摘要
上海光源是第三代同步辐射光源。在上海光源的二期工程中,超导三次谐波腔将用于拉伸束团长度,提升束流托歇克寿命。三次谐波腔工作在被动模式下,谐波腔工作频率(约1.5 GHz)为主腔工作频率(约500 MHz)的三倍。为实现谐波腔高频系统的调谐控制,需要对1.5 GHz信号进行下变频处理,便于后端对信号采样处理。本文介绍了三种下变频的方案,将1.5 GHz射频信号降频为31.25 MHz中频信号,分析了各个方案的特点和影响下变频结果的因素。测试结果显示:三种变频方案在不同的动态范围具有良好的线性,均已满足谐波腔控制需求。其中基于倍频器的变频模块为最优方案,其线性动态区间大于70 dB,同时产生的中频信号的相位噪声最低,最终将在谐波腔的控制系统中采用。
[Background]Shanghai synchrotron radiation facility(SSRF)is the third generation synchrotron radiation source.In the phase II project,the third harmonic superconducting cavity will be used to improve Touschek lifetime by lengthening the bunch.[Purpose]This study aims to achieve the tuning control of the harmonic radio frequency(RF)system by frequency reduction of the 1.5 GHz signal from harmonic cavity for signal sampling in the control system.[Methods]First of all,three kinds of frequency conversion schemes were introduced.Then outcomes of reducing 1.5 GHz RF signal to 31.25 MHz intermediate frequency(IF)signal by using these three schemes were performed.Finally the characteristics of each scheme and the factors affecting the results of down conversion are analyzed.[Results]The test results shown that three down conversion schemes has good linearity in different dynamic range and met control system specifications.The optimal scheme based on frequency multiplier achieved best performance of linear dynamic range greater than 70 dB and lowest phase noise of IF signal.[Conclusion]A down conversion scheme with frequency multiplier will be applied in the harmonic RF control system.
作者
宫鹏鹏
赵玉彬
侯洪涛
张志刚
郑湘
徐凯
常强
夏洋洋
刘建飞
GONG Pengpeng;ZHAO Yubin;HOU Hongtao;ZHANG Zhigang;ZHENG Xiang;XU Kai;CHANG Qiang;XIAYangyang;LIU Jianfei(Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China;University of Chinese Academy of Sciences,Beijing 100049,China;Shanghai Key Laboratory of Cryogenics&Superconducting RF Technology,Shanghai 201800,China)
出处
《核技术》
CAS
CSCD
北大核心
2019年第1期1-6,共6页
Nuclear Techniques
基金
国家自然科学基金(No.11335014)资助~~
关键词
三次谐波腔
下变频
低电平
托歇克寿命
Third harmonic cavity
Down conversion
Low level radio frequency(LLRF)
Touschek lifetime
