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. KCI Citation Count: 0
Resonance parameters for neutron-induced reactions on
241
Am below 110 eV have been determined. The parameters result from a resonance shape analysis of transmission and capture data measured at the ...time-of-flight facility GELINA, with the accelerator operating at a 50 Hz repetition rate. The transmission experiments were carried out at a 25 m station using a Li glass scintillator. The capture experiments were performed at a 12.5 m station by applying the total energy detection principle in combination with the pulse height weighting technique using a pair of C
6
D
6
detectors. The normalization of the capture data was determined by a combined least squares adjustment of the transmission and capture data. From the adjusted resonance parameters a capture cross section of 749 ± 35 b for a neutron energy of 0.0253 eV and an average radiation width of 〈
Γ
γ
〉 = 42.0 meV for
s
-wave resonances were obtained. A missing-level analysis for
s
-wave neutron resonances within the statistical model results in compatible values with previous estimates. The neutron widths obtained in this work are approximately 22% larger compared to other experimental data and evaluated data libraries. Also the thermal capture cross section is larger than most of the recommended values. However, the resonance parameter file presented in this work is consistent with results of both integral experiments and of the experimentally determined resonance integrals.
Neutron Resonance Spectroscopy at GELINA Schillebeeckx, P.; Borella, A.; Kopecky, S. ...
Journal of the Korean Physical Society,
08/2011, Letnik:
59, Številka:
2(3)
Journal Article
Recenzirano
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. KCI Citation Count: 7
In the last decade benchmark experiments and simulations, together with newly obtained neutron cross section data, have pointed out deficiencies in evaluated data files of W isotopes. The role of W ...as a fundamental structural material in different nuclear applications fully justifies a new evaluation of super(182, 183, 184, 186)W neutron resonance parameters. In this regard transmission and capture cross section measurements on natural and enriched tungsten samples were performed at the GELINA facility of the EC-JRC-IRMM. A resonance parameter file used as input in the resonance shape analysis was prepared based on the available literature and adjusted in first instance to transmission data.
Recent efforts made at the EC-JRC-IRMM to produce evaluated cross section data files for neutron induced reactions are described as well as the methodology applied in both the resolved and unresolved ...resonance. for the resolved resonance region the paper focuses on a recent evaluation of isotopes present in natural cadmium. For the unresolved resonance region results for gold are presented.
Several studies based on the JEFF-3.1.1 nuclear data library show a systematic overestimation of the critical keff for core configurations of MOX fuel assemblies. The present work investigates ...possible improvements of the C/E results by using new evaluations for Am-241, Pu-239 and Pu-240.
A significant number of new measurements was undertaken by the ANDES “Measurements for advanced reactor systems” initiative. These new measurements include neutron inelastic scattering from 23Na, Mo, ...Zr, and 238U, neutron capture cross sections of 238U, 241Am, neutron induced fission cross sections of 240Pu, 242Pu, 241Am, 243Am and 245Cm, and measurements that explore the limits of the surrogate technique. The latter study the feasibility of inferring neutron capture cross sections for Cm isotopes, the neutron-induced fission cross section of 238Pu and fission yields and fission probabilities through full Z and A identification in inverse kinematics for isotopes of Pu, Am, Cm and Cf. Finally, four isotopes are studied which are important to improve predictions for delayed neutron precursors and decay heat by total absorption gamma-ray spectrometry (88Br, 94Rb, 95Rb, 137I). The measurements which are performed at state-of-the-art European facilities have the ambition to achieve the lowest possible uncertainty, and to come as close as is reasonably achievable to the target uncertainties established by sensitivity studies. An overview is presented of the activities and achievements, leaving detailed expositions to the various parties contributing to the conference.
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. KCI Citation Count: 0
.
The neutron time-of-flight facility n_TOF features a white neutron source produced by spallation through 20GeV/
c
protons impinging on a lead target. The facility, aiming primarily at the ...measurement of neutron-induced reaction cross sections, was operating at CERN between 2001 and 2004, and then underwent a major upgrade in 2008. This paper presents in detail all the characteristics of the new neutron beam in the currently available configurations, which correspond to two different collimation systems and two choices of neutron moderator. The characteristics discussed include the intensity and energy dependence of the neutron flux, the spatial profile of the beam, the in-beam background components and the energy resolution/broadening. The discussion of these features is based on dedicated measurements and Monte Carlo simulations, and includes estimations of the systematic uncertainties of the mentioned quantities.
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