1,408 research outputs found
New gas mixtures suitable for rare event detection using a Micromegas-TPC detector
The aim of the presented work was to develop further techniques based on a
Micromegas-TPC, in order to reach a high gas gain with good energy resolution,
and to search for gas mixtures suitable for rare event detection. This paper
focuses on xenon, which is convenient for the search of neutrinoless double
beta decay in 136 Xe. Conversely, a small admixture of xenon to CF 4 can reduce
attachment in the latter. This gas mixture would be suitable for dark matter
searches and the study of solar and reactor neutrinos. Various configurations
of the Micromegas plane were investigated and are described.Comment: 14 pages, 8 figures, article, revised version with improved figures,
text modifications, accepted for publication by JINS
Determination of Strong-Interaction Widths and Shifts of Pionic X-Rays with a Crystal Spectrometer
Pionic 3d-2p atomic transitions in F, Na, and Mg have been studied using a bent crystal spectrometer. The pionic atoms were formed in the production target placed in the external proton beam of the Space Radiation Effects Laboratory synchrocyclotron. The observed energies and widths of the transitions are E=41679(3) eV and Γ=21(8) eV, E=62434(18) eV and Γ=22(80) eV, E=74389(9) eV and Γ=67(35) eV, in F, Na, and Mg, respectively. The results are compared with calculations based on a pion-nucleus optical potential
Investigations of fast neutron production by 190 GeV/c muon interactions on different targets
The production of fast neutrons (1 MeV - 1 GeV) in high energy muon-nucleus
interactions is poorly understood, yet it is fundamental to the understanding
of the background in many underground experiments. The aim of the present
experiment (CERN NA55) was to measure spallation neutrons produced by 190 GeV/c
muons scattering on carbon, copper and lead targets. We have investigated the
energy spectrum and angular distribution of spallation neutrons, and we report
the result of our measurement of the neutron production differential cross
section.Comment: 19 pages, 11 figures ep
Sub MeV Particles Detection and Identification in the MUNU detector ((1)ISN, IN2P3/CNRS-UJF, Grenoble, France, (2)Institut de Physique, Neuch\^atel, Switzerland, (3) INFN, Padova Italy, (4) Physik-Institut, Z\"{u}rich, Switzerland)
We report on the performance of a 1 m TPC filled with CF at 3
bar, immersed in liquid scintillator and viewed by photomultipliers. Particle
detection, event identification and localization achieved by measuring both the
current signal and the scintillation light are presented. Particular features
of particle detection are also discussed. Finally, the Mn
photopeak, reconstructed from the Compton scattering and recoil angle is shown.Comment: Latex, 19 pages, 20 figure
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Ground-based aerosol optical depth trends at three high-altitude sites in Switzerland and Southern Germany from 1995–2010
Ground-based aerosol optical depth (AOD) climatologies at three high-altitude sites in Switzerland (Jungfraujoch and Davos) and Southern Germany (Hohenpeissenberg) are updated and re-calibrated for the period 1995 – 2010. In addition, AOD time-series are augmented with previously unreported data, and are homogenized for the first time. Trend analysis revealed weak AOD trends (λ = 500 nm) at Jungfraujoch (JFJ; +0.007 decade-1), Davos (DAV; +0.002 decade-1) and Hohenpeissenberg
(HPB; -0.011 decade-1) where the JFJ and HPB trends were statistically significant at the 95% and 90% confidence levels. However, a linear trend for the JFJ 1995 – 2005 period was found to be more appropriate than for 1995 – 2010 due to the influence of stratospheric AOD which gave a trend -0.003 decade-1 (significant at 95% level). When correcting for a recently available stratospheric AOD time-series, accounting for Pinatubo (1991) and more recent volcanic eruptions, the
1995 – 2010 AOD trends decreased slightly at DAV and HPB but remained weak at +0.000 decade-1 and -0.013 decade-1 (significant at 95% level). The JFJ 1995 – 2005 AOD time-series similarly decreased to -0.003 decade-1 (significant at 95% level). We conclude that despite a more detailed re40
analysis of these three time-series, which have been extended by five years to the end of 2010, a significant decrease in AOD at these three high-altitude sites has still not been observed
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