Nuclei With Non-Zero Spin Align in Magnetic Fields

1
Nuclei With Non-Zero SpinAlign in Magnetic Fields
Ho
Alignment
Energy
parallel
anti-parallel
2
Resonance Perturb Equilibrium
Ho
3
Return to Equilibrium (Relax) Read Out Signals
4
Magnetic Resonance Sensitivity
DE is small At room temp., DN
1105 Intrinsically low sensitivity? Need lots of
sample
Increase sensitivity by increasing magnetic field
strength
5
Intrinsic Sensitivity of Nuclei
Nucleus g Natural Relative
Abundance Sensitivity 1H 2.7 x 108
99.98 1.0 13C 6.7 x 107
1.11 0.004 15N -2.7 x 107
0.36 0.0004 31P 1.1 x 108
100. 0.5