上海软X射线自由电子激光装置(Shanghai Soft X-ray Free Electron Laser,SXFEL)需1个分辨率达到亚μm量级的束流位置测量系统,并采用基于束流准直的方法实现波荡器段电子束与光子束的紧密重合。为此设计研制了1个由C波段腔式探头、单...上海软X射线自由电子激光装置(Shanghai Soft X-ray Free Electron Laser,SXFEL)需1个分辨率达到亚μm量级的束流位置测量系统,并采用基于束流准直的方法实现波荡器段电子束与光子束的紧密重合。为此设计研制了1个由C波段腔式探头、单路混频至低中频的射频前端以及自主研发的专用数字信号束流位置处理器(digital beam position monitor processor,DBPM)构成的腔式束流位置测量(cavity beam position monitor,CBPM)系统。本文对系统的设计、软硬件结构、系统搭建进行了介绍,并基于漂移段搭建的3个紧邻的CBPM阵列完成了在线系统性能评估。束流实验结果表明,在束团电荷量为500 pC、系统动态范围在±800μm的条件下,位置分辨率可达880 nm,这也是国内首次研制成功可在线运行的具有亚μm位置分辨率的CBPM系统。此外,采用CBPM的相位腔进行相对束团电荷量、束团到达时间的测量,其性能评估结果也均优于SXFEL设计要求。展开更多
为满足高能同步辐射光源(High Energy Photon Source,HEPS)束流位置测量的需求,研制了各种类型的束流位置探测器(Beam Position Monitor,BPM)。位置灵敏度系数是BPM的一项重要参数,通过它可以精确计算束流的位置。使用边界元法计算束流...为满足高能同步辐射光源(High Energy Photon Source,HEPS)束流位置测量的需求,研制了各种类型的束流位置探测器(Beam Position Monitor,BPM)。位置灵敏度系数是BPM的一项重要参数,通过它可以精确计算束流的位置。使用边界元法计算束流位置探测器的灵敏度系数,适用于在无法使用天线模拟束流进行实际测量和有限元软件进行模拟的场合。以HEPS储存环BPM的参数为例,首先用边界元法分析计算了具有圆形横截面的BPM的位置灵敏度系数,在此基础上,分析了椭圆形(HEPS增强器)与八边形(BEPCⅡ储存环)管道的系数。将该方法应用于BPM的设计与分析中,确定了高能光源增强器BPM纽扣电极的方位角和北京正负电子对撞机BPM的纽扣电极间距。此外,计算了上述BPM的位置灵敏度系数分布Mapping图。圆形管道BPM的位置灵敏度系数结果与解析值接近,相对误差在1%左右,椭圆形与八边形管道BPM的计算结果与实际测量结果的偏差都在2%左右,证明了边界元法计算束流位置探测器的位置灵敏度系数是一种可靠的方法,可用于BPM的设计与相关问题的分析。展开更多
As a third generation light source, Shanghai Synchrotron Radiation Facility (SSRF) has up to 140 beam position monitors (BPM) installed to monitor the beam dynamics on its storage ring. Once the operation mode is chos...As a third generation light source, Shanghai Synchrotron Radiation Facility (SSRF) has up to 140 beam position monitors (BPM) installed to monitor the beam dynamics on its storage ring. Once the operation mode is chosen, the betatron functions are determined. Since the sinusoidal betatron oscillation is the dominant component of the transverse motion, these BPMs can be used to measure the motion to get the betatron functions. Three methods are compared to calculate the phase advance among the BPMs in this paper, aiming to find one or more feasible ways to check the beam optics in SSRF. Some experiments have also been made to verify the practicality of the phase information.展开更多
In this paper,in order to achieve the output signal processing of cavity beam position monitor(CBPM),we develop a digital intermediate frequency receiver architecture based signal processing system,which consists of r...In this paper,in order to achieve the output signal processing of cavity beam position monitor(CBPM),we develop a digital intermediate frequency receiver architecture based signal processing system,which consists of radio frequency(RF) front end and high speed data acquisition board.The beam position resolution in the CBPM signal processing system is superior to 1μm.Two signal processing algorithms,fast Fourier transform(FFT) and digital down converter(DDC),are evaluated offline using MATLAB platform,and both can be used to achieve,the CW input signal,position resolutions of 0.31μm and 0.10μm at -16 dBm.The DDC algorithm for its good compatibility is downloaded into the FPGA to realize online measurement,reaching the position resolution of 0.49μm due to truncation error.The whole system works well and the performance meets design target.展开更多
In order to suppress multi-bunch couple instabilities caused by transverse impedance, a bunch-by-bunch transverse feedback system based on a FPGA digital processor is commissioned at SSRF storage ring. The RF front en...In order to suppress multi-bunch couple instabilities caused by transverse impedance, a bunch-by-bunch transverse feedback system based on a FPGA digital processor is commissioned at SSRF storage ring. The RF front end has two COD pre-rejected attenuators for increasing the system arrangement and signal noise ratio, and the 3*RF Local signal comes from the BPM's sum signal using a FIR filter for avoiding the effect of longitudinal oscillation. The digital processor receives the coupled horizontal and vertical oscillation signals in the base band and transforms the coupled signals to the horizontal and vertical feedback signals with two series double-zeroes FIR filters. A matlab GUI is applied for producing the FIR coefficients when the tune is shifted. The horizontal and vertical Kickers have a special design for increasing the shunt impedance. Then the multi-bunch instabilities are suppressed respectively and the minimum damping time is about 0.4 ms.展开更多
文摘上海软X射线自由电子激光装置(Shanghai Soft X-ray Free Electron Laser,SXFEL)需1个分辨率达到亚μm量级的束流位置测量系统,并采用基于束流准直的方法实现波荡器段电子束与光子束的紧密重合。为此设计研制了1个由C波段腔式探头、单路混频至低中频的射频前端以及自主研发的专用数字信号束流位置处理器(digital beam position monitor processor,DBPM)构成的腔式束流位置测量(cavity beam position monitor,CBPM)系统。本文对系统的设计、软硬件结构、系统搭建进行了介绍,并基于漂移段搭建的3个紧邻的CBPM阵列完成了在线系统性能评估。束流实验结果表明,在束团电荷量为500 pC、系统动态范围在±800μm的条件下,位置分辨率可达880 nm,这也是国内首次研制成功可在线运行的具有亚μm位置分辨率的CBPM系统。此外,采用CBPM的相位腔进行相对束团电荷量、束团到达时间的测量,其性能评估结果也均优于SXFEL设计要求。
文摘为满足高能同步辐射光源(High Energy Photon Source,HEPS)束流位置测量的需求,研制了各种类型的束流位置探测器(Beam Position Monitor,BPM)。位置灵敏度系数是BPM的一项重要参数,通过它可以精确计算束流的位置。使用边界元法计算束流位置探测器的灵敏度系数,适用于在无法使用天线模拟束流进行实际测量和有限元软件进行模拟的场合。以HEPS储存环BPM的参数为例,首先用边界元法分析计算了具有圆形横截面的BPM的位置灵敏度系数,在此基础上,分析了椭圆形(HEPS增强器)与八边形(BEPCⅡ储存环)管道的系数。将该方法应用于BPM的设计与分析中,确定了高能光源增强器BPM纽扣电极的方位角和北京正负电子对撞机BPM的纽扣电极间距。此外,计算了上述BPM的位置灵敏度系数分布Mapping图。圆形管道BPM的位置灵敏度系数结果与解析值接近,相对误差在1%左右,椭圆形与八边形管道BPM的计算结果与实际测量结果的偏差都在2%左右,证明了边界元法计算束流位置探测器的位置灵敏度系数是一种可靠的方法,可用于BPM的设计与相关问题的分析。
基金Supported by National Natural Science Foundation of China (No.11075198)
文摘As a third generation light source, Shanghai Synchrotron Radiation Facility (SSRF) has up to 140 beam position monitors (BPM) installed to monitor the beam dynamics on its storage ring. Once the operation mode is chosen, the betatron functions are determined. Since the sinusoidal betatron oscillation is the dominant component of the transverse motion, these BPMs can be used to measure the motion to get the betatron functions. Three methods are compared to calculate the phase advance among the BPMs in this paper, aiming to find one or more feasible ways to check the beam optics in SSRF. Some experiments have also been made to verify the practicality of the phase information.
基金Supported by National Natural Science Foundaion of China(No.11075198)
文摘In this paper,in order to achieve the output signal processing of cavity beam position monitor(CBPM),we develop a digital intermediate frequency receiver architecture based signal processing system,which consists of radio frequency(RF) front end and high speed data acquisition board.The beam position resolution in the CBPM signal processing system is superior to 1μm.Two signal processing algorithms,fast Fourier transform(FFT) and digital down converter(DDC),are evaluated offline using MATLAB platform,and both can be used to achieve,the CW input signal,position resolutions of 0.31μm and 0.10μm at -16 dBm.The DDC algorithm for its good compatibility is downloaded into the FPGA to realize online measurement,reaching the position resolution of 0.49μm due to truncation error.The whole system works well and the performance meets design target.
文摘In order to suppress multi-bunch couple instabilities caused by transverse impedance, a bunch-by-bunch transverse feedback system based on a FPGA digital processor is commissioned at SSRF storage ring. The RF front end has two COD pre-rejected attenuators for increasing the system arrangement and signal noise ratio, and the 3*RF Local signal comes from the BPM's sum signal using a FIR filter for avoiding the effect of longitudinal oscillation. The digital processor receives the coupled horizontal and vertical oscillation signals in the base band and transforms the coupled signals to the horizontal and vertical feedback signals with two series double-zeroes FIR filters. A matlab GUI is applied for producing the FIR coefficients when the tune is shifted. The horizontal and vertical Kickers have a special design for increasing the shunt impedance. Then the multi-bunch instabilities are suppressed respectively and the minimum damping time is about 0.4 ms.
