| 摘要 |
Ion cage mass spectrometer, also referred to as quistor or ion trap, comprising a ring electrode and two end cap electrodes, voltage supplies for generating an ion-storing HF-quadrupole field, means for generating ions of the substances to be mass-spectrometrically investigated inside or outside the ion cage, potentially means for introducing the ions into the ion cage, means for the documentation of such ions that emerge from the ion cage, characterized in that a hexapole potential Pq=(A2/4z02) * (r2-2z2) [U-V cos ( omega t)] or an octopole potential Ps=(A3/4z03) * (3r2z-2z3) * [U-V cos ( omega t)], or a linear combination of both is exactly or approximately superimposed on the exact quadrupole potential P0=(A4/4z04) * (r4+8z4/3-8r2z2) * [U-V cos ( omega t)], by special shaping of the electrodes, wherein r=distance from the z-axis, z=distance from the plane z=0, Z0=distance of the end cap from the center z=0, A2=strength of the quadrupole field, A3=strength of the hexapole field, A4=strength of the octopole field, U=value of the DC voltage, V=peak value of the AC voltage, omega =radian frequency of the AC voltage, and t=time.
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