Modern NMR Instrument Architecture

Shimming by hand can be tedious. Fortimately, there are a number of automated applications that can expedite our arrival at a good shim set for a given sample. In practice, we often load a starting shim set (set of shim currents) and make improvements from there. Because every sample is unique, the optimal shims for each sample rvill similarly be unique. 

The modern NMR instrument contains three principal components the magnet, the computer, and the electronic hardware between the two. 

An NMR experiment is carried out as follows we select an experiment to run. We tell the NMR software on the host computer (the computer attached directly to the NMR instrument) what experiment we want to run, and the computer sends the appropriate set of instructions to the computer built into the NMR console. The two computers most often communicate via an Ethernet connection. The host computer will have a second Ethernet card dedicated to talking to the NMR console computer. These instructions will include  

Magnet bore tube. Syn. bore, bore tube. The hollow, cylindrical tube that runs vertically (for an NMR magnet, horizontally for an MRI magnet) through the interior of a cryomagnet. The magnetic field maximum occurs within the interior of the bore tube. The room temperature (RT) shims are a hollow cylinder that is inserted inside the bore tube, and the probe is inserted inside the RT shims. Samples are lowered pneumatically down the upper bore tube, which is a smaller tube that rests on top of the RT shims and probe assembly. 

Sample spinning.The rotation, using an air bearing, of the NMR tube/spin-ner assembly, used to average, on the NMR time scale, the strength of the applied magnetic field experienced by molecules in the sample solution. Sample spinning narrows the line widths of the peaks we observe and is almost exclusively employed in the collection of 1 -D spectra. 

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