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

Fission cross section measurements for 240Pu, 242Pu

This report comprises the deliverable 1.5 of the ANDES project (EURATOM contract FP7-249671) of Task 3 "High accuracy measurements for fission" of Work Package 1 entitled "Measurements for advanced reactor systems". This deliverables provide evidence of a successful completion of the objectives of Task 3.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Application of Photon Strength Functions to (n,g ) Measurements with the n_TOF TAC

The neutron capture cross section measurements at the CERN n_TOF facility are performed using a new detection system, the segmented Total Absorption Calorimeter (TAC). All measurements are performed in reference to the well known 197Au s (n,g ). The accuracy of the measurements depends on the accuracy of the TAC detection efficiency, which is calculated by means of Monte Carlo simulations. In this MC simulation photon strength functions and level densities play a major role as ingredients used for the generation of primary events, that is the electromagnetic cascades following the (n,g ) process. We have calculated the TAC detection efficiency for the case of 197Au(n,g ) by adjusting the photon strength functions of 198Au so that the simulation reproduces the experimental data. Both the MC method and the uncertainty of the results are discussed.JRC.D.5-Neutron physic

Neutron Induced Reaction Cross Sections for the Radioactive Target Nucleus 99Tc

We present the first measured and interpreted excitation functions for three nuclear reactions on the radioactive target nucleus 99Tc over the energy range from threshold to 20.6 MeV. Excitation functions for the 99Tc(n,n'gamma)99mTc, 99Tc(n,p)99Mo, and 99Tc(n,alpha)96Nb reactions were measured using the activation method. High resolution gamma-ray spectroscopy was used requiring special attention to suppress Bremsstrahlung. The irradiated samples consisted of pressed pellets of metallic 99Tc in Al-capsules. Quasi mono-energetic neutrons were produced via the 3H(pn)3He, 2H(d,n)3He, and 3H(d,n)4He reactions. The neutron fluence was monitored via the well-known 115In(n,n')115mIn, 27Al(n,alpha)24Na, 27Al(n,p)27Mg, 56Fe(n,p)56Mn, and 93Nb(n,2n)92mNb standard reactions. Statistical model calculations incorporating precompound effects were performed for all the measured reaction channels using two different codes, namely TALYS and STAPRE. Good agreement was obtained for the reactions in which a charged particle was emitted and for the excitation of the isomer in inelastic scattering, above 5 MeV.JRC.D.5-Neutron physic

ARIEL & SANDA nuclear data activities

Nuclear data are fundamental quantities for developing nuclear energy concepts and research. They are essential for the simulation of nuclear systems, safety and performance calculations, and reactor instrumentation. Nuclear data improvement requires a combination of many different know-hows that are distributed over many institutions along Europe. In the EURATOM call for Nuclear Fission and Radiation Protection NFRP-2018, two nuclear data projects were started in September 2019: the Coordination and Support Action ARIEL (Accelerator and Research reactor Infrastructures for Education and Learning) and the Research and Innovation Action SANDA (Solving Challenges in Nuclear Data for the Safety of European Nuclear facilities). The ARIEL project integrates education and training of young scientists and technicians with access to neutron beam research infrastructures and supports scientific visits to conduct short-term research projects relevant to thesis works. The SANDA project is focuses on research innovation actions, including detector and nuclear target development, important nuclear data measurements, nuclear data evaluation, and validation. A description of these ongoing projects, including the first results, is the subject of this article

The Gamma Efficiency of the GAINS Spectrometer

The GAINS (Germanium Array for Inelastic Neutron Scattering) setup was recently installed at the GELINA (Geel Linear Accelerator) neutron source of EC-JRC-IRMM. In order to produce reliable neutron inelastic cross section data the setup requires a precise efficiency calibration for each sample under investigation. These samples represent extended sources in non-standard orientations and with significant self-attenuation of gamma rays. We present in detail the efficiency calibration procedure performed with two Monte Carlo simulations using MCNP and GEANT4. A good agreement is found between the two independent approaches. The general features of the simulations are discussed together with an in-depth description of the various factors influencing the efficiency.JRC.D.4-Nuclear physic

The response of single crystal diamond detectors to 17–34 MeV neutrons

The first measurements of the response of diamond detectors to neutrons in the energy range 17–34MeV are presented. The diamond detectors were irradiated with quasi-monoenergetic neutrons generatedthrough the 7Li(p,n)7Be reaction. The measured pulse-height spectra show specific peaks associated to neutroninduced reactions in carbon. The peak of the 12C(n,0)9Be was clearly separated from the rest of thespectra. The 12C(n,d0)11B and 12C(n,p0)12B peaks were clearly identified on a continuum originating fromthe breakup 12C(n,3) reaction, which dominates the low-energy part of the pulse-height spectra. The 12C(n,0)9Be, 12C(n,d0)11B and 12C(n,p0)12B cross sections that have never been measured in this high-energy rangebefore were determined. The measured data are compared with the European Activation File EAF-2010 libraryevaluated values.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

Neutron Activation Cross Sections on Lead Isotopes

The cross sections for the reactions 204Pb(n, n'gamma)204mPb, 204Pb(n, 2n)203Pb, 204Pb(n, 2n)203m1Pb, 204Pb(n, 3n)202mPb, 206Pb(n, 3n)204mPb, 206Pb(n,alpha)203Hg and 208Pb(n, p)208Tl were determined at the IRMM van de Graaff laboratory in the neutron energy range from 14 to 21 MeV. Both natural and enriched samples were irradiated with neutrons produced via the 3H(d,n)4He reaction. The induced activities were determined with gamma-ray spectrometry using a HPGe detector in a low-background shield. Neutron fluences were determined with the well-known cross section of the 27Al(n,alpha)24Na reaction. Enriched samples were essential to determine the cross sections for the reactions with 204mPb and 206mPb isomers in the final state. Accurate results for reactions with 204;206Pb as target nuclei with natural lead samples were enabled through a precise measurement of the isotopic ratios. For a first investigation of the consequences of the present data for nuclear reaction models they were confronted with calculations based on global parameter systematics in a phenomenological and in a microscopic approach and with parameters selected to reproduce the available experimental data. The TALYS code was used for the former two calculations involving parameter systematics while the STAPRE code was used for the latter calculation.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

High Resolution Neutron (n,xn) Cross-Section Measurements for 206;207;208Pb and 209Bi from Threshold up to 20 MeV

Gamma production cross sections for neutron inelastic scattering reactions (n,xn) (x = 1, 2, 3) were measured for three different highly enriched targets of 206Pb, 207Pb and 208Pb and for 209Bi. Using the known decay schemes of these isotopes, the total inelastic cross sections and level inelastic cross sections were determined. The measurements are continuous in neutron energy and cover a wide interval (from threshold energy up to about 20 MeV). The experiments were performed at the GELINA white neutron source, at the 200m flight path station with a time resolution of 8 ns, resulting in an unprecedented neutron energy resolution of 1.1 keV at 1MeV (36 keV at 10MeV).JRC.D.5-Neutron physic

Advanced metrology for new generation nuclear power plants

This EMRP (European Metrology Research Programme) project is looking at solving metrological problems related to a new generation of nuclear power plants. The proposed Generation IV power plants are designed to run safely, make efficient use of natural resources, minimize the waste and maintain proliferation resistance. In order to reach these goals, the reactor operation involves higher temperatures, high-energy neutron fluence, different types of fuel where the minor actinides are also used as fuel etc. In this multidisciplinary project, which has 12 partners in 10 countries, the work is focused on improved temperature measurements, investigation of thermal properties of advanced materials, determination of new and relevant nuclear data and development of measurement techniques for radionuclides suitable for Generation IV power plants.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard