Equation (28) describes a Larmor precession whose frequency is following the time dependence of the magnetic field (note that [[omega].sub.L] is defined as the Larmor frequency
at H = [H.sub.0], so that [[omega].sub.L] cos(tot) gives the Larmor frequency
at H = H(t)).
from the nominal Larmor frequency
or the effects of static field
The Larmor frequency
is the frequency at which energy can be absorbed by the atomic nucleus and is the RF frequency driving the [B.sub.1] coils.
The goal of the RF front end on the transmit side is to transform the low voltage signal at the Larmor frequency
with the appropriate envelope as generated in the spectrometer into a powerful pulse of RF energy which is efficiently delivered to the RF coil in quadrature without damaging the sensitive receive electronics.
The resonant working frequency of our MM lens is designed to be 63.58 MHz, which corresponds to the Larmor frequency
of the 1.5 T MRI system.
When a molecule containing these atoms is placed in a magnetic field, the spins act as tiny magnetic dipoles, which align with the magnetic field and precess about its axis with a characteristic frequency called the Larmor frequency
. The exact frequency is very sensitive to the molecular environment in which the spins reside, as well as to the presence of other spins in the molecule.
When the variation of the magnetic field is slow compared to the Larmor frequency
, the spin will follow the direction of the magnetic field.
However, they showed that for increasing [B.sub.0]/[B.sub.rf], the solution increasingly approximates to that of a "static + circular" field with a similarly-shaped resonance curve, but with a resonance frequency that deviates from the classical Larmor frequency
, [[omega].sub.0], by a fractional amount equal to
A circularly polarized laser light transmitted through a glass cell containing a vapor of alkali atoms (e.g., Cs) resonates when its frequency equals the first absorption line of the alkali atoms, thus creating a spin alignment that precesses with a frequency proportional to the modulus of an externally applied magnetic field, [B.sub.0] (Larmor frequency
, [w.sub.L] = [gamma][absolute value of [B.sub.0]]).
The neutron Larmor frequency
is 15 kHz at 0.5 mT, therefore, the variation of the rf phase in the neutron pulse becomes