DOSY Experiments - Emory University

awm
nugcal_[1-5]
0 selects absolute value experiment
1 selects phase sensitive experiment
a 5-membered parameter array summarizing the results of the
calibration of non-uniform field gradients. Created by the
Doneshot_nugmap sequence and then copied to the corresponding
probe file
probe_ stores the probe name used to acquire the DOSY experiment
NOTE: Select the transmitter offset tof to be on-resonance on the HDO signal.
The parameters for the heating gradients (gt4, gzlvl4) are calculated in the sequence. They
cannot be set directly.
The calibration is typically done by measuring 1 H profiles using the standard doped 1%
H2O/99%D2O sample; the temperature dependence of diffusion coefficient for this sample can be
estimated by interpolation from values in the literature.
To set up the Doneshot_nugmap gradient mapping experiment, do the following:
1. Calibrate the probe temperature using one of the standard samples.
2. Insert the doped 1% H2O/99% D2O sample into the magnet.
3. Regulate the probe (VT) temperature and note the (calibrated) sample temperature.
4. Optimize the lock parameters, tune the probe and shim the sample.
5. Ensure that the correct probe has been selected in VnmrJ by clicking on the Probe
button on the Hardware Bar and selecting the appropriate probe file.
6. Call the Doneshot_nugcal macro from the command line.
7. This will set up the parameters for the Doneshot_nugmap sequence that allows the
measurement of a set of diffusion-weighted profiles for characterizing the gradient nonuniformity.
Select the transmitter offset tof to be on-resonance on the HDO signal.
Review the parameters from the Acquire-Defaults and/or Acquire-Pulse Sequence
panels, as shown in Figure 1 below.
8. Click Acquire to start the acquisition.
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