16 research outputs found
Two-temperature relaxation and melting after absorption of femtosecond laser pulse
The theory and experiments concerned with the electron-ion thermal relaxation
and melting of overheated crystal lattice constitute the subject of this paper.
The physical model includes two-temperature equation of state, many-body
interatomic potential, the electron-ion energy exchange, electron thermal
conductivity, and optical properties of solid, liquid, and two phase
solid-liquid mixture. Two-temperature hydrodynamics and molecular dynamics
codes are used. An experimental setup with pump-probe technique is used to
follow evolution of an irradiated target with a short time step 100 fs between
the probe femtosecond laser pulses. Accuracy of measurements of reflection
coefficient and phase of reflected probe light are ~1% and \sim 1\un{nm},
respectively. It is found that,
{\it firstly}, the electron-electron collisions make a minor contribution to
a light absorbtion in solid Al at moderate intensities;
{\it secondly}, the phase shift of a reflected probe results from heating of
ion subsystem and kinetics of melting of Al crystal during 0
where is time delay between the pump and probe pulses measured from the
maximum of the pump;
{\it thirdly} the optical response of Au to a pump shows a marked contrast to
that of Al on account of excitation of \textit{d}-electronsComment: 6th International Conference on Photo-Excited Processes and
Applications 9-12 Sep 2008, Sapporo, Japan, http://www.icpepa6.com, the
contributed paper will be published in Applied Surface Science(2009
Nuclear emulsion with molybdenum filling for observation of decay
The usage of nuclear emulsion with molybdenum filling for observation of
decay are shown to be possible. Estimates for 1 kg of Mo
with zero background give the sensitivity for the decay of
Mo at the level of y for 1 year of measurement.Comment: 7 pages, 3 figure
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