A faculty in my school recently purchased a diffusion probe from Doty with
Varian performa III amplifyer (Highland L700). It will be used on a
Unity+400 NMR instrument. Since I have no any experience on diffusion NMR,
here are some basic questions, hope someone can give me a hand:
1. How do I know the coil of the probe is in the center of the field?
This probe does not need air to spin, eject and bearing, so the upper
barrel will not be used to adjust the vertical position of the probe.
2. How to adjust the depth of the sample tube so the center of the sample
will match the center of the coil?
The sample tube will be inserted from top of the probe with a tight tube
holder permenently mounted on the probe, then the whole set will be
inserted to the magnet from the bottom. Is there any gauge to adject the
depth of the tube?
3. What is the regular sample volumn/height for a 5mm tube?
4. What kind of sample should be used for shimming? Does it require Lock?
Any commemt is highly appreciated and will be posted in a summary.
Qing Ning
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Qing Ning, Ph.D
NMR Specialist Analytical Service Lab
q-ning@nwu.edu Department of Chemistry
tel. 847-491-7080 Northwestern University
Fax 847-491-7713 2145 Sheridan Road
Evanston, IL 60208