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Neutron Resonance Spectroscopy at GELINA
P. Schillebeeckx,A. Borella,S. Kopecky,C. Lampoudis,C. Massimi,M. Moxon 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
The neutron time-of-flight facility GELINA installed at the JRC-IRMM Geel (B) has been designed to produce cross section data for neutron induced reactions in the resonance region. It is a multi-user facility, providing a pulsed white neutron source, with a neutron energy range between 10 meV and 20 MeV and a time resolution of 1 ns. The research program concentrates on cross section data needs for nuclear energy applications. In this contribution efforts to improve the quality of cross section data in the resonance region are discussed. These efforts include the implementation of self-indication measurements and improved data reduction and resonance analysis procedures. Due to these efforts accurate neutron-induced cross section data and resonance parameters together with their covariance information can be obtained from thermal up to the unresolved resonance region.
Transmission and Capture Measurements for ^(241)Am at GELINA
C. Lampoudis,S. Kopecky,A. Plompen,P. Schillebeeckx,P. Siegler 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
The precise knowledge of cross sections for neutron induced reactions of major and minor actinides is essential for the design of advanced reactors. Furthermore, the present evaluated data files disagree with the results of some recent measurements. Therefore it was decided to perform new transmission and capture measurements for ^(241)Am at GELINA aiming to improve the evaluations. For the measurements a novel sample preparation method has been employed, for ensuring the homogeneity of the samples. The first results of capture and transmission measurements are consistent with each other, and with recent experimental values, but seem to be inconsistent with the evaluated data files. Before the final results can be reported, a careful characterisation of the americium sample is required.
Evaluation of Neutron Cross Sections for Hafnium in the Resolved Resonance Range
T. Ware,D. Weaver,M. Moxon,C. Dean,R. Hiles,P. Schillebeeckx,S. Kopecky 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
The international High Priority Request list notes: - "In the nuclear industry hafnium is used as neutron absorbing material to regulate the fission process. Interpretation of critical experiments with UOx fuel conducted by CEA in the AZUR zero-power reactors has shown systematic underestimation of the reactivity worth that may be attributed to an overestimated natural hafnium capture cross section in the epi-thermal energy range"To service the request for improved resonance data a PhD project has:-a) Improved REFIT R-matrix evaluation code.b) Obtained hafnium oxide samples enriched in Hf176, 177, 178, 179 isotopes.c) Gained support from NUDAME and EUFRAT projects.d) Prepared enriched and natural Hf samples.e) Performed capture and transmission Time of Flight measurements at the GELINA linear accelerator.f) Analysed the capture counts to generate yields using AGS and AGL codes.g) Used REFIT to perform least squares analysis of GELINA measurements.(Included previous ORNL, Harwell and RPI transmissions and capture yields.)h) Submitted results to EXFOR.i) Included resolved resonance parameters in JEFF evaluations taking the resolved range to over 1keV. j) Tested evaluations with suitable benchmarks.k) Passed resolved resonance data to CEA Cadarache for unresolved analysis.Resultant Hf evaluations will be included in JEFF3.2.
Database for Time-of-flight Spectra Including Covariances
N. Otuka,A. Borella,S. Kopecky,C. Lampoudis,P. Schillebeeckx 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
A data format for time-of-flight spectra (transmission, reaction andself-indication yields) and their covariance matrices based on the AGS(Analysis of Geel Spectra) format is discussed in collaboration betweenEC-JRC IRMM and IAEA-NDS for the EXFOR library. Experimentalists areencouraged to consider the uncertainty propagation following the AGSprinciple and submission of their data to the International Networks NuclearReaction Data Centres (NRDC) for EXFOR compilation using a proposedtemplate.
Lee Jounghwa,Lee Young-Ouk,Park Tae-Sun,Schillebeeckx Peter,홍승우 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.80 No.10
Post-neutron emission fssion product mass distributions are calculated by using pre-neutron emission fssion product yields (FPYs) and neutron multiplicity. A semi-empirical model is used to calculate the pre-neutron FPY, frst. Then the neutron multiplicity for each fssion fragment mass is used to convert the pre-neutron FPY to the post-neutron FPY. In doing so, assumptions are made for the probability for a pre-emission fssion fragment with a mass number A∗ to decay to a postemission fragment with a mass number A. The resulting post-neutron FPYs are compared with the data available. The systems where the experimental data of not only the pre- and post-neutron FPY but also neutron multiplicity are available are the thermal neutron-induced fssion of 233U, 235U and 239Pu. Thus, we applied the model calculations to these systems and compared the calculation results with those from the GEF and the data from the ENDF and the EXFOR libraries. Both the pre- and post-neutron fssion product mass distributions calculated by using the semi-empirical model and the neutron multiplicity reproduce the overall features of the experimental data.
C. Massimi,A. Borella,S. Kopecky,C. Lampoudis,P. Schillebeeckx,M. C. Moxon,G. Vannini 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
Transmission, capture and self-indication measurements on^(197)Au have been performed at the neutron time-of-flightfacility GELINA, operated by the European Commission, at EU-JRC-IRMM inBelgium. Part of this work was performed within the framework of the EFNUDATproject, with the objective to improve resonance parameters for the ^(197)Au(n, γ) cross section. Resonance parameters, i.e.,energy, spin, parity, neutron and radiation width, have been deduced in theenergy domain up to 200 eV. A comparison with results of measurementsperformed at RPI and at n_TOF shows a good agreement betweenthe data sets. In particular the nuclear resonance parameters, of the firsts-wave resonance at 4.9 eV, extracted at RPI are in very good agreement withthe results of the present work.
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.
Sirakov, I.,Capote, R.,Gritzay, O.,Kim, H. I.,Kopecky, S.,Kos, B.,Paradela, C.,Pronyaev, V. G.,Schillebeeckx, P.,Trkov, A. Springer 2017 European Physical Journal A Vol.53 No.10
<P>Cross sections for neutron interactions with U-238 in the energy region from 5 keV to 150 keV have been evaluated. Average total and capture cross sections have been derived from a least squares analysis using experimental data reported in the literature. The resulting cross sections have been parameterised in terms of average resonance parameters maintaining full consistency with results of optical model calculations by using a dispersive coupled channel optical model potential. The average compound partial cross sections have been expressed in terms of transmission coefficients by applying the Hauser-Feshbach statistical reaction theory including width-fluctuations. A generalized single-level representation compatible with the energy-dependent options of the ENDF-6 format has been applied using standard boundary conditions. The results have been transferred into a full ENDF-6 compatible data file.</P>
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.