As discussed above, for the effective elastic scattering, the scattering angles
are modest and the scattered particles tend to hit the detector, so FFD is not required.
In SANS, a beam of neutrons is focused on a sample and the neutrons that are scattered at small scattering angles
are detected on a two-dimensional (2D) detector.
The matter is that the structure of the collision integral implies division of its kernel onto three parts related to hard (hard collisions are mainly large-angle scattering collisions  that lead to establishing the equilibrium distribution of molecules over velocities after each collision, soft collisions are caused by classical scattering on small angles less 0.3 rad , and the diffraction-scattering collisions occur when scattering angles
are ~0.01 rad [8-10].), soft, and diffraction-scattering collisions [7-11].
The scattering angles
work with [theta] varies from 0[degrees] to 360[degrees] and [phi] = 0[degrees].
Bistatic scattering patterns for the scattering coefficient y (magnitude) as a function of the scattering angles
[[theta].sub.2] and [[theta].sub.3] of Fig.
The incident and scattering angles
are set by [[theta].sub.s] = [[theta].sub.i], [[phi].sub.s] = [[phi].sub.i] = 90[degrees].
For bistatic case, the average NRCS versus scattering angles
for incidence angles of 0[degrees] and 45[degrees] are shown in Figure 4.
For scattering angles
below [approximately equal to]17[degrees] the analyzer system moves behind the beam stop.
To ascertain the validity of Guinier's approximation to the EVA nanocomposites, it is imperative that two conditions be satisfied: (a) There is a linear fit between In [I(q)] and [q.sup.2] at low q, corresponding to small scattering angles
; (b) q[R.sub.g] < 1.
Figure 1 presents the optical geometry, where [[theta].sub.o] and [[theta].sub.s] are the incidence and scattering angles
measured with respect to the normal of the specimen.
With essentially 1.3 million detector elements collecting light scattering data for each of several exposures as it steps through the range of scattering angles
, the instrument delivers unprecedented detail required for serious research projects.