In this paper,a digitalizing board for readout of PMT signals in the prototype array of WCDA(water Cerenkov detector array)for LHAASO(Large high altitude air shower observatory)is designed.The prototype array is compo...In this paper,a digitalizing board for readout of PMT signals in the prototype array of WCDA(water Cerenkov detector array)for LHAASO(Large high altitude air shower observatory)is designed.The prototype array is composed of 9 PMTs,including the pulse time and charge measurement from the PMTs,and clock generation and trigger decision.In the digitalizing board,FPGA reconfiguration and data readout via VME bus are implemented.Test results show that the performances meet well with the requirements of readout electronics.It has been installed in Yangbajing and tests with the prototype array and DAQ is ongoing.展开更多
This fully digital beam position measurement instrument is designed for beam position monitoring and machine research in Shanghai Synchrotron Radiation Facility. The signals received from four position-sensitive detec...This fully digital beam position measurement instrument is designed for beam position monitoring and machine research in Shanghai Synchrotron Radiation Facility. The signals received from four position-sensitive detectors are narrow pulses with a repetition rate up to 499.654 MHz and a pulse width of around 100 ps, and their dynamic range could vary over more than 40 dB in machine research. By the employment of the under-sampling technique based on high-speed high-resolution A/D conversion, all the processing procedure is performed fully by the digital signal processing algorithms integrated in one single Field Programmable Gate Array. This system functions well in the laboratory and commissioning tests, demonstrating a position resolution (at the turn by turn rate of 694 kHz) better than 7 μm over the input amplitude range of -40 dBm to 10 dBm which is well beyond the requirement.展开更多
The architecture of carry chains in Field-Programmable Gate Array(FPGA) is introduced in this paper. The propagation delay time of the rising and falling edges in the carry chains are calculated according to the archi...The architecture of carry chains in Field-Programmable Gate Array(FPGA) is introduced in this paper. The propagation delay time of the rising and falling edges in the carry chains are calculated according to the architecture and they are predicted not equal in most cases. Tests show that the measuring results of the propagation delay time in EP3C120F484C8 N series FPGA of Altera are in line with the inference. The difference of propagation delay time results in different accuracies of Time-to-Digital Converter(TDC). This phenomenon shall be considered in the design of TDC implemented in FPGA. It can ensure better accuracy.展开更多
Due to the large scale of Water Cherenkov Detector Array in Large High Altitude Air Shower Observatory, the frontend digitization is imperative.Thus a clock distribution system is desired,which broadcasts the synchron...Due to the large scale of Water Cherenkov Detector Array in Large High Altitude Air Shower Observatory, the frontend digitization is imperative.Thus a clock distribution system is desired,which broadcasts the synchronous clock signals with low jitter to the frontend electronics distributed in the field of 90 000 m^2.The White Rabbit protocol provides an option,which has been approved to achieve sub-ns accuracy and ps jitter in the synchronization of around 1 000 nodes in the order of 10 km.But the hierarchy of the original is too complex for Large High Altitude Air Shower Observatory application.Thus we proposed a reduced scheme based on the White Rabbit protocol.The validation circuit shows that the clock skew due to the fiber length difference can be adjusted to less than 25 ps and the clock jitter is less than 62 ps.展开更多
In this paper a fast digital real-time spectrometer was developed for timing and analysis of nuclear pulse signals. The hardware system design and algorithm implementation with field-programming gate array （FPGA） an...In this paper a fast digital real-time spectrometer was developed for timing and analysis of nuclear pulse signals. The hardware system design and algorithm implementation with field-programming gate array （FPGA） and digital signal processor （DSP） were introduced. The performance of the digital constant fraction discrimination （dCFD） platform was experimentally tested with Agilent 80 MHz function/arbitrary waveform generator and LaC13：Ce3＋ scintillator detector for 22Na positron annihilation gamma spectroscopy. The amplitude and time information of ＂/photon was online obtained. The energy resolution could be 5.525% and the timing resolution 293.75 ps, the system error estimation of dCFD approach was also studied. The results showed that this spectrometer achieved a timing resolution close to that of traditional CFD timing resolution with a more sim- plified system structure.展开更多
基金Supported by Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.KJCX2-YW-N31)
文摘In this paper,a digitalizing board for readout of PMT signals in the prototype array of WCDA(water Cerenkov detector array)for LHAASO(Large high altitude air shower observatory)is designed.The prototype array is composed of 9 PMTs,including the pulse time and charge measurement from the PMTs,and clock generation and trigger decision.In the digitalizing board,FPGA reconfiguration and data readout via VME bus are implemented.Test results show that the performances meet well with the requirements of readout electronics.It has been installed in Yangbajing and tests with the prototype array and DAQ is ongoing.
基金Supported by Knowledge Innovation Program of The Chinese Academy of Sciences (KJCX2-YW-N27)the National Natural Science Foundation of China (10875119)100 Talents Program of The Chinese Academy of Sciences
文摘This fully digital beam position measurement instrument is designed for beam position monitoring and machine research in Shanghai Synchrotron Radiation Facility. The signals received from four position-sensitive detectors are narrow pulses with a repetition rate up to 499.654 MHz and a pulse width of around 100 ps, and their dynamic range could vary over more than 40 dB in machine research. By the employment of the under-sampling technique based on high-speed high-resolution A/D conversion, all the processing procedure is performed fully by the digital signal processing algorithms integrated in one single Field Programmable Gate Array. This system functions well in the laboratory and commissioning tests, demonstrating a position resolution (at the turn by turn rate of 694 kHz) better than 7 μm over the input amplitude range of -40 dBm to 10 dBm which is well beyond the requirement.
文摘The architecture of carry chains in Field-Programmable Gate Array(FPGA) is introduced in this paper. The propagation delay time of the rising and falling edges in the carry chains are calculated according to the architecture and they are predicted not equal in most cases. Tests show that the measuring results of the propagation delay time in EP3C120F484C8 N series FPGA of Altera are in line with the inference. The difference of propagation delay time results in different accuracies of Time-to-Digital Converter(TDC). This phenomenon shall be considered in the design of TDC implemented in FPGA. It can ensure better accuracy.
基金Supported by the National Natural Science Foundation of China(No.11175174 and No.11005107)the Knowledge Innovation Program of the Chinese Academy of Sciences(KJCX2-YW-N27)
文摘Due to the large scale of Water Cherenkov Detector Array in Large High Altitude Air Shower Observatory, the frontend digitization is imperative.Thus a clock distribution system is desired,which broadcasts the synchronous clock signals with low jitter to the frontend electronics distributed in the field of 90 000 m^2.The White Rabbit protocol provides an option,which has been approved to achieve sub-ns accuracy and ps jitter in the synchronization of around 1 000 nodes in the order of 10 km.But the hierarchy of the original is too complex for Large High Altitude Air Shower Observatory application.Thus we proposed a reduced scheme based on the White Rabbit protocol.The validation circuit shows that the clock skew due to the fiber length difference can be adjusted to less than 25 ps and the clock jitter is less than 62 ps.
基金supported by the National Natural Science Foundation of China (Grant No. 10975132)
文摘In this paper a fast digital real-time spectrometer was developed for timing and analysis of nuclear pulse signals. The hardware system design and algorithm implementation with field-programming gate array （FPGA） and digital signal processor （DSP） were introduced. The performance of the digital constant fraction discrimination （dCFD） platform was experimentally tested with Agilent 80 MHz function/arbitrary waveform generator and LaC13：Ce3＋ scintillator detector for 22Na positron annihilation gamma spectroscopy. The amplitude and time information of ＂/photon was online obtained. The energy resolution could be 5.525% and the timing resolution 293.75 ps, the system error estimation of dCFD approach was also studied. The results showed that this spectrometer achieved a timing resolution close to that of traditional CFD timing resolution with a more sim- plified system structure.
