| 摘要 |
PURPOSE:To improve an S/N ratio and to enhance voltage measuring accuracy by providing a disk shaped microchannel plate so as to cover a semispherical grids in a device which analyzes the energy of a secondary electron beam emitted from a specimen when an electron beam is irradiated to the specimen, thereby enhancing trapping rate of secondary electrons. CONSTITUTION:The specimen 3 is arranged in a grid group 1 comprising semispherical grids G1-G3. The large area microchannel plate 11 is arranged over the grid G3. Said microchannel plate 11 comprises a substrate 11a and an anode part 11b, and is shaped in a disk shape. A central hole 11c, through which the electron beam 5 irradiated on the specimen 5 passes, is formed at the center thereof. The secondary electrons 5a, which are emitted from the specimen 3 when the electron beam 5 is irradiated on the specimen 3, are collected by the microchannel plate 11, and amplified so as to increase sensitivity. Many small holes 11d perforated in the substrate 11a in said microchannel palte 11. The secondary electrons 5a jump into the said holes 11d and reflection is repeated. The secondary electrons are emitted from the inner walls of the holes 11d, and multiplication is accomplished. |
