| 摘要 |
PURPOSE:To analize accurately without reducing the filament life by shielding an electron beam and reducing the heating power applied on the electron gun to obtain the filament cordition under the oridinary operation. CONSTITUTION:An electron gun is constituted with filament 1, Wehnelt cylinder 2, and anode 3, and an electron gun chamber is sealed with a valve 4 to maintain the vacuum in a container of an electron optical system when the filament is exchanged. The filament 1 is heated with a heating voltage source 14, the filament itself is connected to a high voltage source 13 through a bias resistor 15 to maintain a volaage between a cylinder 2. The valve 4 is for shielding the electron gun chamber, the valve is used to shield the electron beam 10 by operating it when a sample is changed. Thus the analysis can be performed efficiently and the life of a filament can be increased. |
