| 摘要 |
PURPOSE:To prevent an increase of the secondary aberration coefficient even though the curvature arranged at the incident side surface of a magnetic field comprising a mass analysis field is somewhat apart from the ideal value, by furnishing a hexode lens in t specific position of an ion optical system. CONSTITUTION:A double focusing mass spectrometer is formed with a curvature R at the incident or emission side surface of a magnetic field 3 with a rotating radius rm. A hexode lens 6 is placed in an optical position where an equation is set up as follow: aalphaalpha/aalphadelta=balphaalpha/balphadelta Where primary members are aalphaalpha and aalphadelta in a taylor development of the secondary aberration coefficient Aalphaalpha and Aalphadelta related to the lateral expansion angle of ion beam alpha and the width of energy delta, depending on the parameter rho=rm/R, and the effects of the hexode lens 6 of an intensity h to the secondary aberration coefficient Aalphaalpha and Aalphadelta are hbalphaalpha and hbalpha. Therefore the increased secondary coefficient generated from a gap between the curvature and the ideal value can be well corrected. |
