# Difference between revisions of "Grad pulse.m"

From Spinach Documentation Wiki

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rho - spin system state vector | rho - spin system state vector | ||

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L - system Liouvillian | L - system Liouvillian | ||

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g_amp - gradient amplitude, Gauss/cm | g_amp - gradient amplitude, Gauss/cm | ||

− | + | ||

s_len - sample length, cm | s_len - sample length, cm | ||

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g_dur - gradient pulse duration, seconds | g_dur - gradient pulse duration, seconds | ||

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s_fac - gradient shape factor, use 1 for | s_fac - gradient shape factor, use 1 for | ||

square gradient pulses | square gradient pulses | ||

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− | ''Version 2.2, authors: [[Ilya Kuprov]]'' | + | ''Version 2.2, authors: [[Luke Edwards]], [[Ilya Kuprov]]'' |

## Revision as of 11:32, 14 August 2018

Emulates the effect of a gradient pulse on the sample average density matrix using Edwards formalism. It is assumed that the effect of diffusion is negligible, that the gradient is linear, and that it is antisymmetric about the middle of the sample.

## Contents

## Syntax

rho=grad_pulse(spin_system,rho,g_amp,s_len,g_dur,s_fac)

## Arguments

rho - spin system state vector L - system Liouvillian g_amp - gradient amplitude, Gauss/cm s_len - sample length, cm g_dur - gradient pulse duration, seconds s_fac - gradient shape factor, use 1 for square gradient pulses

## Outputs

rho - spin system state vector, integrated over the spatial coordinate

## Examples

See examples/fundamentals/gradient_test_1.m file for an example of using this function.

## Notes

- The function integrates over sample coordinates - subsequent gradient pulses would not refocus the magnetization that it has defocused. To simulate a gradient sandwich, use grad_sandw.m function. More information on the subject is available in Luke's paper (http://dx.doi.org/10.1016/j.jmr.2014.01.011).
- This function is OK for standalone crusher gradients; for more sophisticated gradient work, use the imaging context.

## See also

*Version 2.2, authors: Luke Edwards, Ilya Kuprov*