Purpose In order to update the BPM electronic in BEPCII,a high-performance digital BPM processor is designed,and the RF front-end electronic is the key part in the digital BPM processor system.Methods According to the...Purpose In order to update the BPM electronic in BEPCII,a high-performance digital BPM processor is designed,and the RF front-end electronic is the key part in the digital BPM processor system.Methods According to the BEPCII physical parameters andADCunder-sampling theorem,the low-noise and high-dynamicrange RF front-end electronic module is designed.This article will introduce filter,RF amplifier,isolation,system test,etc.Results and conclusions The experimental results showed that BPM position short-term resolution is better than 100 nm,and long-term resolution is better than 5μm.It is the first domestic BPM processor that runs stably in the storage ring accelerator for a long time.Meanwhile,the study can help us to establish a solid foundation for the next work of BPM electronics development.展开更多
Background In the linac of Beijing Electron Positron Collider II(BEPCII),the resolution of existing BPMs is several hundred microns.But the requirement of transverse position resolution of BPM for future top-up inject...Background In the linac of Beijing Electron Positron Collider II(BEPCII),the resolution of existing BPMs is several hundred microns.But the requirement of transverse position resolution of BPM for future top-up injection needs to be more precise.Purpose This paper is mainly concerned about the design and simulation of the cavity beam position monitor(CBPM)for BEPCII linac and free electron laser(FEL).The requirement of beam transverse position resolution for linac is several microns,even a few nanometers for FEL.Methods When the beam bunch goes through the CBPM,it can excite different electromagnetic field modes in resonator.In these modes,TM_(110) is the most sensitive to beam transverse position offset.The design of CBPM is aim to analyze the relationship between TM_(110) and beam transverse position by CST Studio and Ansys HFSS.Conclusion In this research,we design a pair of rectangular slots for position cavity to revise the direction of electromagnetic field.The simulation result of theoretical resolution is able to reach 15 nm@1nC with the operating frequency 2500 MHz.It is obviously that CBPM has more excellent resolution than all of operating BPM in BEPCII.Meanwhile,the research of CBPM improves the application of beam detection technology in BEPCII and accumulates technology for future design of HEPS and FEL.The mechanical design of the prototype is being fabricated.展开更多
Background The current strategy to achieve high luminosity for high energy physics experiments is to store huge currents distributed in many bunches in circular machines such as BEPCII,so the longitudinal coupled bunc...Background The current strategy to achieve high luminosity for high energy physics experiments is to store huge currents distributed in many bunches in circular machines such as BEPCII,so the longitudinal coupled bunch instabilities of the beam are inevitable.Purpose Therefore,a longitudinal feedback system is needed to suppress longitudinal oscillation.Otherwise,the beam energy spread will increase;the luminosity and the beam lifetime will decrease under a certain beam current.Methods For filter design of the feedback system,the time domain least square fitting(TDLSF)method is compared to the selective wave filter method;digital signal processing electronics based on commercial board have been developed and tested on BEPCII.Results The final result shows that the self-developed longitudinal feedback system can suppress the longitudinal beam oscillation at 750 mA beam current and meet the requirements of BEPCII;the restrain depth to the sidebands reaches to 40.8 dB.展开更多
基金the National Natural Science Foundation of China(11805221)the Union Foundation of excellent post-doctoral of China Post-Doctoral Science Foundation and Chinese Science Academy(Y71I21)。
文摘Purpose In order to update the BPM electronic in BEPCII,a high-performance digital BPM processor is designed,and the RF front-end electronic is the key part in the digital BPM processor system.Methods According to the BEPCII physical parameters andADCunder-sampling theorem,the low-noise and high-dynamicrange RF front-end electronic module is designed.This article will introduce filter,RF amplifier,isolation,system test,etc.Results and conclusions The experimental results showed that BPM position short-term resolution is better than 100 nm,and long-term resolution is better than 5μm.It is the first domestic BPM processor that runs stably in the storage ring accelerator for a long time.Meanwhile,the study can help us to establish a solid foundation for the next work of BPM electronics development.
基金the Major Projects of the Ministry of Science and Technology(Grant No.2016YFA040190301).
文摘Background In the linac of Beijing Electron Positron Collider II(BEPCII),the resolution of existing BPMs is several hundred microns.But the requirement of transverse position resolution of BPM for future top-up injection needs to be more precise.Purpose This paper is mainly concerned about the design and simulation of the cavity beam position monitor(CBPM)for BEPCII linac and free electron laser(FEL).The requirement of beam transverse position resolution for linac is several microns,even a few nanometers for FEL.Methods When the beam bunch goes through the CBPM,it can excite different electromagnetic field modes in resonator.In these modes,TM_(110) is the most sensitive to beam transverse position offset.The design of CBPM is aim to analyze the relationship between TM_(110) and beam transverse position by CST Studio and Ansys HFSS.Conclusion In this research,we design a pair of rectangular slots for position cavity to revise the direction of electromagnetic field.The simulation result of theoretical resolution is able to reach 15 nm@1nC with the operating frequency 2500 MHz.It is obviously that CBPM has more excellent resolution than all of operating BPM in BEPCII.Meanwhile,the research of CBPM improves the application of beam detection technology in BEPCII and accumulates technology for future design of HEPS and FEL.The mechanical design of the prototype is being fabricated.
文摘Background The current strategy to achieve high luminosity for high energy physics experiments is to store huge currents distributed in many bunches in circular machines such as BEPCII,so the longitudinal coupled bunch instabilities of the beam are inevitable.Purpose Therefore,a longitudinal feedback system is needed to suppress longitudinal oscillation.Otherwise,the beam energy spread will increase;the luminosity and the beam lifetime will decrease under a certain beam current.Methods For filter design of the feedback system,the time domain least square fitting(TDLSF)method is compared to the selective wave filter method;digital signal processing electronics based on commercial board have been developed and tested on BEPCII.Results The final result shows that the self-developed longitudinal feedback system can suppress the longitudinal beam oscillation at 750 mA beam current and meet the requirements of BEPCII;the restrain depth to the sidebands reaches to 40.8 dB.
