Related Experiment Video
Updated: Jun 27, 2026

Preparing a Celadonite Electron Source and Estimating Its Brightness
Published on: November 5, 2019
Design of a simple annular electron beam source and its operating characteristics in single and repetitive shot modes
1College of Photoelectric Science and Engineering, National University of Defense Technology, Changsha 410073, People's Republic of China. newages1979@yahoo.com.cn
Abstract:
In this work, design and performance of an annular carbon fiber cathode are presented. Measurements on this cathode were performed in a single high-voltage pulse generator (600 kV, 50 ns, and 50 Omega) and a repetitive one (350 kV, <10 ns, 180 Omega, and 100 Hz), respectively. In a single pulse regime, emphasis was placed on the uniformity of electron beam extracted from this cathode. It was found that this cathode could deliver uniform electron beams with current densities exceeding kA/cm(2). Cesium iodide (CsI) coating eliminated hot spots on the cathode surface, significantly improving the uniformity of electron emission. Under repetitively pulsed operation, this cathode exhibited a good shot-to-shot reproducibility at the pressure of 1.5x10(-4) Torr, suggesting an ability of surviving even in poor vacuum. However, once the base pressure rose up to 3.76x10(-4) Torr, the cathode performance gradually degraded as the pulse shot proceeded. Besides, some possible explanations for these experimental results are presented. These results show that given proper diode design, carbon fiber with CsI coating has great promise as electron emitter producing high-current electron beams.
Related Concept Videos
Overview of Electron Microscopy
Atomic Emission Spectroscopy: Instrumentation
Transmission Electron Microscopy
Atomic Absorption Spectroscopy: Radiation and Light Sources
Two common narrow-range 'line' sources used in AAS are hollow-cathode lamps (HCLs) and...
Scanning Electron Microscopy
Fundamental Principles
Accelerated...
Electron Orbital Model
