Observations of electron emission sites on broad area electrodes by an electron emission microscope

• Published in: Applied surface science Vol. 144; pp. 118 - 122
• Main Authors: Kobayashi, S, Saito, Y, Mizusawa, T, Shirai, K, Latham, R.V, Tajiri, K, Yamanaka, Y
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.1999; Elsevier Science
• Subjects: Broad area electrodes; EEM; Electron emission sites; Electron, positron and ion microscopes, electron diffractometers and related techniques; Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Physics; pit-free electropolishing; EE; Electron emission sites; Broad area electrodes; pit-free electropolishing; Field emission 79.70; EEM; Electrodes; Electropolishing; Instrumentation; Field emission microscope; Aluminium; Electron emission; Experimental study
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/S0169-4332(98)00782-X

To observe field electron emission sites which lead vacuum gaps to electrical breakdown an electron emission microscope (EEM) has been developed. The microscope consists of three unipotential lenses, that is, objective, intermediate and projection lenses. A plane electrode of the objective lens facing the cathode has a 0.5 mm diameter pinhole which extracts field emitted electrons, and works as an anode. This plane anode form enables the observation of emission sites on a broad area cathode. By using this EEM changes of emission site aspects on pit-free electropolished Al cathodes before and after 500 breakdowns were observed. Images recorded showed that field emission occurs at several isolated sites rather than one site. Also revealed is that the number of emission sites after 500 breakdowns did not increase significantly.