Nuclear-Atomic Processes Department
(Head – Prof. A. I. Levon)
Created in 1989 on the base of the
laboratory of nuclear moments.
Main directions of scientific activity:
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Experimental investigations of
the static magnetic dipole and electric quadrupole moments of excited nuclei
and study of the probabilities of electro-magnetic transitions.
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On-line
g-spectroscopy
on the beams of the charged particles and heavy ions.
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Nuclear spectroscopy in the
transfer reactions.
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Development of the methods of
nuclear microanalysis. Extension of their analytical possibilities by using
the orientation effects in the crystalline materials.
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Radiospectroscopic research of
the radiation damages in the crystalline organic compounds.
The most important scientific results:
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Method of the perturbed
differential angular distribution of
g-rays
on pulsed beam is developed for the measurement of the magnetic dipole and
electric quadrupole moments of excited nuclei.
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Measurements of the magnetic
and electric moments of the excited states are carried out for more then 50
nuclei with the aim to study their structure.
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Anomaly of the orbital
magnetism of nucleons inside of the nuclei in comparison with free nucleons
was established and studied.
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Theory of magnetic moments
based on the quasiparticle-phonon model is suggested, which successively
takes into account the effects of the spin polarization of core, collective
effects and effects of the operator modification.
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Complex study of violation of
the reflection symmetry in the nuclei of 229Pa and 231Pa
was carried out. Collective parity-doublet bands were observed with
properties typical for reflection symmetry. Explanation of these properties
was suggested as a mutual mixing of the Nilsson states in the combination
with the octupole phonons.
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Confirmation of the theory of
supersymmetry is obtained, which considers the boson and fermion degries of
freedom in unique approach. Study of the supersymmetry phenomena is carried
out for the quartet of nuclei: even-even 194Pt, odd 195Pt
and 195Au and odd-odd 196Au.
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Elastic resonance scattering of
ions as nuclear analytical method has been elaborated. The following
possibilities of their use are experimentally substantiated and verified:
wide resonances in the scattering with large difference interference on a
matrix, polarization effect in the scattering on the matrix nuclei, wide
resonance in the scattering on the impurity nuclei, wide resonance and
polarization effect in the scattering on matrix nuclei in combination with
channeling. In case of the use of narrow resonances the necessity for
correct account of their form is grounded and confirmed experimentally.
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Electron and three-dimensional
structure of the radiation damages in the aminoacid crystals is established
as well as mechanism of their internal movement and manifestation of these
effects in the ESR spectra.