Analyzer magnetic field

Ion cyclotron resonance analyzer. A device to determine the mass-to-charge ratio (m/z) of an ion in the presence of a magnetic field by measuring its cyclotron frequency. 

Magnetic analyzer. A direction-focusing device that produces a magnetic field perpendicular to the direction of ion travel. The effect is to bring to a common focus all ions of a given momentum with the same mass-to-charge (m/z) ratio. 

Wien analyzer. A velocity filter with crossed homogeneous electric and magnetic fields for transmitting only ions of a fixed velocity. 

Figure 6 shows the sequence of events in a laser desorption FTMS experiment. First, a focused laser beam traverses the analyzer cell and strikes the crystal normal to the surface. Molecules desorbed by the thermal spike rapidly move away from the crystal and are ionized by an electron beam which passes through the cell parallel to the magnetic field and 3 cm in front of the crystal. 

Fourier transform mass spectrometry is made possible by the measurement of an AC current produced from the movement of ions within a magnetic field under ultra-high vacuum, commonly referred to as ion cyclotron motion.21 Ion motion, or the frequency of each ion, is recorded to the precision of one thousandth of a Hertz and may last for several seconds, depending on the vacuum conditions. Waveform motion recorded by the mass analyzer is subjected to a Fourier transform to extract ion frequencies that yield the corresponding mass to charge ratios. To a first approximation, motion of a single ion in a magnetic field can be defined by the equation... 

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