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Neutron Capture on <SUP>209</SUP>Bi: Determination of the Production Ratio of ^(210m)Bi/^(210g)Bi
F. Gunsing,E. Berthoumieux,A. Borella,T. Belgya,L. Szentmiklosi,P. Schillebeeckx,J. C. Drohe,R. Wynants,N. Colonna,S. Marrone,G. Tagliente,R. Terlizzi,C. Domingo-pardo,J. Tain,T. Martinez,C. Massimi,P 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
Neutron capture on ^(209)Bi produces either an isomeric state ^(210m)Bi with a half life of 3×10^6 years, or the ground state ^(210g)Bi which decays with a half life of 5 days to the alpha emitter ^(210)Po. Therefore the neutron capture cross section ratio ^(209)Bi(n,γ) ^(210m)^(Bi)/^(210g)Bi plays an important role in predicting the short- and long-term radio-toxicity produced by ^(209)Bi under neutron irradiation. This ratio is dependent on the neutron energy. We have measured this ratio for cold neutrons at the cold neutron beam facility of the Budapest Neutron Centre by observing the population of the ground- and the metastable state using high resolution gamma-ray spectroscopy. The same technique hasbeen used at the pulsed white neutron source GELINA of the IRMM, Geel in combination with the neutron time-of-flight technique. Results for the neutron-energy dependent branching ratio will be presented. In addition we performed simulations using a statistical decay code.
Study of Photon Strength Function of Actinides: the Case of ^(235)U, ^(238)Np and ^(241)Pu
C. Guerrero,F. Alvarez-Velarde,D. Cano-Ott,T. Martinez,E. Mendoza,D. Villamarin,N. Colonna,M. H. Meaze,S. Marrone,G. Tagliente,R. Terlizzi,F. Belloni,U. Abbondanno,K. Fujii,P. M. Milazzo,C. Moreau,G. 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
The decay from excited levels in medium and heavy nuclei can be described in a statisticalapproach by means of Photon Strength Functions and Level Density distributions. The study of electromagnetic cascades following neutron capture based on the use of high eciency detectors has been shown to be well suited for probing the properties of the Photon Strength Function of heavy (high level density) and/or radioactive (high background) nuclei. In this work we have investigated for the first time the validity of the recommended PSF of actinides, in particular ^(235)U, ^(238)Np and ^(241)Pu. Our study includes the search for resonance structures in the PSF below S_n and draws conclusions regarding their existence and their characteristics in terms of energy, width and electromagnetic nature.
D. Cano-Ott,F. Alvarez-Velarde,E. Gonzalez-Romero,C. Guerrero,T. Martinez,E. Mendoza,D. Villamarin,M. C. Vicente,U. Abbondanno,N. Colonna,M. H. Meaze,S. Marrone,G. Tagliente,R. Terlizzi,F. Belloni,K. 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
The successful development of advanced nuclear systems for sustainable energy production and nuclear waste management depends on high quality nuclear data libraries. Recent sensitivity studies and reports [1][2][3] have identified the need for substantially improving the accuracy of neutron cross-section data for minor actinides. The n_TOF collaboration has initiated an ambitious experimental program for the measurement of neutron capture cross sections of minor actinides. Two experimental setups have been constructed for this purpose: a Total Absorption Calorimeter (TAC) [4] for measuring neutron capture cross-sections of low-mass and/or radioactive samples and a set of two low neutron sensitivity C_6D_6 detectors for the less radioactive materials.