An Introduction to Neutron Scattering - Spallation Neutron Source

What Is the Neutron Wavevector Inside a Medium?
[ ]
materials.
most
from
reflected
externally
are
neutrons
1,
n
generally
Since
2
/
1
:
get
we
)
A
10
(~
small
very
is
and
),
definition
(by
index
refractive
Since
material
a
in
r
wavevecto
the
is
and
vevector
neutron wa
is
where
4
/
)
(
2
Simlarly
.
/
2
so
)
(
0
)
(
/
)
(
2
:
equation
s
r'
Schrodinge
obeys
neutron
The
(SLD)
Density
Length
Scattering
nuclear
the
called
is
1
where
2
:
is
medium
the
inside
potential
average
the
So
nucleus.
single
a
for
)
(
2
)
(
:
by
given
is
potential
neutron
-
nucleus
the
Rule,
Golden
s
Fermi'
by
given
with that
S(Q)
for
expression
our
Comparing
2
2
-
6
-
0
0
2
0
2
2
2
2
0
.
2
2
2
2
<
=
=
=
−
=
−
=
=
=
=
−
+
∇
=
=
=
∑
π
ρ
λ
ρ
πρ
ψ
ψ
ρ
ρ
ρ
π
δ
π
-
n
n
k/k
k
in vacuo
k
k
V
E
m
k
mE
k
e
r
in vacuo
r
V
E
m
b
volume
m
V
r
b
m
r
V
r
k
i
i
i
o h
h
h
h
r
h
r
r
r