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New device concepts and materials for the fabrication of compact THz (> 100 GHz) nanoelectronic and vacuum nanoelectronic devices are of particular interest for broadband communication, security screening of packages and chemical materials, biomedical examination, and other applications. In particular, new compact and room-temperature THz imaging systems as well as environmental monitoring are...
The cold cathode x-ray source was fabricated by using the point-type CNT film emitter. The CNT x-ray source consists of the CNT point emitter, the metal mesh gate electrode and the tungsten target anode electrode. Those components were mounted in a small vacuum chamber. The fabricated CNT x-ray source shows a high resolution x-ray image at a low anode current and at a low anode voltage compared to...
We fabricated field emission electron sources and applied for the glass sealed x-ray tube for medical imaging devices. The x-ray tube consists of an electron beam with a patterned grown CNT emitters with RAP process. Those electron beam shows higher electron emission current and transmittance after glass seal. With the x-ray tube, we success to measure medical image with finger and high resolution...
We propose an advanced active current-control (ACC) unit composed of two cascade transistors for extremely stabilizing field emission currents. The upper transistor connected to the cathode modulates high voltages for field emission while the other one regulates emission current stably. Using the ACC unit developed, very stable emission currents were achieved from the fully vacuum-sealed x-ray tube...
Reducing the emission of secondary electrons from anode materials is critical to improved efficiency and increased performance in high power vacuum electronics for defense systems. The focus of this proposed effort is to leverage advances in materials technology, specifically thin films, to reduce secondary electron generation and outgassing from anode surfaces. By using advanced thin film deposition...
A traveling wave tube (TWT) based on carbon nanotube (CNT) cold cathode is theoretically researched in this paper. A magnetic injection electron gun and helix slow-wave structure is adopted in the TWT. Simulation results show that the maximum output power of the CNT TWT can reach 54 W at 9.4 GHz with an input power of 50 mW, corresponding to the maximum gain of 30 dB, when the gyrating electron beam...
The need for a low-cost, low-dose 3D imaging capability, as an alternative to CT and MRI scanners, has driven the development of a multi-cathode, stationary Digital Tomosynthesis (s-DT) scanner. Demonstration experiments with an array of cold cathodes as electron sources have been reported by multiple groups. We report the operation of a device with a different field emitter geometry, at 60kV, to...
We fabricated the point-type CNT emitter for cold cathode x-ray source applications. The CNT point emitter was made by CNT film with a triangular tip shape, which was clamped using two stainless steel plates. Electrical properties of the point-type CNT emitter measured in triode structure showed the low turn-on and threshold electric fields, the high emission current and relatively high electron transmittance...
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