Development of a Feasible High-Power mm Microwave Pulse Source Utilizing Superconducting Cavity

利用超导腔开发可行的高功率毫米微波脉冲源

基本信息

批准号：
60850014
负责人：
MINAMI Kazuo
金额：
$ 7.55万
依托单位：
Niigata University (1986)Tokyo Institute of Technology (1985)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

项目摘要

It is the purpose of the present project to develop a feasible mm microwave pulse sourse, utilizing the storage and quick extraction of energy from a superconducting cavity, in which the time constants can be of the order of <10^(-2)> sec. In the first year, we designed and constructed a niobium cavity, a mm microwave AFC circuit and a FRP cryostat etc. Moreover, small semi-circular discharge tubes with 20-50 Torr helium gas at room temperature were designed to use for the output discharge antenna. Niobium cavity was designed to be <TE_(0,1,17)> cylindrical mode with resonant frequency 24.5 GHz, and the inner diameter 44 mm, the length 111 mm. In the next year, i.e., the final year of the project, we first measured precisely the frequency characteristic of the niobium cavity at room temperature. Various parameters of the cavity were obtained. The resonant frequency and the loaded Q value were, respectively, 23.77 GHz and 2x <10^3> . To increase the loaded Q value of niobium cavity, we electro-polished The inner surface of the niobium cavity, in which the roughness of the surface was estimated to be less than 0.1 <micro> m. In the electro-polishing solution, the DC current with 60 mA/ <cm^2> was given between a niobium anode and the part of the niobium cavity, i.e., the two disks and the cylinder, respectively. Electro-polishing took 4 hours. Then, the parts were fabricated quickly in a clean room. After evacuating and baking, vacuum inside the cavity was attained to be 3x <10^(-8)> Torr. The electro-polished cavity was considered to have loaded Q value of the <10^8> at helium temperature 4.2 K. At this moment, we are carrying out the final experiment to give the voltage 20 kV, current 2000 A, time width 1 <micro> sec to the discharge antenna. We are expecting to have the final purpose of the present project, i.e., pulse power gain of <10^4> .

本项目的目的是利用从超导腔中的储存和快速提取能量的可行MM微波脉冲酸味，在该腔体中，常数可以达到<10^（ - 2）> sec的顺序。在第一年，我们设计并构建了一个niobium腔，MM微波AFC电路和FRP低温恒温器等。此外，在室温下，具有20-50台吨氦气的小型半圆形放电管设计用于输出放电天线。 Niobium腔的设计为<te_（0,1,17）>具有谐振频率24.5 GHz的圆柱模式，内径为44毫米，长度为111 mm。在第二年，即项目的最后一年，我们首先在室温下精确测量了niobium腔的频率特征。获得了腔的各种参数。共振频率和加载的Q值分别为23.77 GHz和2x <10^3>。为了增加niobium腔的载荷Q值，我们电抛光了Niobium腔的内表面，其中估计表面的粗糙度小于0.1 <micro> m。在电抛光溶液中，分别在niobium阳极和niobium腔的部分（即两个磁盘和圆柱体）之间给出了60 mA/ <cm^2>的直流电流。电抛光花了4个小时。然后，将零件迅速在干净的房间里制造。撤离和烘烤后，腔体内的真空度为3x <10^（-8）> torr。在氦气温度4.2 K处，电抛光的腔被认为已加载了<10^8>的Q值。此时，我们正在进行最终实验，以使电压为20 kV，当前2000 A，时间宽度1 <micro> <micro> sec sec至放电天线。我们期望具有本项目的最终目的，即脉冲功率增益<10^4>。