Impact Of Cross Section Uncertainties Research Articles

Understanding the energy resolution of liquid argon neutrino detectors

Available estimates for the energy resolution of DUNE vary by as much as a factor of four. To address this controversy, and to connect the resolution to the underlying physical processes, we build an independent simulation pipeline for neutrino events in liquid argon, combining the public tools GENIE and FLUKA. Using this pipeline, we first characterize the channels of non-hermeticity of DUNE, including subthreshold particles, charge recombination, and nuclear breakup. Particular attention is paid to the role of neutrons, which are responsible for a large fraction of missing energy in all channels. Next, we determine energy resolution, by quantifying event-to-event stochastic fluctuations in missing energy. This is done for several sets of assumptions about the reconstruction performance, including those available in the literature. The resulting migration matrices, connecting true and reconstructed neutrino energies, are presented. Finally, we quantify the impact of different improvements on the experimental performance. For example, we show that dropping particle identification information degrades the resolution by a factor of two, while omitting charge deposits from de-excitation gammas worsens it by about 25%. In the future, this framework can be used to assess the impact of cross section uncertainties on the oscillation sensitivity.

Revisiting the sensitivity studies for leptonic CP-violation and mass hierarchy with T2K, NOνA and LBNE experiments

Precision measurement of neutrino mixing parameters and the determination of mass hierarchy are the primary goals of present and upcoming neutrino experiments. In this work, we study the sensitivity of T2K, NOνA and LBNE experiments to discover leptonic charge parity (CP)-violation and the determination of neutrino mass hierarchy. We obtain the correlation between the CP-violating phase and the mixing angles , , and the sensitivity to determine the octant of atmospheric mixing angle . The entire analysis is performed for a total of ten years (5ν + 5 ) of the running of T2K, NOνA and LBNE experiments. Furthermore, we also consider the impact of cross section uncertainties on the CP-violation sensitivity of the LBNE experiment.

Sensitivity of Shallow Land Burial to neutron environment and activation cross sections in IFE thick-liquid concepts

A comprehensive assessment on the eligibility of reduced activation (RA) steels as structural chamber material in Inertial Fusion Energy (IFE) thick-liquid concepts is performed. As far as alloying elements, it is shown that the activation of tungsten is a question to debate. Regarding impurity elements, it is analyzed if they could question the possibility of obtaining real RA steels for shallow land burial (SLB). The effect of the thickness of the liquid wall on the SLB response of alloying and impurity elements is computed. And above all, we have estimated the impact of cross section uncertainties when addressing the former questions, and we identify those to be improved. The necessary improvement of some tungsten and niobium cross sections is justified.

An investigation of the activation of water by D-T fusion neutrons and some implications for fusion reactor technology

Several fundamental aspects of the activation of water by neutrons in D-T fusion systems have been investigated in this work. The basic physical principles involved and the status of pertinent nuclear cross-section and radioactivity data were reviewed. The integral response of the dominant 16O(n,p) 16N reaction was calculated using several evaluated differential cross-section representations and characteristic D-T fusion neutron spectra. The impact of cross-section uncertainties was also assessed in this context. Two integral experiments were carried out at a D-T neutron generator facility to investigate the production and transport of 16N radioactivity in a D-T fusion neutron environment. Radioactivity yield data were acquired in one of these integral experiments (IE-1) and the measured results were compared with values obtained from calculations which employed both analytical and Monte-Carlo techniques. Measurements on the shielding of high-energy gamma rays from 16N decay by stainless steel (SS-304) and copper were performed in an additional integral experiment (IE-2) and these data were interpreted by a combination of analytical calculations and Monte-Carlo simulation. Some consequences of neutron-induced 16N radioactivity in the cooling water of a fusion reactor were examined for two contemporary conceptual designs of the International Thermonuclear Experimental Reactor (ITER). This analysis benefitted from insight acquired through the present integral studies. It was found that this radioactivity generating process would lead to significant biological doses outside the reactor containment vessel and could also deliver potentially damaging radiation doses to superconducting magnet insulators unless care is taken to provide adequate shielding when designing a fusion reactor.

Impact of Cross-Section Uncertainties on the Nuclear Design of Hybrid Reactors

Cross-section uncertainty covariance matrices are generated and used with sensitivity coefficients to obtain estimates for the uncertainties in design parameters of a particular class of fission-fusion hybrid reactors, the SOLASE-H design. The analysis shows that the uncertainty in the /sup 233/U production ratio is about 4% and is due mostly to errors associated with the lead cross sections. Reducing the uncertainty in the Pb(n,2n'), Pb(n,3n'), and the Pb(n,nonelastic) cross sections, particularly in the energy range of 9 to 20 MeV, will significantly reduce this uncertainty. Improving the Th(n,..gamma..) cross section in the energy range of 0.35 to 3.35 keV can lead to a 40% reduction in the uncertainty in the /sup 233/U-breeding ratio. It is found that more accurate evaluation of the Pb(n,nonelastic) cross section in the energy range of 0.73 to 14 MeV can reduce the uncertainty in tritium breeding from /sup 6/Li by about 25%. The uncertainty of only 1% found in the tritium-breeding ratio from /sup 7/Li indicates that present nuclear data uncertainties are adequately small. Uncertainty in displacements per atom in Zircaloy-2 cladding due to uncertainties in the Pb(n,inelastic) cross section is small. The analysis reveals the importance of reducing uncertainties in the Th(n,fission) cross sectionsmore » to minimize the uncertainty in the heating rate from nuclear reactions. It is found that uncertainties in the /sup 6/Li(n,..cap alpha..) cross section are acceptable in calculating the various nuclear parameters of the SOLASE-H design.« less