BEPCⅡ储存环束团流强测量

Bunch current measurement system for BEPCⅡ storage ring

针对北京正负电子对撞机二期工程(BEPCⅡ)原束团流强测量系统(BCM)不能稳定运行的问题,对系统进行了升级。利用高速ADC对束流位置探头(BPM)信号直接采样,在现场可编程门阵列(FPGA)内进行实时数字信号处理,进而得到加速器储存环内的束团流强值。基于反射内存网络,系统可以实现测量结果高速共享、实时显示。升级后系统实现了更高精度的测量,实时显示精度到0.1mA,最佳测量精度达到10μA。通过对系统的触发时钟和算法结构调整,系统实现了长时间的稳定工作,正负电子储存环均实现了对束团流强的均匀性控制,提高了加速器的对撞亮度。

The BCM（Bunch Current Measurement）system was developed at BEPCⅡ（Beijing Electron-Positron ColliderⅡ）for solving the instability.In order to measure the bunch current in accelerator storage rings,the signal of beam position monitor（BPM）was sampled by the high-speed ADC,and the digital signal was processed in field-programmable gate array（FPGA）.Based on the reflective memory network,the system realized sharing of the results in high-speed and displayed the results in real-time.The system achieved higher precision,the accuracy of real-time display was 0.1mA/bucket,and the best measurement resolution reached 10μA/bucket.Since the trigger and the algorithm structure for system were adjusted,the system realized stably work for a long time,the positron and the negative electron storage ring could control the uniformity of the bunch current,which improved the luminance of accelerator collisions.