Neutron Inelastic Scattering Cross Section Measurements for 23Na

In March 2011 the final data from measurements for the 23Na(n,n'gamma) reaction were delivered to the CEA - Commissariat à l'Énergie Atomique, Cadarache, France in the context of the EURATOM-CEA collaboration agreement. This report documents that deliverable. The measurement campaign was initiated in response to a request expressed by the CEA at a meeting of the Joint Evaluated Fission and Fusion nuclear data library project in 2007. This meeting took place under the auspices of the Nuclear Energy Agency (Organisation for Economic Co-operation and Development). The CEA supports research for the advanced, Generation-IV type, sodium cooled fast reactor and is engaged in a project to develop a prototype: ASTRID - the advanced sodium test reactor for industrial development. Inelastic scattering cross sections for sodium are of interest to the development of sodium cooled fast reactors. A recent OECD-NEA subgroup analysed the sensitivity of reactor parameters to cross sections and accordingly determined target uncertainties for the nuclear data [1]. Comparing these target uncertainties with the current status of nuclear data uncertainties and covariance data resulted in a list of target priorities. Among these features sodium inelastic scattering for which a target uncertainty of 4% was established for the average cross section in the energy range from threshold to 1.35 MeV. This is approximately seven times as good as the uncertainty for current evaluated data files for this isotope (see OECD-NEA High Priority Request List [2]). At IRMM, the GAINS gamma-array for inelastic neutron scattering was developed with the purpose of measuring cross sections with uncertainties at or below the target uncertainties for nuclides like 23Na using the (n, n'g)-technique [3,4]. In response to the request, a measurement campaign of the 23Na(n,n¿g) reaction was conducted with the GAINS array during 2009-2010, using metallic Na discs of 99.8% purity. The sample and the measurements were made at the Institute for Reference Materials and Measurements in Geel making use of GELINA, the Geel linear electron accelerator that drives a pulsed white neutron source allowing measurements by the neutron time-of-flight technique. A preliminary report of this work was presented earlier [5]. For the experimental work a careful review was made of the gamma-efficiency calibrations and the flux normalization in order to investigate in detail the corrections and the final uncertainties that may realistically be achieved.JRC.DG.D.5-Nuclear physic

Results of time-of-flight transmission measurements for 197Au at a 50 m station of GELINA

Transmission measurements have been performed at the time-of-flight facility GELINA to determine the total cross section for neutron induced reactions in 197Au. The measurements have been carried out at a 50 m transmission station of GELINA with the accelerator operating at 800 Hz. This report provides the experimental details required to deliver the data to the EXFOR data library which is maintained by the Nuclear Data Section of the IAEA and the Nuclear Energy Agency of the OECD. The experimental conditions and data reduction procedures are described. In addition, the full covariance information based on the AGS concept is given such that nuclear reaction model parameters together with their covariances can be derived in a least squares adjustment to the data.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Determination of the 338 eV, 1098 eV and 1370 eV s-wave resonance parameters for neutron induced reactions of 55Mn at GELINA

In this report new values for the resonance parameters of the 338 eV, 1098 eV and 1370 eV s-wave resonances of 55Mn are presented. The parameters were derived from a resonance shape analysis of transmission and capture data resulting from measurements at the time-of-flight facility GELINA. Special samples have been prepared to optimize the transmission at the resonance dips, to avoid the impact of sample inhomogeneities and to reduce bias effects due to multiple interaction events and the normalization of the capture data. The parameters have been adopted in an ENDF-6 compatible file which has been tested and implemented in the next release of the Joint Evaluated Fission and Fusion data library, i.e. JEFF-3.2, which is maintained by the Nuclear Energy Agency of the OECD.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Results of time-of-flight transmission measurements for 63,65Cu and natCu at a 50 m station of GELINA

Transmission measurements have been performed at the time-of-flight facility GELINA to determine neutron resonance parameters for 63Cu and 65Cu. The experiments have been carried out at a 50 m transmission station at a moderated neutron beam using a Li-glass scintillator with the accelerator operating at 800 Hz. Measurements were performed with a natCu metallic sample and metallic samples enriched in 63Cu and 65Cu. This report describes the experimental details required to deliver the experimental transmission to the EXFOR data library which is maintained by the Nuclear Energy Agency of the OECD and the Nuclear Data Section of the IAEA. The experimental conditions and data reduction procedures are described. In addition, the full covariance information based on the AGS concept is given, such that resonance parameters together with their covariances can be derived in a least squares adjustment to the data.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

JRC support to JAEA on the development of neutron resonance densitometry

The activities carried out during 2013 at the Institute for Reference Materials and Measurements of the Joint Research Centre of the European Commission to support the Japan Atomic Energy Agency in the development of Neutron Resonance Densitometry are described. These activities include experiments carried out at the time-of-flight facility GELINA, development of a model to account for sample inhomogeneities, assistance in data reduction and analysis procedures, preparation of test samples, training of JAEA staff and dissemination of the results.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Study of (n,xng) reactions on 238U

Prompt-gamma spectroscopy and time-of-flight techniques were used to measure (n,xn gamma) cross-sections on several nuclei of interest for nuclear reactors. Experiments were performed at the GELINA facility which provides a pulsed white neutron beam of maximum energy about 20 MeV. Preliminary results concerning 238U will be presented. This work was supported by PACEN/GEDEPEONand by the European Commission within the Sixth Framework Programme through I3-EFNUDAT (EURATOMcontract no. 036434) and NUDAME (Contract FP6-516487), and within the Seventh Framework Programme through EUFRAT (EURATOM contract no. FP7-211499) and through ANDES (EURATOM contract no. FP7-249671).JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

A New Setup for Neutron Inelastic Cross Section Measurements

An upgraded detection setup for neutron scattering measurements was recently completed at the GELINA neutron source of IRMM. A 200m flight path is used. Eight HPGe detectors are placed at 110° and 150° with respect to the neutron beam and are read-out by fast digitizers. The neutron flux is monitored by a 235U fission chamber. The first inelastic scattering measurement with the new setup was performed for natFe.JRC.D.5-Neutron physic

Gamma Production Cross Section Measurements for 76Ge via (n,n'gamma) at GELINA

This report describes the inelastic scattering data delivered to the Institute for Nuclear and Particle Physics of TU-Dresden. The GAINS setup was used for measurements of gamma production cross sections associated with the 69th excited state of 76Ge, using the (n, n'gamma) technique. The experimental work was performed at the GELINA facility at a 200 m flight path with eight high purity germanium detectors, using highly enriched 76Ge samples. A brief description of the experimental details and the results are presented.JRC.D.5-Nuclear physic

Target Requirements for Neutron-Induced Cross-Section Measurements in the Resonance Region

The influence of the target characteristics on the result of neutron induced cross section measurements is discussed. The basic principles of total and reaction cross section experiments are described. The discussion shows that each application requires targets with specific characteristics, such as the total number of nuclei per unit area, effective area and homogeneity, which have a strong impact on the total uncertainty of the quantities deduced from the measured data. Based on the measurement principles and on practical experience, recommendations for specific cross section measurements are presented. These recommendations refer to both the target properties and to the methods used for target characterization. In addition, a characterization method based on the use of neutron resonances is presented. This method can be used to determine the presence and quantity of contaminants and impurities which have a strong impact on the results of cross section measurements.JRC.DDG.D.5-Neutron physic

High resolution measurement of neutron inelastic scattering cross-sections for 23Na

The neutron inelastic scattering cross section of 23Na has been measured in response to the relevant request of the OECD-NEA High Priority Request List, which requires a target uncertainty of 4% in the energy range up to 1.35 MeV for the development of sodium fast-cooled reactors. The measurement was performed at the GELINA facility with the Gamma Array for Inelastic Neutron Scattering (GAINS), featuring eight high purity germanium detectors. The setup is installed at a 200 m flight path from the neutron source and provides high resolution measurements using the (n, n'g)- technique. The sample was an 80 mm diameter metallic sodium disk prepared at IRMM. Transitions up to the seventh excited state were observed and the differential gamma cross sections at 110º and 150º were measured, showing mostly isotropic gamma emission. From these the gamma production, level and inelastic cross sections were determined for neutrons energies up to 3837.5 keV. The results agree well with existing data and the evaluated nuclear data libraries in the low energies, and provide new experimental points in the little studied region above 2 MeV. Following a detailed review of the methodology used for the gamma efficiency calibrations and flux normalization of GAINS data, an estimated total uncertainty of 2.2 % was achieved for the inelastic cross section integrals over the energy ranges 0.498 -1.35 MeV and 1.35 - 2.23 MeV, meeting the required targets.JRC.D.4-Nuclear physic