1,442 research outputs found
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 Î=21(8) eV, E=62434(18) eV and Î=22(80) eV, E=74389(9) eV and Î=67(35) eV, in F, Na, and Mg, respectively. The results are compared with calculations based on a pion-nucleus optical potential
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
Low energy tracking and particles identification in the MUNU Time Projection Chamber at 1 bar. Possible application in low energy solar neutrino spectroscopy
In this paper we present the results from the measurements made with the MUNU
TPC at 1bar pressure of CF4 in the energy region below 1 MeV. Electron events
down to 80 keV are successfully measured. The electron energy and direction are
reconstructed for every contained single electron above 200 keV. As test the
137Cs photopeak is reconstructed by measuring both the energy and direction of
the Compton electrons in the TPC.Comment: 19 pages, 9 figures (6 figures in color); Figure 10 has been deleted
from [v1]. Additional paragraph has been included; Manuscript is submitted to
Nuclear Inst. and Methods in Physics Research,
Recommended from our members
Ground-based aerosol optical depth trends at three high-altitude sites in Switzerland and Southern Germany from 1995â2010
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 â 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 â 2005 period was found to be more appropriate than for 1995 â 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 â 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 â 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
Observation of single collisionally cooled trapped ions in a buffer gas
Individual Ba ions are trapped in a gas-filled linear ion trap and observed
with a high signal-to-noise ratio by resonance fluorescence. Single-ion storage
times of ~5 min (~1 min) are achieved using He (Ar) as a buffer gas at
pressures in the range 8e-5 - 4e-3 torr. Trap dynamics in buffer gases are
experimentally studied in the simple case of single ions. In particular, the
cooling effects of light gases such as He and Ar and the destabilizing
properties of heavier gases such as Xe are studied. A simple model is offered
to explain the observed phenomenology.Comment: 5 pages, 4 figures, accepted for publication in Phys. Rev. A. Minor
text and figure change
Limits on the neutrino magnetic moment from the MUNU experiment
The MUNU experiment was carried out at the Bugey nuclear power reactor. The
aim was the study of electron antineutrino-electron elastic scattering at low
energy. The recoil electrons were recorded in a gas time projection chamber,
immersed in a tank filled with liquid scintillator serving as veto detector,
suppressing in particular Compton electrons. The measured electron recoil
spectrum is presented. Upper limits on the neutrino magnetic moment were
derived and are discussed.Comment: 9 pages, 7 figures Added reference: p.3, 1st col., TEXONO Added
sentence: p.4, 1st col., electron attachement Modified sentence: p.5, 1st
col., readout sequence Added sentence: p.5, 1st col., fast rise time cu
A deficit of spatial remapping in constructional apraxia after right-hemisphere stroke
This Article is provided by the Brunel Open Access Publising Fund - Copyright @ 2010 Oxford University PressConstructional apraxia refers to the inability of patients to copy accurately drawings or three-dimensional constructions. It is a common disorder after right parietal stroke, often persisting after initial problems such as visuospatial neglect have resolved. However, there has been very little experimental investigation regarding mechanisms that might contribute to the syndrome. Here, we examined whether a key deficit might be failure to integrate visual information correctly from one fixation to the next. Specifically, we tested whether this deficit might concern remapping of spatial locations across saccades. Right-hemisphere stroke patients with constructional apraxia were compared to patients without constructional problems and neurologically healthy controls. Participants judged whether a pattern shifted position (spatial task) or changed in pattern (non-spatial task) across two saccades, compared to a control condition with an equivalent delay but without intervening eye movements. Patients with constructional apraxia were found to be significantly impaired in position judgements with intervening saccades, particularly when the first saccade of the sequence was to the right. The importance of these remapping deficits in constructional apraxia was confirmed through a highly significant correlation between saccade task performance and constructional impairment on standard neuropsychological tasks. A second study revealed that even single saccades to the right can impair constructional apraxia patientsâ perception of location shifts. These data are consistent with the view that rightward eye movements result in loss of remembered spatial information from previous fixations, presumably due to constructional apraxia patientsâ damage to the right-hemisphere regions involved in remapping locations across saccades. These findings provide the first evidence for a deficit in remapping visual information across saccades underlying right-hemisphere constructional apraxia.European Commission Marie Curie Intra-European Fellowship (011457 to C.R.) and a Wellcome Trust Senior Fellowship (to M.H.)
A magnetically-driven piston pump for ultra-clean applications
A magnetically driven piston pump for xenon gas recirculation is presented.
The pump is designed to satisfy extreme purity and containment requirements, as
is appropriate for the recirculation of isotopically enriched xenon through the
purification system and large liquid xenon TPC of EXO-200. The pump, using
sprung polymer gaskets, is capable of pumping more than 16 standard liters per
minute (SLPM) of xenon gas with 750 torr differential pressure.Comment: 6 pages, 5 figure
- âŠ