| 摘要 |
PROBLEM TO BE SOLVED: To detect a disconnection even when a filament is broken in a period except for an operation of an electron beam irradiation apparatus and to specify the broken filament.SOLUTION: An electron beam detector detects a state of electron beams irradiated by an electron beam irradiation device. A wire electrode (conductor) 46 which is a plurality of conductors is disposed in association with each of a plurality of filament 25 and provided electrically insulated from each other in a region irradiated with the electron beams. A value of the current flowing through each of the plurality of wire electrodes 46 is measured by a current measuring device (measuring means) 48. A CPU (determination means) 49 determines an irradiation state of the electron beams upon receipt of signals output from the current measuring device 48. The CPU 49 determines that an abnormality occurs in the filament 25 corresponding to the conductor reduced in a current value when the current measuring device 48 measures the reduction of the current value. |
