Patent ID: 7781743

Claim:
A charged particle beam system equipped with a charged particle optics which makes a charged particle beam emitted from a charged particle source incident on a sample and means of evacuation for evacuating the charge particle optics, wherein the means of evacuation has: a vacuum vessel with a charged particle source disposed in the vessel; a non-evaporable getter pump which connects with the vacuum vessel through a vacuum pipe and evacuates the interior of the vacuum vessel as a subsidiary vacuum pump; a valve interposed in the vacuum pipe connecting between the vacuum vessel and the non-evaporable getter pump; a rough pumping port which is provided closer to the non-evaporable getter pump than the valve and performs rough pumping; an open and shut valve for opening and shutting the rough pumping port; and a main vacuum pump which is provided closer to the vacuum vessel than the valve and evacuates the interior of the vacuum vessel.