0474573 - ÚJF 2018 RIV US eng J - Článek v odborném periodiku
Firestone, R. B. - Belgya, T. - Krtička, M. - Bečvář, F. - Szentmiklosi, L. - Tomandl, Ivo
Thermal neutron capture cross section for Fe-56(n,gamma).
Physical Review C. Roč. 95, č. 1 (2017), č. článku 014328. ISSN 2469-9985. E-ISSN 2469-9993
Grant CEP: GA ČR GA13-07117S; GA MŠMT LM2015056
Institucionální podpora: RVO:61389005
Klíčová slova: neutron cross section * gamma gamma-coincidence data
Obor OECD: Nuclear physics
Impakt faktor: 3.304, rok: 2017

The Fe-56(n,gamma) thermal neutron capture cross section and the Fe-57 level scheme populated by this reaction have been investigated in this work. Singles gamma-ray spectra were measured with an isotopically enriched Fe-56 target using the guided cold neutron beam at the Budapest Reactor, and gamma gamma-coincidence data were measured with a natural Fe target at the LWR-15 research reactor in Rez, Czech Republic. A detailed level scheme consisting of 448 gamma rays populating/depopulating 97 levels and the capture state in Fe-57 has been constructed, and approximate to 99% of the total transition intensity has been placed. The transition probability of the 352-keV gamma ray was determined to be P-gamma(352) = 11.90 +/- 0.07 per 100 neutron captures. The Fe-57 level scheme is substantially revised from earlier work and approximate to 33 previously assigned levels could not be confirmed while a comparable number of new levels were added. The Fe-57 gamma-ray cross sections were internally calibrated with respect to H-1 and S-32 gamma-ray cross section standards using iron(III) acetylacetonate (C15H21FeO6) and iron pyrite (FeS2) targets. The thermal neutron cross section for production of the 352-keV gamma-ray cross section was determined to be sigma(gamma)(352) = 0.2849 +/- 0.015 b. The total Fe-56(n,gamma) thermal radiative neutron cross section is derived from the 352-keV gamma-ray cross section and transition probability as sigma(0) = 2.394 +/- 0.019 b. A least-squares fit of the gamma rays to the level scheme gives the Fe-57 neutron separation energy S-n = 7646.183 +/- 0.018 keV.
Trvalý link: http://hdl.handle.net/11104/0271594