Experimental Setup of FT-ICR-MS

For FT-ICR-MS, the ICR cell itself must not necessarily differ from one used in scanning ICR-MS (Fig. 4.51). Two of the four side walls (jc-axis) of the ICR cell are connected to the RF power supply during the period of excitation. Then, the image current induced in the detector plates (y-axis) is recorded as transient signal for some period of time (0.5-30 s). The excitation of the ions within the ICR cell has to stop at a level low enough to avoid wall collisions of the lightest ions to be measured. [191,200,201] 

Note In ICR cells, the ions circulate like separate swarms of birds rather than like matter in the rings of Saturn. If ions of the same m/z non-coherently circulated at the same frequency and radius, but occupied the total orbit rather than a small sector of it, there would be no image current induced upon their passage at the detector plates. 

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