APPARATUS FOR ALLOWING INSULATING SAMPLE IN ANALYTICAL INSTRUMENT TO HAVE NEARLY UNIFORM SURFACE POTENTIAL

摘要

PROBLEM TO BE SOLVED: To uniform a surface potential of an insulating sample by projecting electron beams of low energy to a sample area while a projection area outside a radiation area is kept in a negative charge stage and directing positive ions to the projection area near the radiation area. SOLUTION: X rays 6 illuminate a radiation area 12 of a sample 2, whereby photoelectrons are emitted. An electron gun 7 projects electrons of low energy to the sample 2, and a charged particle source 10 projects positive ions 11 of low energy of not larger than about 10eV to the sample 2. Both the electron gun 7 and the charged particle source 10 are controlled by a computer 13. The radiation area 12 is positively charged because of the emission of photoelectrons. A projection area 14 to which low energy electrons are projected is larger than the radiation area 12, including the radiation area 12, and therefore positive charges are neutralized. However, excessive negative charges are produced in an area outside the radiation area 12. For neutralizing the excessive negative charges, beams of positive ions 11 are projected to a part 16 of the area near the radiation area 12. A surface potential of the sample 2 can be schematically uniformed according to the method.