Monte Carlo approach to sequential neutron emission from fission fragments

“…We simulate the evaporation chain in a manner conceptually similar to the method of Lemaire et al [31] for 252 Cf(sf) and 235 U(n, f ). After neutron emission is no longer energetically possible, FREYA simulates the sequential emission of photons by a similar method [7], see also Ref.…”

Section: Fragment De-excitationmentioning

confidence: 99%

Event-by-event evaluation of the prompt fission neutron spectrum from239Pu(n,f)

et al. 2012

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“…Properties of prompt fission neutrons and γ rays, emitted before the weak decays of the fission fragments toward stability, are important for both nuclear technologies and a better understanding of the fission process. Significant effort has been directed to the study of prompt fission neutron properties [1][2][3][4][5], in particular the average spectrum and multiplicity, but the properties of the prompt γ rays have been less studied. Hence, uncertainties on nuclear data needed for fast reactors are large, given that even in the well known thermal power reactors, the local γ heating can be under predicted by up to 30% [6].…”

mentioning

confidence: 99%

Properties of prompt-fissionγrays

et al. 2014

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In a Monte-Carlo Hauser-Feshbach statistical framework, we describe spectra, average multiplicities, average energy and multiplicity distributions of the prompt γ rays produced in the thermal neutron-induced fission of 235 U and 239 Pu, and the spontaneous fission of 252 Cf. Comparisons against recent experimental data show reasonable agreement in all cases investigated, after adjustment of the initial spin distribution in the fission fragments. In particular, when we include in the calculation the Doppler broadening we obtain a qualitatively good description of the measured low-energy spectra, where contributions from collective discrete transitions in specific fragments can be identified. At higher energies, both the calculated neutron and γ-ray spectra are softer than experimental data. The impact of selected model parameters on the prompt neutron and γ-ray spectra is analyzed. Finally, we present prompt γ spectrum and multiplicity distribution for the neutron-induced fission of 235 U for 5.5 MeV neutron incident energy, just below the threshold for second-chance fission.

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“…In addition to our own work along these lines, a conceptually similar approach is being developed at Los Alamos by Talou [5,6]. Such treatments give access to essentially any conceivable correlation observable and thus have vastly expanded potential utility.…”

Section: Discussionmentioning

confidence: 99%

Event-by-Event Simulation of Induced Fission

Vogt¹,

Randrup²,

Escher³

et al. 2008

AIP Conference Proceedings

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Abstract. We are developing a novel code that treats induced fission by statistical (or Monte-Carlo) simulation of individual decay chains. After its initial excitation, the fissionable compound nucleus may either deexcite by evaporation or undergo binary fission into a large number of fission channels each with different energetics involving both energy dissipation and deformed scission prefragments. After separation and Coulomb acceleration, each fission fragment undergoes a succession of individual (neutron) evaporations, leading to two bound but still excited fission products (that may further decay electromagnetically and, ultimately, weakly), as well as typically several neutrons. (The inclusion of other possible ejectiles is planned.) This kind of approach makes it possible to study more detailed observables than could be addressed with previous treatments which have tended to focus on average quantities. In particular, any type of correlation observable can readily be extracted from a generated set of events. With a view towards making the code practically useful in a variety of applications, emphasis is being put on making it numerically efficient so that large event samples can be generated quickly. In its present form, the code can generate one million full events in about 12 seconds on a MacBook laptop computer. The development of this qualitatively new tool is still at an early stage and quantitative reproduction of existing data should not be expected until a number of detailed refinement have been implemented.

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Monte Carlo approach to sequential neutron emission from fission fragments

Cited by 107 publications

References 15 publications

Event-by-event evaluation of the prompt fission neutron spectrum from239Pu(n,f)

Event-by-event evaluation of the prompt fission neutron spectrum from239Pu(n,f)

Properties of prompt-fissionγrays

Event-by-Event Simulation of Induced Fission

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