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Z31980_00_03
Installation
6.11 Tuning and Matching the Probe
6.11.1 General Information about the Fourier Probe
The Fourier system is delivered with a special probe. It is a modified DUL probe with
13C and 2H on the inner coil and 1H on the outer coil. The special feature is a coil
design which is much less susceptible to the salt content of the sample. Tuning and
matching are much less influenced by a change of the sample. Therefore, the probe is
tuned and matched once and this calibration is not changed on a running system. The
side effect is a lower S/N ratio by about 15% compared to a normal DUL probe.
There are no tuning and matching rods on the bottom of the probe. The tunable capaci-
tors are accessible via small holes in the upper part of the probe body. Use the screw-
driver coming with the probe to tune and match the probe before installing it into the
shimsystem.
The wobb routine of the Avance system doesn’t work with the Fourier. Instead, there is a
special wobb program which must be started outside of TopSpin.
See also chapter "Additional Test Applications" on page 114 for details.
6.12 The Gradshim Command
In order to enable automatic shimming, the probe is equipped with a z gradient. Unfortu-
nately, TopShim doesn’t fit to the pulse programmer structure of the Fourier system.
Therefore, Gradshim is used instead.
It should be noted that only z gradients can be used for shimming. The focus is not so
much on the ease of installation but more on the automatic shimming when the spec-
trometer is running in automation.
Gradshim works best when the shim map was made with an already well shimmed mag-
net. You can also use a shim map from another system to get started, since the Fourier
Shim Control and BOSS 1 Shim Systems are fairly consistant.
Also important for the success of gradshim are:
• The gradient echo is nicely centered in the spectral width - check by loading and
running the experiment gradshim1d2h_f.
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