PROJECTION-TYPE CHARGED PARTICLE OPTICAL SYSTEM AND IMAGING MASS SPECTROMETRY APPARATUS

摘要

Provided is a projection-type charged particle optical system in which a projection magnification can be changed while a decrease in the accuracy in measuring a mass-to-charge ratio is being suppressed. A projection-type charged particle optical system according to the present invention includes a first electrode disposed so as to face a sample and having an opening formed therein for allowing a charged particle to pass, a second electrode disposed on a side of the first electrode opposite to where the sample is disposed and having an opening formed therein for allowing the charged particle to pass, and a flight-tube electrode disposed such that the charged particle that has been emitted from the sample and has passed through the second electrode enters the flight-tube electrode and being configured to form a substantially equipotential space thereinside. A principal plane is formed at at least two positions in a travel path of the charged particle.

主权项

1. A projection-type charged particle optical system, comprising:
a first electrode disposed so as to face a sample, the first electrode having an opening formed therein for allowing a charged particle to pass therethrough; a second electrode disposed on a side of the first electrode, the side being opposite to where the sample is disposed, the second electrode having an opening formed therein for allowing the charged particle to pass therethrough; and a flight-tube electrode disposed such that the charged particle that has been emitted from the sample and has passed through the first and second electrodes enters the flight-tube electrode, the flight-tube electrode being configured to form a substantially equipotential space thereinside, wherein the projection-type charged particle optical system has an operation mode in which a potential applied to the first electrode is higher than a potential of the flight-tube electrode and a potential applied to the second electrode is lower than the potential of the light-tube electrode.