- Saturation

Saturation

Previously, we considered the interaction between the spins and lattice and found the characteristic relaxation time $T_{1}$. That is, when the spin temperature $T_{_{S}}$ is greater than the lattice temperature $T$ how long does it take for the spin temperature to return to the lattice temperature? Answer: $T_{1}$.

We then discussed spin-spin interactions which led to the notion of inhomogeneous broadening by a spatially-varying local magnetic field. This led to the concept of a phase-memory time constant $T_{2}$. That is, when two nearly-resonant spins are excited then allowed to freely decay (RF field off) how long before the two spins are out of phase? Answer: $T_{2}$.

We now investigate the steady-state behavior of the spin-lattice system with an applied transverse RF field.