Small-Angle Neutron Scattering - Kfki

Polydisperse systems. General case
I(q) = + +
is averaging over the particle polydispersity function.
The idea of the following transformations is to introduce the effective mean
scattering length density, ρ e , independent of the averaging, so that the
intensity equation takes the classical form but with the modified contrast.
∆ ~ ρ =
ρ e
− ρ s
Mitglied in der Helmholtz-Gemeinschaft
∆ ρ ρ − ρ + ρ − ρ = ρ − ρ + ∆
~ ρ
I(
q)
=
=
e e s
e
~
I
s
( q)
+ ∆
~~
ρI
cs
( q)
+
( ∆
~ ρ)
2
~
I
c
( q)