35 research outputs found
Mobility of thorium ions in liquid xenon
We present a measurement of the Th ion mobility in LXe at 163.0 K and
0.9 bar. The result obtained, 0.2400.011 (stat) 0.011 (syst)
cm/(kV-s), is compared with a popular model of ion transport.Comment: 6.5 pages,
Systematic study of trace radioactive impurities in candidate construction materials for EXO-200
The Enriched Xenon Observatory (EXO) will search for double beta decays of
136Xe. We report the results of a systematic study of trace concentrations of
radioactive impurities in a wide range of raw materials and finished parts
considered for use in the construction of EXO-200, the first stage of the EXO
experimental program. Analysis techniques employed, and described here, include
direct gamma counting, alpha counting, neutron activation analysis, and
high-sensitivity mass spectrometry.Comment: 32 pages, 6 figures. Expanded introduction, added missing table
entry. Accepted for publication in Nucl. Instrum. Meth.
Recent advances in neutrinoless double beta decay search
Even after the discovery of neutrino flavour oscillations, based on data from
atmospheric, solar, reactor, and accelerator experiments, many characteristics
of the neutrino remain unknown. Only the neutrino square-mass differences and
the mixing angle values have been estimated, while the value of each mass
eigenstate still hasn't. Its nature (massive Majorana or Dirac particle) is
still escaping. Neutrinoless double beta decay (-DBD) experimental
discovery could be the ultimate answer to some delicate questions of elementary
particle and nuclear physics. The Majorana description of neutrinos allows the
-DBD process, and consequently either a mass value could be measured or
the existence of physics beyond the standard should be confirmed without any
doubt. As expected, the -DBD measurement is a very difficult field of
application for experimentalists. In this paper, after a short summary of the
latest results in neutrino physics, the experimental status, the R&D projects,
and perspectives in -DBD sector are reviewed.Comment: 36 pages, 7 figures, To be publish in Czech Journal of Physic
Body temperature responses of Great Tits Parus major to handling in the cold
Animals typically respond to stressful stimuli such as handling by increasing core body temperature. However, small birds in cold environments have been found to decrease body temperature (Tb) when handled over longer periods, although there are no data extending beyond the actual handling event in such birds. We therefore measured both the initial Tb decrease during ringing and standardized Tb sampling, and subsequent recovery of Tb after this handling protocol in wild Great Tits Parus major roosting in nestboxes in winter. Birds reduced their Tb by 2.3 °C during c. 4 min of handling. When birds were returned to their nestboxes after handling, Tb decreased by a further 1.9 °C over c. 2 min, reaching a Tb of 34.6 °C before taking 20 min to rewarm to 2.5 °C above their initial Tb. The Tb reduction during handling could be a consequence of increased heat loss rate from disrupted plumage insulation, whereas Tb reduction after handling might reflect reduced heat production. These are important factors to consider when handling small birds in the cold