Bunch charge uniformity controlling is very important for top-up operation of the storage ring.In order to monitor filling pattern and measure the bunch charge precisely,a PXI waveform digitizer-based data acquisition...Bunch charge uniformity controlling is very important for top-up operation of the storage ring.In order to monitor filling pattern and measure the bunch charge precisely,a PXI waveform digitizer-based data acquisition system has been developed to retrieve bunch charge information from BPM pickup signals.An effective sampling rate is extended to 400 GHz by waveform rebuilding technology,which overlays multi-turn data into single turn with real time sampling rate of 8 GHz.An on-line evaluation indicates that resolution and linearity of the charge measurement are better than 0.5% at input range of 0.5-12nC.展开更多
A bunch arrival-time monitor(BAM) system,based on electro-optical intensity modulation scheme, is under study at Shanghai Soft X-ray Free Electron Laser.The aim of the study is to achieve high-precision time measureme...A bunch arrival-time monitor(BAM) system,based on electro-optical intensity modulation scheme, is under study at Shanghai Soft X-ray Free Electron Laser.The aim of the study is to achieve high-precision time measurement for minimizing bunch fluctuations. A readout electronics is developed to fulfill the requirements of the BAM system. The readout electronics is mainly composed of a signal conditioning circuit, field-programmable gate array(FPGA), mezzanine card(FMC150), and powerful FPGA carrier board. The signal conditioning circuit converts the laser pulses into electrical pulse signals using a photodiode. Thereafter, it performs splitting and low-noise amplification to achieve the best voltage sampling performance of the dual-channel analog-to-digital converter(ADC) in FMC150. The FMC150 ADC daughter card includes a 14-bit 250 Msps dual-channel high-speed ADC,a clock configuration, and a management module. The powerful FPGA carrier board is a commercial high-performance Xilinx Kintex-7 FPGA evaluation board. To achieve clock and data alignment for ADC data capture at a high sampling rate, we used ISERDES, IDELAY, and dedicated carry-in resources in the Kintex-7 FPGA. This paper presents a detailed development of the readout electronics in the BAM system and its performance.展开更多
A bunch arrival-time monitor(BAM) based on an electro-optical intensity modulation scheme is currently under development at Shanghai Soft X-ray Free-Electron Laser to meet the high-resolution requirements for bunch st...A bunch arrival-time monitor(BAM) based on an electro-optical intensity modulation scheme is currently under development at Shanghai Soft X-ray Free-Electron Laser to meet the high-resolution requirements for bunch stability. The BAM uses a radio frequency signal generated by a pickup cavity to modulate the reference laser pulses in an electro-optical intensity modulator(EOM), and the bunch arrival-time information is derived from the amplitude change of the laser pulse after laser pulse modulation.EOM is a key optical component in the BAM system.Through the basic principle analysis of BAM, many parameters of the EOM are observed to affect the measurement resolution of the BAM system. Therefore, a systematic analysis of the EOM is crucial. In this paper, we present two schemes to compare and analyze an EOM and provide a reference for selecting a new version of the EOM.展开更多
The top-up injection mode of Shanghai Synchrotron Radiation Facility(SSRF) needs precise measurement of the beam bunch charges.This is performed by an integration current transformer,but the beam current is too low to...The top-up injection mode of Shanghai Synchrotron Radiation Facility(SSRF) needs precise measurement of the beam bunch charges.This is performed by an integration current transformer,but the beam current is too low to neglect the background noise.In order to wipe out the noise coming from the ground loops,the adaptable polynomial fitting method is used to extract the baseline,instead of using the constant background or the linear background model. Test results show that the system resolution can be improved to <3%.展开更多
基金Supported by 100 Talents Program of the Chinese Academy of Sciences and national "SSRF project"
文摘Bunch charge uniformity controlling is very important for top-up operation of the storage ring.In order to monitor filling pattern and measure the bunch charge precisely,a PXI waveform digitizer-based data acquisition system has been developed to retrieve bunch charge information from BPM pickup signals.An effective sampling rate is extended to 400 GHz by waveform rebuilding technology,which overlays multi-turn data into single turn with real time sampling rate of 8 GHz.An on-line evaluation indicates that resolution and linearity of the charge measurement are better than 0.5% at input range of 0.5-12nC.
基金supported by the National Key R&D Plan(No.2016YFA0401900)
文摘A bunch arrival-time monitor(BAM) system,based on electro-optical intensity modulation scheme, is under study at Shanghai Soft X-ray Free Electron Laser.The aim of the study is to achieve high-precision time measurement for minimizing bunch fluctuations. A readout electronics is developed to fulfill the requirements of the BAM system. The readout electronics is mainly composed of a signal conditioning circuit, field-programmable gate array(FPGA), mezzanine card(FMC150), and powerful FPGA carrier board. The signal conditioning circuit converts the laser pulses into electrical pulse signals using a photodiode. Thereafter, it performs splitting and low-noise amplification to achieve the best voltage sampling performance of the dual-channel analog-to-digital converter(ADC) in FMC150. The FMC150 ADC daughter card includes a 14-bit 250 Msps dual-channel high-speed ADC,a clock configuration, and a management module. The powerful FPGA carrier board is a commercial high-performance Xilinx Kintex-7 FPGA evaluation board. To achieve clock and data alignment for ADC data capture at a high sampling rate, we used ISERDES, IDELAY, and dedicated carry-in resources in the Kintex-7 FPGA. This paper presents a detailed development of the readout electronics in the BAM system and its performance.
基金supported by the National Key R&D Plan(No.2016YFA0401900)
文摘A bunch arrival-time monitor(BAM) based on an electro-optical intensity modulation scheme is currently under development at Shanghai Soft X-ray Free-Electron Laser to meet the high-resolution requirements for bunch stability. The BAM uses a radio frequency signal generated by a pickup cavity to modulate the reference laser pulses in an electro-optical intensity modulator(EOM), and the bunch arrival-time information is derived from the amplitude change of the laser pulse after laser pulse modulation.EOM is a key optical component in the BAM system.Through the basic principle analysis of BAM, many parameters of the EOM are observed to affect the measurement resolution of the BAM system. Therefore, a systematic analysis of the EOM is crucial. In this paper, we present two schemes to compare and analyze an EOM and provide a reference for selecting a new version of the EOM.
基金Supported by National Natural Science Foundation of China(11075198)
文摘The top-up injection mode of Shanghai Synchrotron Radiation Facility(SSRF) needs precise measurement of the beam bunch charges.This is performed by an integration current transformer,but the beam current is too low to neglect the background noise.In order to wipe out the noise coming from the ground loops,the adaptable polynomial fitting method is used to extract the baseline,instead of using the constant background or the linear background model. Test results show that the system resolution can be improved to <3%.
