About time:Ageing influences neural markers of temporal predictability

Timing abilities help organizing the temporal structure of events but are known to change systematically with age. Yet, how the neuronal signature of temporal predictability changes across the age span remains unclear. Younger (n = 21; 23.1 years) and older adults (n = 21; 68.5 years) performed an auditory oddball task, consisting of isochronous and random sound sequences. Results confirm an altered P50 response in the older compared to younger participants. P50 amplitudes differed between the isochronous and random temporal structures in younger, and for P200 in the older group. These results suggest less efficient sensory gating in older adults in both isochronous and random auditory sequences. N100 amplitudes were more negative for deviant tones. P300 amplitudes were parietally enhanced in younger, but not in older adults. In younger participants, the P50 results confirm that this component marks temporal predictability, indicating sensitive gating of temporally regular sound sequences.</p

First Results of the 140^{140}Ce(n,γ)141^{141}Ce Cross-Section Measurement at n_TOF

An accurate measurement of the $^{140}$Ce(n,γ) energy-dependent cross-section was performed at the n_TOF facility at CERN. This cross-section is of great importance because it represents a bottleneck for the s-process nucleosynthesis and determines to a large extent the cerium abundance in stars. The measurement was motivated by the significant difference between the cerium abundance measured in globular clusters and the value predicted by theoretical stellar models. This discrepancy can be ascribed to an overestimation of the $^{140}$Ce capture cross-section due to a lack of accurate nuclear data. For this measurement, we used a sample of cerium oxide enriched in $^{140}$Ce to 99.4%. The experimental apparatus consisted of four deuterated benzene liquid scintillator detectors, which allowed us to overcome the difficulties present in the previous measurements, thanks to their very low neutron sensitivity. The accurate analysis of the p-wave resonances and the calculation of their average parameters are fundamental to improve the evaluation of the $^{140}$Ce Maxwellian-averaged cross-section

First Results of the 140^{140}Ce(n,γ)141^{141}Ce Cross-Section Measurement at n_TOF

An accurate measurement of the $^{140}$Ce(n,γ) energy-dependent cross-section was performed at the n_TOF facility at CERN. This cross-section is of great importance because it represents a bottleneck for the s-process nucleosynthesis and determines to a large extent the cerium abundance in stars. The measurement was motivated by the significant difference between the cerium abundance measured in globular clusters and the value predicted by theoretical stellar models. This discrepancy can be ascribed to an overestimation of the $^{140}$Ce capture cross-section due to a lack of accurate nuclear data. For this measurement, we used a sample of cerium oxide enriched in $^{140}$Ce to 99.4%. The experimental apparatus consisted of four deuterated benzene liquid scintillator detectors, which allowed us to overcome the difficulties present in the previous measurements, thanks to their very low neutron sensitivity. The accurate analysis of the p-wave resonances and the calculation of their average parameters are fundamental to improve the evaluation of the $^{140}$Ce Maxwellian-averaged cross-section

Study of the photon strength functions and level density in the gamma decay of the n+U-234 reaction

The accurate calculations of neutron-induced reaction cross sections are relevant for many nuclear applications. The photon strength functions and nuclear level densities are essential inputs for such calculations. These quantities for U-235 are studied using the measurement of the gamma de-excitation cascades in radiative capture on U-234 with the Total Absorption Calorimeter at n_TOF at CERN. This segmented 4 pi gamma calorimeter is designed to detect gamma rays emitted from the nucleus with high efficiency. This experiment provides information on gamma multiplicity and gamma spectra that can be compared with numerical simulations. The code DICEBOXC is used to simulate the gamma cascades while GEANT4 is used for the simulation of the interaction of these gammas with the TAC materials. Available models and their parameters are being tested using the present data. Some preliminary results of this ongoing study are presented and discussed

Measurement of the radiative capture cross section of the s-process branching points 204Tl and 171Tm at the n-TOF facility (CERN)

The neutron capture cross section of some unstable nuclei is especially relevant for s-process nucleosynthesis studies. This magnitude is crucial to determine the local abundance pattern, which can yield valuable information of the s-process stellar environment. In this work we describe the neutron capture (n,γ) measurement on two of these nuclei of interest, 204Tl and 171Tm, from target production to the final measurement, performed successfully at the n-TOF facility at CERN in 2014 and 2015. Preliminary results on the ongoing experimental data analysis will also be shown. These results include the first ever experimental observation of capture resonances for these two nuclei

Measurement of the 244^{244}Cm and 246^{246}Cm Neutron-Induced Cross Sections at the n_TOF Facility

The neutron capture reactions of the $^{244}$Cm and $^{246}$Cm isotopes open the path for the formation of heavier Cm isotopes and of heavier elements such as Bk and Cf in a nuclear reactor. In addition, both isotopes belong to the minor actinides with a large contribution to the decay heat and to the neutron emission in irradiated fuels proposed for the transmutation of nuclear waste and fast critical reactors. The available experimental data for both isotopes are very scarce. We measured the neutron capture cross section with isotopically enriched samples of $^{244}$Cm and $^{246}$Cm provided by JAEA. The measurement covers the range from 1 eV to 250 eV in the n_TOF Experimental Area 2 (EAR-2). In addition, a normalization measurement with the $^{244}$Cm sample was performed at Experimental Area 1 (EAR-1) with the Total Absorption Calorimeter (TAC)

LHC and HL-LHC: Present and future radiation environment in the high-luminosity collision points and RHA implications

The high-luminosity large hadron collider (HL-LHC) is a novel machine configuration which will rely on a number of key innovative technologies to enhance the performance of the present LHC machine as of 2025. The upgrade will also involve increased radiation levels that need to be predicted by combining scaled measurements and calculations in order to define the qualification requirements for electronic systems. In this paper, we describe such levels, first of all, by introducing the monitoring and calculation approaches used for the present LHC machine, and second, by applying scaling factors and dedicated simulations for the future HL-LHC accelerators. We present the levels according to the different areas relevant for the operation of electronics-based equipment, and discuss the associated radiation hardness assurance implications