Properties of correlated fission fragments from neutron induced fission of Np-237 at incident neutron energies between 200 keV and 100 MeV
| Autor: | Connolly, D., Montoya, K. B., Duke, D. L., Greife, U., Lovell, A. E., Mosby, S., Prokop, C., Rudziensky, E., Schmitt, K., Winkelbauer, J. |
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| Rok vydání: | 2021 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | Neutron-induced fission of $^{237}$Np has been measured over a wide range of incident neutron energies using a twin Frisch-gridded ionization chamber (TFGIC) and a thin-backed $^{237}$Np target. These measurements were performed at the Los Alamos Neutron Science Center - Weapons Neutron Research (LANSCE - WNR) facility, which provides a collimated beam of neutrons with energies ranging from 100s of keV to 100s of MeV. The data were analyzed using the double-energy ($2E$) method, with mass-dependent corrections for prompt-fission neutrons and pulse height defect. Pre- and post-neutron evaporation average total kinetic energy ($\langle TKE\rangle$) values are reported for 54 incident neutron energies in the energy range $0.20 \le E_n \le 100.0$ MeV and compared to existing data and evaluations. Pre- and post-neutron evaporation mass yields were extracted with a full width at half maximum (FWHM) resolution of 4u and compared to existing data and evaluations. The present $\langle TKE\rangle$ and mass yield data agree with previous results and also with statistical models of $^{237}$Np$(n,f)$ at incident neutron energies between $E_n = 0.2 - 20.0$ MeV. A flattening of the $\langle TKE\rangle$ data is observed (relative to the prediction of the GEF model) above $E_n = 20.0$ MeV. However, the interpretation of this discrepancy is unclear as the analysis method's neglect of incomplete momentum transfer at high energies, as well as pre-equilibrium pre-fission phenomena likely have a significant impact on the measurement at such high incident neutron energies. Comment: 28 pages, 13 captioned figures, 4 tables, submitted to Journal of Physics G |
| Databáze: | arXiv |
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