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

Ningsheng Xu,Shaozhi Deng,Jianqiang Wu,Xuesong Yuan,Weiwei Zhu,Juncong She,Yang Yan,Yu Zhang,Yan Shen,Jun Chen

doi:10.1038/srep32936

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.

Highlights

High frequency vacuum electron radiation source is one important kind of devices that communication, satellites and spacecraft rely on widely
Carbon nanotube (CNT) is the excellent field electron emitter; its field emission property with high current density has been reported by many authors including ourself[12,13]
We demonstrate in this work that one can realize a cold-cathode terahertz-gyrotron using CNTs as field electron emitters

Summary

Introduction

High frequency vacuum electron radiation source is one important kind of devices that communication, satellites and spacecraft rely on widely. The cold cathode is an ideal candidate for electron sources of high frequency radiation source device, which has the advantages of fast switch-on time and room working temperature, and can be minimized in the size of device and achieved functional integration of devices. As so-called fast-wave vacuum electronic device, is based on the stimulated radiation of electron cyclotron resonance. It is one of the most important terahertz sources that can generate high power radiation in the millimeter-wave and terahertz frequency region. We decided to exploit the advantages of existing electron gun design, rather than having a new one In this case, it is a conventional magnetic injection electron gun, where the cathode electrode is in cone-cylinder shape.

Methods

Results

Conclusion