Magnetic and Electromagnetic Analysers

Schematic diagram of a MALDI orthogonal acceleration TOF instrument. 

Consider an ion of mass m and charge q, accelerated in the source by a potential difference Vs. At the source outlet, its kinetic energy is 

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Process NMR makes frequent use of benchtop low-resolution (10-30 MHz) and low-field high-resolution (60 MHz) NMRs for lab (near-line) and off-line work (mainly QC), as well as on-line in-process units (10-30 MHz) which have a direct feed from the process. The lab or off-line units are necessary as a backup to the on-line process NMR in case of failure. The requirements of process NMR analysers are quite different from those of laboratory NMR instruments. For process applications, a permanent magnet or electromagnet operating at H resonance frequencies <100 MHz is preferred over cryogenic magnets. On-line NMR analysers must... 

Figure Bl.6.3 Electron energy analysers that use magnetic fields (a) the trochoidal analyser employing an electromagnet, (b) the Wien filter and (c) the sector magnet analyser. Trajectories for electrons of different energies are shown.

Figure 16.3—Magnetic analyser-based instrument. A model JMS AX505 from Jeol is shown. The characteristic shape of the electromagnet can be seen on this photograph (magnetic sector). The detector lies at the extreme right of the photograph and the ion source appears at the centre of the picture. It should be noted in the figure that the instrument is also coupled to a GC. (Reproduced by permission of Jeol, Japan.)...

Analyses of the electromagnetic field will be started from the simplest case of a uniform conducting and isotropic medium. As is known, expressions for complex amplitudes of the field caused by the magnetic dipole, oriented along the z-axis, have the form (Chapter 2) ... 

There are two main groups of analysers, non-magnetic analysers typified by quadrupoles and ion trap analysers and magnetic analysers which use permanent or electromagnets to separate the ions under the influence of a magnetic field. 

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