Search results for "REEs"
showing 10 items of 921 documents
Unbiased sensitivity analysis and pruning techniques in neural networks for surface ozone modelling
2005
Abstract This paper presents the use of artificial neural networks (ANNs) for surface ozone modelling. Due to the usual non-linear nature of problems in ecology, the use of ANNs has proven to be a common practice in this field. Nevertheless, few efforts have been made to acquire knowledge about the problems by analysing the useful, but often complex, input–output mapping performed by these models. In fact, researchers are not only interested in accurate methods but also in understandable models. In the present paper, we propose a methodology to extract the governing rules of trained ANN which, in turn, yields simplified models by using unbiased sensitivity and pruning techniques. Our propos…
Beta Decay Studies of Neutron Rich Nuclei Using Total Absorption Gamma-ray Spectroscopy and Delayed Neutron Measurements
2010
International audience; A complete characterisation of the β-decay of neutron-rich nuclei can be obtained from the measurement of β-delayed gamma rays and, whenever the process is energetically possible, β-delayed neutrons. The accurate determination of the β-intensity distribution and the β-delayed neutron emission probability is of great relevance in the fields of reactor technology and nuclear astrophysics. A programme for combined measurements using the total absorption gamma-ray spectroscopy technique and both neutron counters and neutron time-of-flight spectrometers is presented.
Measurement of the atmospheric ?µ energy spectrum from 100 GeV to 200 TeV with the ANTARES telescope
2013
Atmospheric neutrinos are produced during cascades initiated by the interaction of primary cosmic rays with air nuclei. In this paper, a measurement of the atmospheric energy spectrum in the energy range 0.1-200 TeV is presented, using data collected by the ANTARES underwater neutrino telescope from 2008 to 2011. Overall, the measured flux is similar to 25 % higher than predicted by the conventional neutrino flux, and compatible with the measurements reported in ice. The flux is compatible with a single power-law dependence with spectral index gamma (meas)=3.58 +/- 0.12. With the present statistics the contribution of prompt neutrinos cannot be established.
The BRIKEN Project: Extensive Measurements of $\beta $-delayed Neutron Emitters for the Astrophysical r Process
2018
An ambitious program to measure decay properties, primarily β-delayed neutron emission probabilities and half-lives, for a significant number of nuclei near or on the path of the rapid neutron capture process, has been launched at the RIKEN Nishina Center. We give here an overview of the status of the project.
Commissioning of the BRIKEN beta-delayed neutron detector for the study of exotic neutron-rich nuclei
2017
Beta-delayed neutron emission (Beta-n) is a form of radioactive decay in which an electron, an anti-neutrino and one or more neutrons are emitted. This process arises if the energy window of the decay Q_Beta is greater than the neutron separation energy S n of the daughter. The probability in each decay of emitting neutrons is called the Pn value. This form of decay plays a key role in the synthesis of chemical elements in the Universe via the rapid neutron capture process, or r-process. The r-process proceeds far from the valley of nuclear stability, and leads to very neutron-rich nuclei that then decay to the line of stability. Most of these nuclei are ßn emitters. The initial abundance d…
A search for neutrino emission from the Fermi bubbles with the ANTARES telescope
2014
Adrián-Martínez, S. et al.
Searches for clustering in the time integrated skymap of the ANTARES neutrino telescope
2014
Adrián-Martínez, S. et al.
ANTARES constrains a blazar origin of two IceCube PeV neutrino events
2015
Abstract Context. The source(s) of the neutrino excess reported by the IceCube Collaboration is unknown. The TANAMI Collaboration recently reported on the multiwavelength emission of six bright, variable blazars which are positionally coincident with two of the most energetic IceCube events. Objects like these are prime candidates to be the source of the highest-energy cosmic rays, and thus of associated neutrino emission. Aims. We present an analysis of neutrino emission from the six blazars using observations with the ANTARES neutrino telescope. Methods. The standard methods of the ANTARES candidate list search are applied to six years of data to search for an excess of muons and hence th…
Search for Multimessenger Sources of Gravitational Waves and High-energy Neutrinos with Advanced LIGO during Its First Observing Run, ANTARES, and Ic…
2019
[EN] Astrophysical sources of gravitational waves, such as binary neutron star and black hole mergers or core-collapse supernovae, can drive relativistic outflows, giving rise to non-thermal high-energy emission. High-energy neutrinos are signatures of such outflows. The detection of gravitational waves and high-energy neutrinos from common sources could help establish the connection between the dynamics of the progenitor and the properties of the out¿ow. We searched for associated emission of gravitational waves and high-energy neutrinos from astrophysical transients with minimal assumptions using data from Advanced LIGO from its first observing run O1, and data from the ANTARES and IceCub…
7Be(n,α) and 7Be(n,p) cross-section measurement for the cosmological lithium problem at the n-TOF facility at CERN
2017
One of the most puzzling problems in Nuclear Astrophysics is the “Cosmological Lithium Problem”, i.e the discrepancy between the primordial abundance of \(^{7}\)Li observed in metal poor halo stars (Asplund et al. in Astrophys J 644:229–259, 2006, [1]), and the one predicted by Big Bang Nucleosynthesis (BBN). One of the reactions that could have an impact on the problem is \(^{7}\)Be(n,p)\(^{7}\)Li. Despite of the importance of this reaction in BBN, the cross-section has never been directly measured at the energies of interest for BBN. Taking advantage of the innovative features of the second experimental area at the n\(\_\)TOF facility at CERN (Sabate-Gilarte et al. in Eur Phys J A 53:210,…