A pulsed field gradient is a short, timed pulse with spatial-dependent field intensity. Any gradient is identified by four characteristics: axis, strength, shape and duration. Pulsed field gradient (PFG) techniques are key to

magnetic resonance imaging Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and ...

, spatially selective spectroscopy and studies of

diffusion Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical p ...

via diffusion ordered

nuclear magnetic resonance spectroscopy Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy or magnetic resonance spectroscopy (MRS), is a Spectroscopy, spectroscopic technique based on re-orientation of Atomic nucleus, atomic nuclei with non-zero nuclear sp ...

(DOSY). PFG techniques are widely used as an alternative to phase cycling in modern NMR spectroscopy.

Common field gradients in NMR

The effect of a uniform magnetic field gradient in the z-direction on spin I, is considered to be a rotation around z-axis by an angle = γ_IGz; where Gz is the gradient magnitude (along the z-direction) and γ_I is the

gyromagnetic ratio In physics, the gyromagnetic ratio (also sometimes known as the magnetogyric ratio in other disciplines) of a particle or system is the ratio of its magnetic moment to its angular momentum, and it is often denoted by the symbol , gamma. Its SI u ...

of spin I. It introduces a phase factor to the magnetizations: ''Φ (z,τ) = (γ_I)(Gz)(τ)'' The time duration τ is in the order of milliseconds.

References

Nuclear magnetic resonance {{NMR-stub

Common field gradients in NMR

See also

References