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- Ryzhov, I.V., et al.
(författare)
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Fragment-mass distributions in neutron-induced fission of 232Th and 238U at 33, 45, and 60 MeV
- 2011
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 83:5, s. 054603-
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Tidskriftsartikel (refereegranskat)abstract
- We have measured fission fragment-mass yields for neutron-induced fission of Th-232 and U-238 at energies 32.8, 45.3, and 59.9 MeV. The experiments were done at quasimonoenergetic neutron beams of the Cyclotron Research Center at Louvain-la-Neuve. To detect the fission fragments, a multisection Frisch-gridded ionization chamber was used. The measurement and data analysis techniques are discussed in detail. The obtained mass yields are compared to model calculations with the intermediate-energy nuclear reaction code MCFX. The MCFX code is used to calculate the fraction of fissioning nuclei after cascade, preequilibrium, and statistical reaction stages. The formation of mass distributions is considered as a result of oscillations of the mass-asymmetry degree of freedom in the potential well calculated with the temperature-dependent shell correction method. The experimental results as well as the results of the model calculations demonstrate that the probability of symmetric fission increases with incident neutron energy for both nuclei. The comparison also shows that the symmetric fission is more enhanced for thorium than for uranium with increasing neutron energy. We also compare U-238 results with available experimental data; the Th-232 data were measured for the first time.
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- Simutkin, Vasily D., et al.
(författare)
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Experimental Neutron-induced Fission Fragment Mass Yields of Th-232 and U-238 at Energies from 10 to 33 MeV
- 2014
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Ingår i: Nuclear Data Sheets. - : Elsevier BV. - 0090-3752 .- 1095-9904. ; 119, s. 331-333
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Tidskriftsartikel (refereegranskat)abstract
- Development of nuclear energy applications requires data for neutron-induced reactions for actinides in a wide neutron energy range. Here we describe measurements of pre-neutron emission fission fragment mass yields of Th-232 and U-238 at incident neutron energies from 10 to 33 MeV. The measurements were done at the quasi-monoenergetic neutron beam of the Louvain-la-Neuve cyclotron facility CYCLONE; a multi-section twin Frisch-gridded ionization chamber was used to detect fission fragments. For the peak neutron energies at 33, 45 and 60 MeV, the details of the data analysis and the experimental results were published in Ref. [1]. In this work we present data analysis in the low-energy tail of the neutron energy spectra. The preliminary measurement results are compared with available experimental data and theoretical predictions.
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- Ryzhov, I. V., et al.
(författare)
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Measurement of Fragment Mass Yields in Neutron-induced Fission of (232)Th and (238)U at 33, 45 and 60 MeV
- 2011
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Ingår i: Journal of the Korean Physical Society. - : Korean Physical Society. - 0374-4884 .- 1976-8524. ; 59:2, s. 1864-1867
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Tidskriftsartikel (refereegranskat)abstract
- Incineration of spent nuclear fuel in Accelerator Driven Systems requires nuclear data on neutron-induced fission of actinides at energies above 20 MeV - the upper limit of conventional evaluated nuclear data files. Over the past years, a significant effort has been devoted to measurements of neutron-induced fission cross-sections at intermediate energies but there is a lack of experimental data on fission yields. Here we describe recent measurements of pre-neutron emission fragment mass distributions from intermediate energy neutron-induced fission of (232)Th and (238)U. The measurements have been carried out at the neutron beam of the Louvain-la-Neuve cyclotron facility CYCLONE. Quasi-monoenergetic neutrons with peak energies at 32.8, 45.3 and 59.9 MeV were produced by protons impinging on a thin lithium target. A multi-section Frisch-gridded ionization chamber was used as a fission fragment detector. The measurement results are compared with available experimental data as well as with predictions of the multi-modal random neck-rupture model implemented into the TALYS code.
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