Pulsed field gradient
 | This article needs additional citations for verification. (January 2017) |
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, spatially selective spectroscopy and studies of diffusion via diffusion ordered nuclear magnetic resonance spectroscopy (DOSY).[1][2] PFG techniques are widely used as an alternative to phase cycling in modern NMR spectroscopy.
Common field gradients in NMR
[edit | edit source]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 = γIGz; where Gz is the gradient magnitude (along the z-direction) and γI is the gyromagnetic ratio of spin I. It introduces a phase factor to the magnetizations:
Φ (z,τ) = (γI)(Gz)(τ)
The time duration τ is in the order of milliseconds.
See also
[edit | edit source]References
[edit | edit source]
.jpg){kind=small} | This nuclear magnetic resonance–related article is a stub. You can help Wikipedia by expanding it. |