Carbon nanotube cathodes for microwave and X-ray electron tubes
Most electron tubes are based on thermionic cathodes which emit large current densities ( 2 A/cm2) and exhibit long life times (15 years). However, due to the emission mechanism and to the operating temperature (1000℃), these cathodes are not adapted to tubes that require instant turn on or high frequency modulated electron beams. Carbon nanotube (CNT) cathodes are field emission electron sources, operate at room temperature and allows instant turn. The emitted current, which depends on the electric field at nanotube apex, can be modulated using a gate electrode. Recently, we proposed to use another method which is the optical control of a CNT photocathode. This photocathode is an array of vertically aligned multi-walled CNTs, each CNT being associated to a semiconducting p-i-n photodiode. Schematically, the p-i-n element acts as an optically controlled current source. This operating mode is particularly interesting for the two targeted applications which are X-ray tubes for 3D imagery and microwave tubes for satellite telecommunication.
Pierre Legagneux
Nanocarb, Thales-Ecole Polytechnique Palaiseau, France
国际会议
2010 8th International Vacuum Electron Sources Conference and NANOcarbon(第八届真空电子源和纳米碳国际会议)
南京
英文
86
2010-10-14（万方平台首次上网日期，不代表论文的发表时间）