Cascade-Exciton Model Analysis of Nucleon-Induced Fission Cross Sections of Lead and Bismuth at 45- to 500-MeV Energies

Prokofiev, Alexander V.; Mashnik, S. G.; Sierk, Arnold J.

doi:10.13182/nse99-a2019

Cited by 21 publications

(14 citation statements)

References 22 publications

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“…Our modified version slightly improves on the standard INCL4 results and gives similar results to the CEM model of Ref. [34], as reported in Ref. [33].…”

Section: Residue Production In Pion-induced Reactionssupporting

confidence: 71%

Pion physics in the Liège intranuclear cascade model

Aoust

2006

Phys. Rev. C

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The implementation of π production in the Liège intranuclear cascade model (INCL4) for spallation reactions is revisited to alleviate the overestimate of the π yield. Three modifications are proposed for this purpose: a better πN cross section at high energy, the introduction of a π average potential, and the modification of the average mass of the resonance. The π potential is determined from a global fit of a set of data bearing on π production in proton-induced reactions, on π -nucleus and absorption cross sections, and on proton production in π -induced reactions. The resulting π potential is poorly determined in the nuclear interior and agrees with the phenomenological optical-model potentials in the surface region. With these modifications, the predictions of the INCL4 model concerning π production cross sections in proton-induced reactions are considerably improved. Predictions of the improved version for π -nucleus reaction and absorption cross sections and for proton, residue, and fission cross sections in π -induced reactions are also presented and shown to give reasonably good agreement. Neutron production and some aspects of fission in π -induced reactions are also investigated and reasonably well predicted. Effects on the modifications on observables, which are not directly linked with π 's, such as the neutron yield and the residue mass and charge spectra in proton-induced reactions are also investigated and shown to improve the description of these observable quantities. Several results on π production and the relative insentivity to the π potential in the nuclear interior are shown to be consistent with the fact that most π 's are not produced in early collisions. Importance of rescattering in π absorption on nuclei is also pointed out. A comparison is made with the so-called -hole model. Residual discrepancies are identified and are interpreted as due to the lack of π interaction with two nucleons at low energy, to the neglect of quantum motion effects, and to a possible underestimate of rescattering.

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“…Our modified version slightly improves on the standard INCL4 results and gives similar results to the CEM model of Ref. [34], as reported in Ref. [33].…”

Section: Residue Production In Pion-induced Reactionssupporting

confidence: 71%

Pion physics in the Liège intranuclear cascade model

Aoust

2006

Phys. Rev. C

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“…3,13) We also made a number of refinements in the calculation of the fission channel, as described in. 4,14,15) The original version of CEM95…”

Section: Resultsmentioning

confidence: 99%

“…We have performed calculations for neutron-and protoninduced reactions on several targets, focusing on being energy-independent, which is the same as ignoring the ground-state shell effect on the level density at the saddle point (see 14) ). An example of these calculations with the original and an improved version of CEM as described in 14) is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…An example of these calculations with the original and an improved version of CEM as described in 14) is shown in Fig. 1.…”

Section: Resultsmentioning

confidence: 99%

“…For instance, we are not satisfied with the situation that in the improved versions of the CEM we still have an additional input parameter to describe fission cross sections: either , in the approach 14) illustrated in Fig. 1, or i p T B i r , in our later version.…”

Section: Further Workmentioning

confidence: 97%

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Recent Developments of the Cascade-Exciton Model of Nuclear Reactions

Mashnik

Sierk

2002

Journal of Nuclear Science and Technology

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Recent developments of the Cascade-Exciton Model (CEM) of nuclear reactions are described. The improved cascade-exciton model as implemented in the code CEM97 differs from the CEM95 version by incorporating new approximations for the elementary cross sections used in the cascade, using more precise values for nuclear masses and pairing energies, using corrected systematics for the level-density parameters, and several other refinements. We have improved algorithms used in many subroutines, decreasing the computing time by up to a factor of 6 for heavy targets. We describe a number of further improvements and changes to CEM97, motivated by new data on isotope production measured at GSI. This leads us to CEM2k, a new version of the CEM code. CEM2k has a longer cascade stage, less preequilibrium emission, and evaporation from more highly excited compound nuclei compared to earlier versions. CEM2k also has other improvements and allows us to better model neutron, radionuclide, and gas production in ATW spallation targets. The increased accuracy and predictive power of the code CEM2k are shown by several examples. Further necessary work is outlined.

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