PARTICLE BEAM DEVICE EQUIPPED WITH ELECTRON GUN OF FIELD EMISSION TYPE AND HEAT-DEGASSING METHOD THEREOF

PROBLEM TO BE SOLVED: To efficiently exhaust evolved gas in an electron gun chamber of a field-emission type. SOLUTION: Temperature-detecting means, 27 to 31, are installed on the outer wall of an electron gun chamber 12, near a magnet 23 of an ion pump IP1 which evacuates the electron gun chamber 12, on the outer wall of an electromagnetic lens part 11 near the connecting part with the electron gun chamber 12, near a magnet 24 of an ion pump IP2 which evacuates the electromagnetic lens part 11, and near an air-locking part 25, respectively. A power source 14 for baking, which is connected to heaters, 15 to 19, is controlled by a control means 32, as the temperatures detected by each temperature-detecting means, 27 to 31, fall in the prescribed range respectively during a heat-degassing period.