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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.
A Transparent Detector for n_TOF Neutron Beam Monitoring
S. Andriamonje,M. Calviani,Y. Kadi,R. Losito,V. Vlachoudis,E. Berthoumieux,F. Gunsing,A. Giganon,Y. Giomataris,C. Guerrero,R. Sarmento,P. Schillebeeckx,P. Siegler 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
In order to obtain high precision cross-section measurements using the time-of-flight technique, it is important to know with good accuracy the neutron uence at the measuring station. The detector dedicated to these measurements should be placed upstream of the detectors used for capture and fission cross-section measurements. The main requirement is to reduce the material of the detector as much as possible, in order to minimize the perturbation of the neutron beam and, especially, the background produced by the device itself. According to these considerations, a new neutron detector equipped with a small-mass device based on MicroMegas "Micro-bulk" technology has been developed as a monitoring detector for the CERN n TOF neutron beam. A description of the different characteristics of this innovative concept of transparent detector for neutron beam monitoring is presented. The result obtained in the commissioning of the new spallation targetof the n TOF facility at CERN is shown, compared with simulations performed with the FLUKA code.
A New 2D-micromegas Detector for Neutron Beam Diagnostic at n_TOF
S. Andriamonje,M. Calviani,Y. Kadi,R. Losito,V. Vlachoudis,E. Berthoumieux,F. Gunsing,Y. Giomataris,T. Papaevangelou,C. Guerrero,N. Colonna,C. Weiss 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
A novel detector for 2D neutron beam diagnostic has been jointly developed by CERN andCEA in the framework of the n TOF Collaboration for investigation of the neutron beam spatial characteristics, namely position and profile as a function of the neutron energy. The detector is based on the already established MicroMegas "Bulk" technology and has been evolved from the one used for the CAST (CERN Axion Solar Telescope) experiment but equipped with an appropriate neutron/charged particle converter for neutron detection. The experimental results obtained in the 2009 commissioning run of the n_TOF facility and a comparison with simulations performed by means of FLUKA code are given, together with future perspectives and possible applications for this original type of neutron detector.