Uncertainties of calculated coincidence-summing correction factors in gamma-ray spectrometry

Uncertainty propagation to the $\gamma$-$\gamma$ coincidence-summing correction factor from the covariances of the nuclear data and detection efficiencies have been formulated. The method was applied in the uncertainty analysis of the coincidence-summing correction factors in the $\gamma$-ray spectrometry of the $^{134}$Cs point source using a p-type coaxial HPGe detector.Comment: 4 pages, 2 figures, to be published in the proceedings of the "2019 International Conference on Nuclear Data for Science and Technology" (ND2019

High-resolution measurements of the exited states (n,pn), (n,dn) C-12 cross sections

Measurements of C12 cross sections for the excited states (n,p 0 ) up to (n,p 4 ) and (n,d 0 ), (n,d 1 ) have been carried out. The Van de Graaff neutron generator of the EC-JRC-IRMM laboratory has been used for these measurements. A very thin tritiated target (263 μg/cm 2 ) was employed with deuteron beams energies impinging on the target in the range 2.5–4.0 MeV. Neutrons in the range 18.9–20.7 MeV were produced with an intrinsic energy spread of 0.2–0.25% FWHM. With such narrow neutron energy spread, using a high energy resolution device such as a single crystal diamond detector, several peaks from the outgoing charged particles produced by the (n,p n ), (n,d n ) and also (n,α 0 ) reactions appear in the pulse height spectrum. The peaks can be identified using the reaction Q-values. The diamond detector used for these measurements has shown an intrinsic energy resolution lower than 0.9% FWHM. The analysis of the peaks has permitted to derive the partial carbon reaction cross sections for several excited states. The results are presented in this paper with the associated uncertainties and they are compared with different versions of TENDL compilation when these data are available (e.g. versions 2009, 2010, 2011 and 2015) and also with experimental results available in the EXFOR database

Measurement of the differential cross section of neutron scattering on deuterium in the neutron energy range from 400 keV to 2.5 MeV

The angular distribution of n-d scattering was investigated in the energy range from 400 keV to 2.5 MeV using the recoil detection method, irradiating a proportional counter filled with deuterated gases with monoenergetic neutrons. Several techniques were employed to minimise the contribution of photons to the pulse-height distributions. A dedicated Monte Carlo model was developed to determine the differential cross section that best reproduces the measurements. The results are compared with the theoretical calculation of Canton et al. and the ENDF/B-VII.1 evaluation

Fostering European Collaborations: EUFRAT and work done at the accelerator facilities of JRC-IRMM

The European Commission via the General Directorate RTD in its different Framework Programs supported collaborations of member state institutions dealing with nuclear data. The projects EFNUDAT, ERINDA, CHANDA and EUFRAT all have in common Transnational Access Activities (TAA) to partner institutions. Within the past 10 years the collaborations have grown and in CHANDA now 35 partners are involved of which 16 offer TAA to their facilities. Since June 2014 JRC-IRMM, one of the driving forces behind the TAA, launched its own TAA project EUFRAT to foster collaborations with member states institutions. The calls for proposals are open ended with a deadline twice a year. A Project Advisory Committee discusses the proposals and decides on about approval. Financial support is given to approved proposals for two scientists. So far two calls have been evaluated with a request for access totalling more than 5000 h. Examples of proposals at the accelerator facilities at the JRC-IRMM are presented showing the multitude of possibilities using the nuclear facilities at the JRC-IRMM

Encoded physics knowledge in checking codes for nuclear cross section libraries at Los Alamos

Checking procedures for processed nuclear data at Los Alamos are described. Both continuous energy and multi-group nuclear data are verified by locally developed checking codes which use basic physics knowledge and common-sense rules. A list of nuclear data problems which have been identified with help of these checking codes is also given

The 13

At nuclear fusion reactors, CVD diamond detectors are considered an advantageous solution for neutron flux monitoring. For such applications the knowledge of the cross section of neutron-induced nuclear reactions on natural carbon are of high importance. Especially the (n,α0) reactions, yielding the highest energy reaction products, are of relevance as they can be clearly distinguished in the spectrum. The 13C(n,α0)10Be cross section was measured relative to 12C(n,α0)9Be at the Van de Graaff facility of EC-JRC Geel, Belgium, at 14.3 MeV and 17.0 MeV neutron energies. The measurement was performed with an sCVD (single-crystal Chemical Vapor Deposition) diamond detector, where the detector material acted simultaneously as sample and as sensor. A novel data analysis technique, based on pulse-shape discrimination, allowed an efficient reduction of background events. The results of the measurement are presented and compared to previously published values for this cross-section

Viscosity and fission time scale of^{156}Dy

In the fusion-fission reaction Ar-40+Cd-116-->Dy-156-->fission, performed at beam energies E(b) = 216 MeV and 238 MeV, gamma rays were measured in coincidence with fission fragments. The gamma-ray spectra are interpreted using a modified version of the statistical-model code CASCADE. From a comparison of the experimental and calculated spectra it is deduced that the nuclear viscosity is in the range 0.01 <gamma <4. The extracted fission time scale is of the order of 10(-19) s