Cycloidal mass spectrometer

A cycloidal mass spectrometer was devised by Bleakney and Hipple which operates with crossed magnetic and electrostatic fields. Measurements by other workers show that with a magnetic field of 5000 gauss, masses 1-500 can be detected. Adjacent mass numbers are separable up to 100, but the resolution decreases for higher mass numbers. Partial pressure detection down to 10" torr is claimed. 

Crossed electric and magnetic fields have been used for mass analysis in several mass spectrometers but do not have wide application despite their perfect double focusing. The first cycloidal mass spectrometer was constructed in 1938 by Bleakney and Hippie A commercial instrument... 

Figure 1 shows a schematic view of a typical ICR spectrometer. The operation of most current ICR spectrometers may be generally described as follows. Ions are produced by an electron beam in an ion source just as in any mass spectrometer. (In Fig. 1, the source region is denoted by A.) A uniform magnetic field B is oriented along the z axis and a dc electric field Fj is present in the y direction. An ion in crossed dc electric and magnetic fields (Section 2.5) will drift in the x direction following a cycloidal trajectory with a characteristic frequence of revolution co -... 

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