  New experiment arrangement to study spin rotation and oscillation of
particles of gas target through which beam of high energy particles passes is
discussed. Such experiment arrangement make it realizable for storage ring and
allows to study zero-angle scattering amplitude at highest possible energies.
Life-time of particle beam in storage ring can reach several hours and even
days. Life-time of particle in gas target (gas trap) is long too. Particles
circulate in storage ring with frequency $\nu$ of several MHz that yields to
the $\nu$-fold increase of density of high energy particles beam blowing gas
trap in comparison with single passing case.
  Finally, this causes perfectly acceptable angle of spin rotation of particles
containing in gas cell. Relation between index of refraction and effective
potential energy of a particle in a medium is discussed. Phenomenon of spin
rotation of a particle captured to a trap under the action of a beam of
polarized particles is considered. Expressions for effective potential energy
and angle of spin rotation are derived for particles in a trap. Rrotation and
oscillation of deuteron spin is studied. Estimations for angle of rotation show
that the effect can be experimentally observed.
