| 摘要 |
PCT No. PCT/GB89/00784 Sec. 371 Date Mar. 11, 1991 Sec. 102(e) Date Mar. 11, 1991 PCT Filed Jul. 10, 1989 PCT Pub. No. WO90/00810 PCT Pub. Date Jan. 25, 1990.A low pass filter for use in an image band pass filter of a photoelectron spectromicroscope incorporating a virtual potential surface for reflecting electrons below a particular energy and a special charged particle trap or super dump for unwanted electrons. The filter construction with the super dump reduces the proportion of elastically and inelastically scattered high energy electron escaping the filter. |
