| 摘要 |
PURPOSE:To facilitate high resolution analysis by forming a focusing point at a source slit position by an electrostatic lens system and driving a multipole electrostatic lens so that a virtual image at the focusing point comes to the position of a detection slit. CONSTITUTION:When MS/MS (Multi Stage Mass Spectrometry) is performed, ions generated from an impingement room 23 in a lens system 22 are focused at a position of a slit 24. Resultingly, the position of the focusing point on a side of MS2 is shifted from the position of a detection slit 20 to that of slit 24, in comparison with the case of single mass spectrometry. Thereupon, a multipole electrostatic lens 21 such as a quadrupole electrostatic lens is driven so that a virtual image of the focusing point formed on the slit 24 comes to the position of the detection slit 20. Therefore, because the focusing point is formed at the position of the detection slit 20, on the side of MS2, so as to obtain operation as if a source slit exists there, double focusing can be secured similarly as in the case of single mass spectrometry and so high resolution can be maintained. |
