共振慢波静电感应型肖特基探针研制

Schottky Detector plays a very important role as one of non-interceptive beam diagnostic components for heavy ion or proton circular accelerator. The Schottky signal can be used for studying the machine parameters of the accelerator, the precise mass measurements, and the stochastic cooling system. However, the electrostatic capacitance Schottky detector installed in HIRFL-CSRm can’t detect the Schottky signal for the beam current of nA，due to the limitation of the structure itself. It is very bad for the HIRFL-CSR normally commissioning and tuning. This project will develop a new high sensitivity Schottky detector to detect beam current of nA. Based on the concept of electrostatic pickup, a new structure will be studied, which will include a resonant structure with the high Q value and a slow wave structure with the phase velocity matched to the beam energy. These structures will be mixed together in order to improve the sensitivity of Schottky detector. New resonant slow wave electrostatic Schottky detector with a resonant frequency of 7 MHz, phase velocity of 0.2 and high Q value will be designed, fabricated and tested on beam in this project. The purpose of new Schottky detector is to meet the requirements of detecting heavy ion beam with nA current, helping to measure the precise mass of atom and studying the machine parameters of HIRFL-CSR. Meanwhile we hope to get some useful theories and experiences from this new Schottky detector, to help the design and the application of Schottky detector for the heavy ion or proton beam in the world.

肖特基探针是重离子质子环形加速器中非常重要的非拦截式探针。利用肖特基探针感应束流肖特基信号，可以进行机器研究、原子核质量寿命测量以及随机冷却系统的应用。但目前HIRFL-CSR主环安装的容性肖特基探针由于结构限制导致灵敏度低，无法感应到nA级弱束流信号，为HIRFL-CSR机器研究和高精度原子核质量测量增添很大困难。本课题拟在静电感应结构的基础上，开展一种新的综合共振结构和慢波结构的研究，通过慢波结构降低电磁行波相速度和共振结构提高品质因数Q值的方法，提高探针灵敏度，研制出一套能够感应nA级重离子束流、谐振频率为7MHz左右、匹配束流速度为0.2左右以及高Q值的共振慢波静电感应型肖特基探针，用来满足HIRFL-CSR弱束流测量、机器参数研究和原子核质量高精度测量的迫切需求。同时希望该项目研究成果为国内国际重离子质子束肖特基探针研制提供实际可行的理论研究结论与工程应用经验。

肖特基探针是重离子质子环形加速器中非常重要的非拦截式探针。利用肖特基探针感应束流肖特基信号，可以进行机器研究、原子核质量寿命测量以及随机冷却系统的应用。本课题在静电感应结构的基础上，开展一种新的综合共振结构和慢波结构的研究，通过慢波结构降低电磁行波相速度和共振结构提高品质因数方法，提高探针灵敏度，研制出一套能够感应nA级重离子束流的共振慢波静电感应型肖特基探针，测量了C4+ 190 nA@7 MeV/u的重离子束流时域信号与频域Schottky信号。该探针具有高灵敏度，高信噪比，能够感应nA级束流信号的特点，满足设计要求。