19 research outputs found
Angular analysis of bremsstrahlung in alpha decay
A new quantum electrodynamical method of calculations of bremsstrahlung
spectra in the -decay of heavy nuclei taking into account the angle
between the directions of -particle motion (or its tunneling) and
photon emission is presented. The angular bremsstrahlung spectra for
have been obtained for the first time. According to calculations,
the bremsstrahlung in the -decay of this nucleus depends extremely
weakly on the angle. Taking into account nuclear forces, such dependence is not
changed visibly. An analytical formula of the angular dependence of the
bremsstrahlung spectra is proposed and gives its harmonic behavior. The
extremal values of the angle, at which the bremsstrahlung has maximal and
minimal values, has been found.Comment: 15 pages, 1 file of figure in EPS format, LaTeX v.2e with EPJ style.
In the new variant of the paper: 1) more attention is given to a convergence
problem of computer calculations of the bremsstrahlung spectra; 2) a new
section with inclusion of Woods-Saxon component in construction of the total
realistic -nucleus potential into our model (with our first
brermsstrahlung spectra for at such potential) is included into
the paper; 3) possible ways of further improvement of the quantum-mechanical
models are pointed ou
Evaporation and Condensation of Clusters
Influence of surrounding matter on the properties of clusters is considered
by an approach combining the methods of statistical and quantum mechanics. A
cluster is treated as a bound N-particle system and surrounding matter as
thermostat. It is shown that, despite arbitrary strong interactions between
particles, cluster energy can be calculated by using the controlled
perturbation theory. The accuracy of the latter is found to be much higher than
that of the quasiclassical approximation. Spectral distribution is obtained by
minimizing conditional entropy. Increasing the thermostat temperature leads to
the depletion of bound states. The characteristic temperature when bound states
become essentially depleated defines the temperature of cluster evaporation.
The inverse process of lowering the thermostate temperature, yielding the
filling of bound states, corresponds to cluster condensation.Comment: 1 file, 15 pages, RevTex, 4 table
Bremsstrahlung emission during -decay of
We obtained the spectrum of probability of the bremsstrahlung emission
accompanying the -decay of (E=4.8 MeV) by
measuring the - coincidences and using the model presented in
our previous study on the decay of (E=7.7
MeV). We compare the experimental data with the quantum mechanical calculation
and find a good agreement between theory and experiment. We discuss the
differences between the photon spectra connected with the -decay of the
and nuclei. For the two mentioned nuclei we
analyze the bremsstrahlung emission contributions from the tunneling and
external regions of the nucleus barrier into the total spectrum, and we find
the destructive interference between these contributions. We also find that the
emission of photons during tunneling of the -particle gives an
important contribution to the bremsstrahlung spectrum in the whole E
energy range of the studied Ra nucleus
Multipolar model of bremsstrahlung accompanying proton-decay of nuclei
Emission of bremsstrahlung photons accompanying proton decay of nuclei is
studied. The new improved multipolar model describing such a process is
presented. The angular formalism of calculations of the matrix elements is
stated in details. The bremsstrahlung probabilities for the ,
, and nuclei decaying from
the state, the and nuclei decaying from the state, the and nuclei decaying from the
state are predicted. Such spectra have orders of values similar to the
experimental data for the bremsstrahlung photons emitted during the
-decay. This indicates on real possibility to study bremsstrahlung
photons during proton decay experimentally and perform further measurements.Comment: 14 pages, 6 figure
Search for P-odd time reversal noninvariance in nuclear processes
The scheme of search for time reversal noninvariance in nuclear processes based on the measurement of linear polarization of gamma radiation of a sample aligned by a preceding nuclear decay or by cryogenic means is presented