| 摘要 |
PURPOSE:To prevent the functional form of a decelerating voltage for analysis to the output of a secondary electron quantity detector from following the decelerating voltage to change, by providing a hemispherical net-shaped buffer electrode between a leading-out electrode and a decelerating electrode for analysis. CONSTITUTION:An electron gun 2 in a vacuum vessel 1 irradiates an electron beam 3 to a sample 4, and secondary electrons 5 are generated from the sample 4. The potential of a leading-out electrode 6 is more positive than that of the sample 4, and a decelerating electrode 7 for analysis controls the quantity of secondary electrons incident to a secondary electron quantity detector 8. Meanwhile, a hemispherical buffer electrode 9 having the form similar to the leading- out electrode 6 and the decelerating electrode 7 is provided between these electrodes, and a voltage 50-100V is applied to the buffer electrode 9. Only the decelerating voltage is changed as a parameter to obtain such decelerating voltage that the output of the secondary electron quantity detector becomes constant and a potential difference between samples is obtained on a basis of the difference between these decelerating voltages. Thus, the energy resolution is improved, and the analysis characteristics are improved because of no influence of the decelerating voltage. |
