An Introduction to Neutron Scattering - Spallation Neutron Source

The Underlying Physics of Neutron Spin Echo (NSE)
Technology is Larmor Precession of the Neutron’s Spin
• The time evolution of the expectation value of the spin of a
spin-1/2 particle in a magnetic field can be B
determined classically as:
r
ds
r r
= γs
∧ B ⇒ ω L
dt
= γ B
s
−1
−1
γ = −2913
* 2π
Gauss . s
• The total precession angle of the spin, φ, depends on the time
the neutron spends in the field: φ = ω t
B(Gauss)
10
ω L (10 3 rad.s -1 )
183
L
N (msec -1 )
29
Turns/m for
4 Å neutrons
~29