clearly exhibits a broader shape with an average photoexcitation energy ͗E * ͘ϳ78 MeV (dashed arrow) higher than the one achieved from the MCMC model ͗E * ͘ϳ46 MeV (solid arrow). The difference between these results could be ascribed to the Pauli-blocking mechanism, indicating that in our approach the depletion of the Fermi sphere is more re- strictive, leading to a narrower distribution with a lower and more accurate average value.…”

Section: E the Energetic Criterion To Stop The Cascade Processmentioning

confidence: 71%

“…4 we show the normalized excitation energy distributions for the cascade ␥ + 209 Bi at 140 MeV from the MCMC model calculations (solid histograms) and from Ref. [40] (dashed histograms). The result obtained in Ref.…”

Section: E the Energetic Criterion To Stop The Cascade Processmentioning

confidence: 99%

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Photonuclear reactions at intermediate energies investigated via the Monte Carlo multicollisional intranuclear cascade model

et al. 2004

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The Monte Carlo multicollisional (MCMC) intranuclear cascade model is used to study photonuclear reactions at intermediate energies ͑20ഛ E ␥ ഛ 140 MeV͒. This version of the code differs from previous versions in the following aspects: (i) the quasideuteron model of photoabsorption is consistently included by taking into account relative momentum correlations of the neutron-proton pair in a relativistic kinematics; (ii) a realistic treatment of the Pauli-blocking mechanism at the initial photoabsorption and at each binary nucleon-nucleon scattering during the cascade process is incorporated throughout the calculations; (iii) a criterion based on energy considerations is required by the end of the cascade. Differently from other transport models used so far, which are based on a randomly generated nuclear ground state with a stochastic treatment of the Pauli blocking, the present model incorporates a shell constrained momentum space of the nucleons which is preserved as the cascade evolves along time. The transition between the pre-equilibrium and evaporation phases is energetically determined, allowing the description of the cascade process without any free parameter, such as some ambiguous stopping time parameters adopted in similar time-structured cascade models. The occupation number distribution after the cascade corresponds to a typical Fermi distribution at a finite nuclear temperature, and the long-standing spurious depletion of the Fermi sphere, usually present in other cascade models, no longer appears. The Pauli-blocking factors are calculated and compared with previous approaches based on Fermi gas level density calculations. The evaporation-fission process of the compound nucleus is described in the framework of a Monte Carlo algorithm. Experimental data of the total photoabsorption cross section and the neutron multiplicities for Sn, Ce, Ta, and Pb in the 20-140-MeV range are described fairly well by the present calculations.

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Excitation energy dependence of photofissility in preactinide nuclei

Cited by 29 publications

References 6 publications

Mass and energy dependence of pion-induced fission

Mass and energy dependence of pion-induced fission

Particle emission following Coulomb excitation in ultrarelativistic heavy-ion collisions

Photonuclear reactions at intermediate energies investigated via the Monte Carlo multicollisional intranuclear cascade model

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