Simple neutron scattering by a set of nuclei with spin zero

1 Simple neutron scattering by a set of nuclei with spin zero 

In this section, we shall study the simple scattering of neutron radiation by a sample containing a large number N of elementary centres / with zero spin. With 

To calculate the scattered flux, far from the target, we shall evaluate r for k0r 1. Let use the approximation 

We assumed that the atoms have fixed position vectors fj(J = 1. TV). In reality, in a macroscopic sample, these points have a time-dependent distribution (and at a given time, this distribution depends on the sample). In this case, the cross-section E(q) is an average over all the configurations of the system 

Let us consider the case where the bj (J = define the pair correlation function 

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