Encontrados 10 documentos, a visualizar página 1 de 1
Status and outlook of the neutron time-of-flight facility n_TOF at CERN
Gunsing, F.; Abbondanno, U.; Aerts, G.; Alvarez, H.; Álvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Assimakopoulos, P.; Audouin, L.The neutron time-of-flight facility n_TOF at CERN, fully operational since 2002, combines a high instantaneous neutron flux with high energy resolution. The wide energy range and the high neutron flux per time-of-flight burst result in a much enhanced signal to background ratio for neutron capture of radioactive isotopes and makes this facility well suited for the measurement of high quality neutron-induced rea...
Neutron reactions and nuclear cosmo-chronology
Mosconi, M.; Heil, M.; Käppeler, F.; Mengoni, A.; Plag, R.; Fujii, K.; Gallino, R.; Aerts, G.; Terlizzi, R.; Abbondanno, U.; Álvarez-Pol, H.The [beta]-decay of 187Re represents a suited cosmo-chronometer for the age of the r-process abundances, since the radiogenic part of the daughter isotope 187Os is defined by the difference between the solar 187Os abundance and s-process contribution to 187Os. The latter component can be determined via the s-process systematics based on the stellar neutron capture cross sections of 186Os and 187Os. The laborato...
Neutron capture cross section measurements for nuclear astrophysics at CERN n_TOF
Abbondanno, U.; Aerts, G.; Alvarez-Velarde, F.; Álvarez-Pol, H.; Andriamonje, S.; Andrzejewski, J.; Badurek, G.; Baumann, P.; Becvár, F.; Benlliure, J.A series of neutron capture cross section measurements of interest to nuclear astrophysics have been recently performed at n_TOF, the neutron spallation source operating at CERN. The low repetition frequency of the proton beam driver, the extremely high instantaneous neutron flux, and the low background conditions in the experimental area are optimal for capture cross section measurements on low-mass or radioac...
A low-mass neutron flux monitor for the n _TOF facility at CERN
Mastinu,P. F.; Abbondanno,U.; Aerts,G.; Alvarez,H.; Andriamonje,S.; Angelopoulos,A.; Assimakopoulos,P.; Bacri,C.O.; Badurek,G.; Baumann,P.; Becvár,F.A small-mass system has been developed for monitoring the flux of neutrons with energy up to 1 MeV at the new time-of-flight facility at CERN, n_TOF. The monitor is based on a thin Mylar foil with a 6Li deposit, placed in the neutron beam, and an array of Silicon detectors, placed outside the beam, for detecting the products of the 6Li(n, alpha)³H reaction. The small amount of material on the beam ensures a min...
Measurement of the n_TOF beam profile with a micromegas detector
Pancin, J.; Abbondanno, U.; Aerts, G.; Alvarez, H.; Andriamonje, S.; Angelopoulos, A.; Assimakopoulos, P.; Bacri, C.; Badurek, G.; Baumann, P.A Micromegas detector was used in the neutron Time-Of-Flight (n_TOF) facility at CERN to evaluate the spatial distribution of the neutron beam as a function of its kinetic energy. This was achieved over a large range of neutron energies by using two complementary processes: at low energy by capture of a neutron via the 6Li(n,[alpha])t reaction, and at high energy by elastic scattering of neutrons on gas nuclei ...
Physics at CPLEAR
Angelopoulos, A.; Apostolakis, A.; Aslanides, E.; Backenstoss, G.; Bargassa, P.; Bee, C. P.; Behnke, O.; Benelli, A.; Bertin, V.; Blanc, F.; Bloch, P.LEAR offered unique opportunities to study the symmetries which exist between matter and antimatter. At variance with other approaches at this facility, CPLEAR was an experiment devoted to the study of , and symmetries in the neutral-kaon system. A variety of measurements allowed us to determine with high precision the parameters which describe the time evolution of the neutral kaons and their antiparticles, in...
Measurement of the energy dependence of the form factor f+ in K0e3 decay
Apostolakis, A.; Aslanides, E.; Backenstoss, G.; Bargassa, P.; Behnke, O.; Benelli, A.; Bertin, V.; Blanc, F.; Bloch, P.; Carlson, P.; Carroll, M.Neutral-kaon decays to [pi]e[nu] were analysed to determine the q2 dependence of the K0e3 electroweak form factor f+. Based on 365 612 events, this form factor was found to have a linear dependence on q2 with a slope [lambda]+=0.0245±0.0012stat±0.0022syst. ; http://www.sciencedirect.com/science/article/B6TVN-414F7YB-Y/1/f9d5dd66c27d4f9264d1cec6fac93c68
Tests of the Equivalence Principle with neutral kaons
Apostolakis, A.; Aslanides, E.; Backenstoss, G.; Bargassa, P.; Behnke, O.; Benelli, A.; Bertin, V.; Blanc, F.; Bloch, P.; Carlson, P.; Carroll, M.We test the Principle of Equivalence for particles and antiparticles, using CPLEAR data on tagged K0 and decays into [pi]+[pi]-. For the first time, we search for possible annual, monthly and diurnal modulations of the observables [eta]+- and [phi]+-, that could be correlated with variations in astrophysical potentials. Within the accuracy of CPLEAR, the measured values of [eta]+- and [phi]+- are found not to b...
First direct observation of time-reversal non-invariance in the neutral-kaon sy...
Angelopoulos, A.; Apostolakis, A.; Aslanides, E.; Backenstoss, G.; Bargassa, P.; Behnke, O.; Benelli, A.; Bertin, V.; Blanc, F.; Bloch, P.; Carlson, P.We report on the first observation of time-reversal symmetry violation through a comparison of the probabilities of transforming into K0 and K0 into as a function of the neutral-kaon eigentime t. The comparison is based on the analysis of the neutral-kaon semileptonic decays recorded in the CPLEAR experiment. There, the strangeness of the neutral kaon at time t=0 was tagged by the kaon charge in the reaction at...
An EPR experiment testing the non-separability of the wave function
Apostolakis, A.; Aslanides, E.; Backenstoss, G.; Bargassa, P.; Behnke, O.; Benelli, A.; Bertin, V.; Blanc, F.; Bloch, P.; Carlson, P.; Carroll, M.The EPR-type strangeness correlation in the K0 system produced in the reaction at rest has been tested using the CPLEAR detector. The strangeness was tagged via strong interaction with absorbers away from the creation point. The results are consistent with the QM non-separability of the wave function and exclude a spontaneous wave-function factorisation at creation (CL >99.99%). ; http://www.sciencedirect.co...
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