Development of a millimeter wave, frequency tunable gyrotron using a permanent magnet system

使用永磁体系统开发毫米波频率可调陀螺仪

基本信息

批准号：
12680476
负责人：
OGAWA Isamu
金额：
$ 2.3万
依托单位：
Fukui University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12680476/
关键词：
permanent magnet higher harmonic gyrotron axis-encircling electron beam millimeter wave gyrotron

项目摘要

A novel, compact, high harmonic gyrotron with axis-encircling electron beam and permanent magnet system has been developed.It is based on a relatively new and less studied principle known as large-orbit gyrotron (LOG). Due to the greater mode separation and, hence, selectivity in such devices a single mode operation at higher harmonics can be obtained easier compared with the conventional gyrotrons. The device has been optimized for operation at the fourth harmonic of the cyclotron frequency and is suitable as a source of radiation in the millimeter wave spectroscopy. The use of a permanent magnet instead of superconducting one has several clear advantages such as easier and more economical operation and maintenance, smaller weight and dimensions, simple power supply. All these advantageous characteristics make the developed gyrotron applicable to a number of other fields where powerful portable sources of radiation with frequency around 100 GHz are needed. A theoretical investigations … More based on a computer simulations of both electron beam formation and beam-field interaction have been performed in order to study the operation of the gyrotron in a broad parameter space and to select the optimum conditions. The results were used to specify the requirements to the entire system taking into account the limitations which stem from the available power supply (accelerating voltages in the range 35-40 kV, beam currents 1-1.5 A) and attainable magnetic field (about 1 T).As a result of a computer-aided design (CAD) a high performance electron-optical system has been developed. It is based on a novel type of electron gun which uses a gradual (instead of abrupt) reversal of the magnetic field to form axis-encircling electron beams with appropriate parameters. The configuration of the electron-optical system has been optimized in an iterative process during which both the geometry of the electrodes and the magnetic field distribution were varied searching for a superior combination. The final design has been carried out using the measured magnetic field distribution inside the real permanent magnet.Although there is a noticeable deviation between calculated and measured field profiles the basic beam quality parameters (velocity ratio, velocity spread and beam ripple) are close to the required. In order to correct the field distribution produced by the real magnet we plan to include a set of additional coils for fine tuning in the final design which is near completion now.The magnetic circuit consists of a high-grade NdFeB permanent magnet. It includes axially (in the region of the resonant cavity) and radially (in both gun and collector regions) magnetized segments. The computer aided design of the magnetic system has been carried out using the ELF/MAGIC code. The permanent magnet has been produced and measured by Shin-Etsu Chemical Co. Ltd. The whole gyrotron tube will be fabricated by the Institute of Applied Physics of the Russian Academy of Sciences in N.Novgorod. Less

一种新型、紧凑、高谐波回旋管，具有绕轴电子束和永磁体系统。它基于一种相对较新且研究较少的原理，称为大轨道回旋管（LOG），由于具有更大的模式分离度和稳定性。因此，与回旋加速器相比，此类设备在高次谐波下的单模操作更容易获得选择性。该设备已针对回旋加速器频率的第四次谐波操作进行了优化，并且适合作为回旋加速器频率的第四次谐波的操作。使用永磁体代替超导磁体具有几个明显的优点，例如更容易、更经济的操作和维护、更小的重量和尺寸、更简单的电源，所有这些优势特性使得所开发的回旋管适用于毫米波光谱。许多其他领域需要频率约为 100 GHz 的强大便携式辐射源，为了研究其运行情况，已经进行了基于电子束形成和束场相互作用的计算机模拟的理论研究。考虑到可用电源（35-40 kV 范围内的加速电压、束电流）的限制，结果用于指定整个系统的要求。 1-1.5 A）和可达到的磁场（约 1 T）。通过计算机辅助设计（CAD），开发了一种基于新型电子枪的高性能电子光学系统。磁场逐渐（而不是突然）反转，以形成具有适当参数的绕轴电子束。电子光学系统的配置在电极和磁场的几何形状的迭代过程中得到了优化。为了寻求更好的组合，最终的设计是使用测量的真实永磁体内部的磁场分布进行的。尽管计算的磁场分布和测量的磁场分布之间存在明显的偏差，但基本光束质量参数（速度比、速度）。传播和光束纹波）接近所需的值，为了校正真实磁体产生的磁场分布，我们计划在目前已接近完成的最终设计中包含一组额外的线圈进行微调。磁路由一个高磁体组成。它包括轴向（在谐振腔区域）和径向（在枪和收集器区域）磁化部分，磁系统的计算机辅助设计是使用 ELF/MAGIC 代码进行的。磁铁由信越化学有限公司生产和测量。整个回旋管将由位于北诺夫哥罗德的俄罗斯科学院应用物理研究所制造。