Depolarization of a neutron beam in Laue diffraction by a noncentrosymmetric crystal

The depolarization of a neutron beam executing Laue diffraction in a thick (～3.5 cm) noncentrosymmetric α-quartz crystal is observed. This effect was predicted by us earlier and suggested for measuring the electric dipole moment (EDM) of a neutron. The effect is due to an interaction of the magnetic moment of a moving neutron with a strong crystal electric field, as a result of which the neutron spin rotates in opposite directions for waves of two types excited in the crystal. The effect is studied for neutron diffraction by a system of crystallographic (110) planes at Bragg angles close to π/2, up to 87°. It is shown that, for a crystal of thickness L=3.5 cm, a direct beam initially polarized along the reciprocal lattice vector becomes depolarized upon diffraction, irrespective of the value of Bragg angle, whereas the beam polarized perpendicular to the diffraction plane retains its polarization. The Eτ value determining the sensitivity of the method to EDM is experimentally estimated.     

Existence of Solutions for Steady Detonation of Gas Suspensions

The existence of solutions of the traveling–wave type is studied for a system of equations that describes a one–dimensional motion of a suspension of evaporating particles in a viscous and heat–conducting chemically reacting gas. Using topological methods, it is shown that solutions corresponding to weak, strong, and Chapman—Jouguet detonation exist under certain restrictions on energy release and mass transfer.