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6.3 Testing CRAMPS NMR
01-999044-00 C0501 UNITY INOVA Solids Hardware Installation
51
If the probe does not make the specification, check for rf losses in the decoupler
circuitry.
12. Note the value of
dpwr
because it is used for
level2
during future tests.
6.3 Testing CRAMPS NMR
For CRAMPS installations, the NMR tests break into two parts: the tune-up pulse
sequences and probe-dependent multipulse experiments. The following list of tune-up
pulse sequences should be performed on a liquid sample of benzene and Cr(acac)
3
(Part
No. 00-958984-87) at all installations:
•
FLIPFLIP
•
FLIPFLOP
•
MREV8
• 1
H wideline
If the CRAMPS probe is supplied by Varian, two further spinning tests should be performed
on adipic acid:
•
MREV8
•
BR24
Before operating the cavity amplifier, it must be tuned as described in “Tuning the High-
Power (Cavity) Amplifier” on page 44 .
Testing Multipulse NMR
Use a CRAMPS probe, if available, or a wideline probe tuned to the
1
H frequency. The
following tests are performed using a test sample of benzene and Cr(acac)
3
(Part No. 00-
958984-87) in a spherical bulb. This sample, provided with the kit, is inserted into the coil
of the probe so that it is at the center of the coil. Note that is essential that the spherical
portion of the sample has no air bubbles.
Testing Basic NMR
An example spectrum of the standard
1
H observe using the S2PUL pulse sequence is shown
in Figure 22 .
1. Enter
rtp('/vnmr/stdpar/H1')
to recall parameters.
2. Enter
create('tpwrf','integer')
setlimit('twprf',4095,0,1)
, and then set
tpwrf=4095
.
3. Set the following parameters for basic NMR tests:
sw=1e4 tpwr=55 pw=1
gain=0 at=.2 d1=1 nt=1 dp='y'
4. Select LO POWER for both HI BAND and LO BAND on the solids cabinet.
5. Acquire an FID.
6. Make sure that the rf is not on-resonance and then shim on the FID to get a FWHH
(full-width at half-height) of approximately 30 Hz. For more information on FID
300 MHz 75 kHz 60 kHz 80 kHz
400 MHz 60 kHz 55 kHz 70 kHz