| 摘要 |
PROBLEM TO BE SOLVED: To prevent occurrence of an electron beam of an unintentional large current.SOLUTION: An electron gun 10 includes a cathode 11, a Wehnelt electrode 12, a control electrode 13, an anode 14, and a control part 25. The control part 25 controls an output value and output timing of a bias voltage to be changed by a bias supply 22, and an output value and output timing of a control voltage to be changed by a control electrode supply 23 so that a beam current generated by an electron beam B1 to be emitted toward a powder sample 8 reaches a set current value. |
