Reports From National Academy Of Science Republ Armenia Add New Data

REPORTS FROM NATIONAL ACADEMY OF SCIENCE REPUBL ARMENIA ADD NEW DATA TO RESEARCH IN NUCLEAR PHYSICS

Physics Week
July 27, 2010

According to recent research from Yerevan, Armenia, “The diffraction of
neutrons is considered in crystals under the influence of a standing
sound wave. The scattering probability is calculated for the elastic
neutron-crystal interaction, whereas the neutron-standing sound wave
interaction can be either elastic and inelastic.”

“The possibility of short-wave (high-energy) neutrons diffraction is
illustrated. It is shown that the Debye-Waller factor can be changed
and tuned. The analysis of conservation laws are adduced both for
thermal and short-wave neutrons. The formation of a “sublattice” is
shown in the process of neutrons elastic diffraction with respect
to standing sound wave. The analogous to the Kapitza-Dirac effect
is considered for neutrons,” wrote K.K. Grigoryan and colleagues,
National Academy of Science Republ Armenia.

The researchers concluded: “The problem is solved within the frame of
non-stationary S-matrix theory, where the neutron-phonon interaction
is described by the Fermi pseudopotential, which is considered as
a perturbation.”

Grigoryan and colleagues published their study in Nuclear Instruments
& Methods in Physics Research Section B – Beam Interactions with
Materials and Atoms (On the neutron diffraction in crystals in the
field of a standing sound wave. Nuclear Instruments & Methods in
Physics Research Section B – Beam Interactions with Materials and
Atoms, 2010;268(14):2366-2370).

For additional information, contact A.G. Hayrapetyan, National
Academy Science Republ Armenia, Institute Applied Problems Physics,
25 Hr Nersisyan Str, Yerevan 0014, Armenia.

Publisher contact information for the journal Nuclear Instruments
& Methods in Physics Research Section B – Beam Interactions with
Materials and Atoms is: Elsevier Science BV, PO Box 211, 1000 AE
Amsterdam, Netherlands.

From: A. Papazian