Patent ID: 9318300
Filing Date: 2016-04-19
CPC Classification: H01J

Claim Text:
1. A charged particle beam instrument for permitting an observation of a specimen in a gaseous atmosphere, said charged particle beam instrument comprising: a specimen chamber that accommodates the specimen; a gas supply pipe for supplying a gas into the specimen chamber; a venting portion for venting the specimen chamber; a gaseous environment adjuster including a gas inflow rate adjusting valve for adjusting the flow rate of the gas flowing through the gas supply pipe and a first vacuum gauge for measuring the pressure of the gas supplied into the specimen chamber; and a gas controller for controlling the gaseous environment adjuster; wherein said gas controller sets a target value of pressure for the gas flowing through the gas supply pipe based on a predetermined relational expression indicating a relationship between the reading of the first vacuum gauge and the pressure inside the specimen chamber and on a corrective coefficient for correcting the reading of the first vacuum gauge according to the species of the gas being supplied into the specimen chamber and controls the gas inflow rate adjusting valve such that the reading of the first vacuum gauge reaches the target value of pressure.