A Fully-Sealed Carbon-Nanotube Cold-Cathode Terahertz Gyrotron

Abstract

Gigahertz to terahertz radiation sources based on cold-cathode vacuum electron technology are pursued, because its unique characteristics of instant switch-on and power saving are important to military and space applications. Gigahertz gyrotron was reported using carbon nanotube (CNT) cold-cathode. It is reported here in first time that a fully-sealed CNT cold-cathode 0.22 THz-gyrotron is realized, typically with output power of 500 mW. To achieve this, we have studied mechanisms responsible for CNTs growth on curved shape metal surface, field emission from the sidewall of a CNT, and crystallized interface junction between CNT and substrate material. We have obtained uniform growth of CNTs on and direct growth from cone-cylinder stainless-steel electrode surface, and field emission from both tips and sidewalls of CNTs. It is essential for the success of a CNT terahertz gyrotron to have such high quality, high emitting performance CNTs. Also, we have developed a magnetic injection electron gun using CNT cold-cathode to exploit the advantages of such a conventional gun design, so that a large area emitting surface is utilized to deliver large current for electron beam. The results indicate that higher output power and higher radiation frequency terahertz gyrotron may be made using CNT cold-cathode electron gun.

Field Emitters Using Inverse Opal Structures

“…The emitted electrons can be used for a number of important applications including field emission displays, X‐ray spectroscopy sources, harsh environment electronics, and high‐speed electronics . The combination of ballistic conduction through a vacuum channel, the inherently fast emission process, and the ability to operate at high temperatures has made field emission a topic of intense interest for two decades . Additionally, field emission devices are particularly relevant for space‐based applications because of their resilience in high radiation and high temperature environments .…”

Design and Simulation of a Multi-Sheet Beam Terahertz Radiation Source Based on Carbon-Nanotube Cold Cathode

“…Since the discovery of carbon nanotubes (CNTs), they have received wide attention as a promising FE cold cathodes material due to their high electrical conductivity, large aspect ratio, and excellent chemical and temporal stabilities [17]. They have unprecedented potential and have proven to be an enabling technology towards the manufacture of FE-based flat-panel displays, high-performance X-ray sources and, more recently, cold cathode VEDs [18][19][20][21][22]. As their emission current density increases significantly as the cathode size decreases, CNT based FE electron sources are very well suited for the required aggressive miniaturization needed for THz VEDs.…”

Стабильность Полевой Эмиссии Одиночной Углеродной Нанотрубки

“…Поэтому не удивительно, что в 1995 г. появилось несколько работ, в которых описыва-лось явление полевой эмиссии из УНТ [2][3][4]. Это явле-ние легло в основу ряда важных с точки зрения практики применений: плоских экранов мониторов [5,6], миниа-тюрных рентгеновских трубок [7,8], светоизлучающих устройств [9,10], миниатюрных вакуумных ламп [11,12], усилителей терагерцового диапазона [13,14], высокоча-стотных вакуумных переключателей [15].…”