WFRF:(Solders M.)
Sökning: WFRF:(Solders M.) > (2020-2024) > Prompt fission neut...
- 10 av 16
- Föregående post
- Nästa post
- Till träfflistan
Prompt fission neutron yields in thermal fission of U-235 and spontaneous fission of Cf-252
-
- Al-Adili, Ali (författare)
- Uppsala universitet,Tillämpad kärnfysik
-
- Tarrío, Diego (författare)
- Uppsala universitet,Tillämpad kärnfysik
-
- Jansson, Kaj, 1987- (författare)
- Uppsala universitet,Tillämpad kärnfysik
- visa fler...
- visa färre...
- (creator_code:org_t)
- American Physical Society (APS), 2020
- 2020
- Engelska.
- Ingår i: Physical Review C. - : American Physical Society (APS). - 2469-9985 .- 2469-9993. ; 102:6
- Tidskriftsartikel (refereegranskat)
Abstract
Ämnesord
Stäng
- Background: The sharing of excitation energy between the fission fragments is one of the key issues in studying nuclear fission. One way to address this is by studying prompt-fission neutron multiplicities as a function of other fission observables such as the mass, (nu) over bar (A). These are vital benchmark data for both fission and nuclear deexcitation models, putting constrains on the fragment excitation energy and hence on the competing prompt neutron/gamma-ray emission. Despite numerous detailed studies, recent measurements done at JRC-Geel with the SCINTIA array in the epithermal region show surprisingly strong discrepancies to earlier thermal fission data and the Wahl systematics. Purpose: The purpose was to perform measurements of the prompt-fission neutron multiplicity, as a function of fragment mass and total kinetic energy (TKE), in U-235(n(th), f) and Cf-252(sf), to verify and extend the SCINTIA results. Another goal was to validate the analysis methods, and prepare for planned investigations at excitation energies up to 5.5 MeV. Methods: The experiments were conducted at the former 7 MV Van de Graaff facility in JRC-Geel, using a Twin Frisch-Grid Ionization Chamber and two liquid scintillation detectors. A neutron beam with an average energy of 0.5 MeV was produced via the Li-7(p,n) reaction. The neutrons were thermalized by a 12 cm thick block of paraffin. Digital data acquisition systems were utilized. Comprehensive simulations were performed to verify the methodology and to investigate the role of the mass and energy resolution on measured (nu) over bar (A) and (nu) over bar (TKE) values. The simulation results also revealed that the partial derivative(nu) over bar/partial derivative A and partial derivative(TKE) over bar/partial derivative(nu) over bar are affected by the mass and energy resolution. However, the effect is small for the estimated resolutions of this work. Detailed Fluka simulations were performed to calculate the fraction of thermal neutron-induced fission, which was estimated to be about 98%. Results: The experimental results on (nu) over bar (A) are in good agreement with earlier data for Cf-252(sf). For U-235(n(th), f), the (nu) over bar (A) data is very similar to the data obtained with SCINTIA, and therefore we verify these disclosed discrepancies to earlier thermal data and to the Wahl evaluation. The experimental results on (nu) over bar (TKE) are also in agreement with the data at epithermal energies. For Cf-252(sf) a slope value of partial derivative(TKE) over bar/partial derivative(nu) over bar = (-12.9 f 0.2) MeV/n was obtained. For U-235(n(th), f) the value is (-12.0 +/- 0.1) MeV/n. Finally, the neutron spectrum in the center-of-mass system was derived and plotted as a function of fragment mass. Conclusions: This work clearly proves the lack of accurate correlation between fission fragment and neutron data even in the best-studied reactions. The new results highlight the need of a new evaluation of the prompt-fission multiplicity for U-225(n(th), f).
Ämnesord
- NATURVETENSKAP -- Fysik -- Subatomär fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Subatomic Physics (hsv//eng)
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
- 10 av 16
- Föregående post
- Nästa post
- Till träfflistan
Hitta mer i SwePub
- Av författaren/redakt...
- Al-Adili, Ali
- Tarrío, Diego
- Jansson, Kaj, 19 ...
- Rakopoulos, Vasi ...
- Solders, Andreas ...
- Pomp, Stephan, 1 ...
- visa fler...
- Göök, Alf
- Hambsch, F-J
- Oberstedt, S.
- Vidali, M.
- visa färre...
- Om ämnet
-
- NATURVETENSKAP
- NATURVETENSKAP
- och Fysik
- och Subatomär fysik
- Artiklar i publikationen
- Physical Review ...
- Av lärosätet
- Kungliga Tekniska Högskolan
- Uppsala universitet
Sök utanför SwePub
- Sök vidare i:
- Google Book Search
- Google Scholar
Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.
- Copyright © LIBRIS - Nationella bibliotekssystem
- LIBRIS.kb.se
