| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem that, in a conventional delay withdrawal method, an m/z range in which an appropriate energy convergence is attained is narrow and an m/z range in which resolution is improved is narrow as well because difference in m/z is not taken into account when ion is accelerated. <P>SOLUTION: At the time when ion is generated by radiating laser light to a specimen S, a withdrawal electric field is formed which has a potential gradient coming down gently toward a withdrawal electrode 3 from a specimen plate 1 (U). Under the action of the electric field, the ion is almost separated according to m/z in a withdrawal region, and the ion of large m/z remains near the specimen S. After a delay time t elapses, a voltage applied to the specimen plate 1 and an auxiliary electrode 2 is raised, to form an acceleration electric field having a potential gradient R which looks like a kinked line. Since the electric field is close to an ideal potential gradient curve Q, an appropriate potential energy change can be applied to the ion at each m/z, allowing an appropriate energy convergence across a wide m/z, resulting in improved resolution. <P>COPYRIGHT: (C)2013,JPO&INPIT |
