近年来应用于中高能核物理实验的先进前端读出专用集成电路(application specific integrated circuit,ASIC)芯片呈现出越来越强的数字化趋势,可提高系统的集成度并降低功耗。论文研制了一种高计数率多通道时间测量与串行读出电路(high-...近年来应用于中高能核物理实验的先进前端读出专用集成电路(application specific integrated circuit,ASIC)芯片呈现出越来越强的数字化趋势,可提高系统的集成度并降低功耗。论文研制了一种高计数率多通道时间测量与串行读出电路(high-count rate multi-channel time measurement and serial readout circuit,HMTRC),可实现核事件去稀疏化、去随机化的读出。该电路主要包括了基于时钟分相技术的时间数字转化器、控制器、先进先出存储器和基于令牌环逻辑的轮询读出模块。HMTRC已被集成到一款自研的16通道前端读出ASIC芯片中,可测量和储存时间信息,并利用数字驱动的前端读出架构实现时间与能量信息同步读出。测试表明,时间分辨率好于2 ns,功能符合预期。展开更多
The High-energy Fragment Separator(HFRS),which is currently under construction,is a leading international radioactive beam device.Multiple sets of position-sensitive twin time projection chamber(TPC)detectors are dist...The High-energy Fragment Separator(HFRS),which is currently under construction,is a leading international radioactive beam device.Multiple sets of position-sensitive twin time projection chamber(TPC)detectors are distributed on HFRS for particle identification and beam monitoring.The twin TPCs'readout electronics system operates in a trigger-less mode due to its high counting rate,leading to a challenge of handling large amounts of data.To address this problem,we introduced an event-building algorithm.This algorithm employs a hierarchical processing strategy to compress data during transmission and aggregation.In addition,it reconstructs twin TPCs'events online and stores only the reconstructed particle information,which significantly reduces the burden on data transmission and storage resources.Simulation studies demonstrated that the algorithm accurately matches twin TPCs'events and reduces more than 98%of the data volume at a counting rate of 500 kHz/channel.展开更多
A passive neutron multiplicity measurement device,FH-NCM/S1,based on field-programmable gate arrays(FPGAs),is developed specifically for measuring the mass of plutonium-240(^(240)Pu)in mixed oxide fuel.FH-NCM/S1 adopt...A passive neutron multiplicity measurement device,FH-NCM/S1,based on field-programmable gate arrays(FPGAs),is developed specifically for measuring the mass of plutonium-240(^(240)Pu)in mixed oxide fuel.FH-NCM/S1 adopts an inte-grated approach,combining the shift register analysis mode with the pulse-position timestamp mode using an FPGA.The optimal effective length of the^(3)He neutron detector was determined to be 30 cm,and the thickness of the graphite reflector was ascertained to be 15 cm through MCNP simulations.After fabricating the device,calibration measurements were per-formed using a^(252)Cf neutron source;a detection efficiency of 43.07%and detector die-away time of 55.79μs were observed.Nine samples of plutonium oxide were measured under identical conditions using the FH-NCM/S1 in shift register analysis mode and a plutonium waste multiplicity counter.The obtained double rates underwent corrections for detection efficiency(ε)and double gate fraction(f_(d)),resulting in corrected double rates(D_(c)),which were used to validate the accuracy of the shift register analysis mode.Furthermore,the device exhibited fluctuations in the measurement results,and within a single 20 s measurement,these fluctuations remained below 10%.After 30 cycles,the relative error in the mass of^(240)Pu was less than 5%.Finally,correlation calculations confirmed the robust consistency of both measurement modes.This study holds specific significance for the subsequent design and development of neutron multiplicity devices.展开更多
准确获取脉冲能量信息在原子能核技术领域至关重要,现有脉冲能量表征方法中,多电压阈值(multiple voltage thresholds,MVT)采样方法通过引入脉冲信号的先验信息,结合过阈值时间信息,可在不对脉冲信号进行额外硬件处理的情况下完成波形...准确获取脉冲能量信息在原子能核技术领域至关重要,现有脉冲能量表征方法中,多电压阈值(multiple voltage thresholds,MVT)采样方法通过引入脉冲信号的先验信息,结合过阈值时间信息,可在不对脉冲信号进行额外硬件处理的情况下完成波形重建进而获得能量信息,其具有较高的计数率,目前已成功应用于石油测井、医疗成像等领域。然而现有的MVT采样方法在时间采样的实现过程中,每路阈值均需一路独立的时间数字转换(time-to-digital converter,TDC)单元;而一路TDC所需要的硬件资源较多,在多通道场景下其带来的功耗和成本为系统的搭建引入挑战。为此,本文提出了一种低资源消耗型能量表征方法REMVT(resource efficient MVT)。REMVT利用不同阈值被触发的时间不同,且有严格的先后顺序这一特点,将时间信息通过一条TDC链记录,不同阈值对应的触发信号被连到一个组合电路。该组合电路消耗极少的硬件资源,能在每个触发信号到来时将信号电平翻转。通过这种方式,不同阈值下的触发时间与信号的边沿一一对应。通过解调这些信号边沿的间隔即可完成波形重建或能量表征。通过这种时间复用链技术,极大降低资源的消耗,如在4/8阈值的配置中,资源消耗将降低75%/87.5%。另外,这种时间复用链技术降低了原来采用多链时的差异性,使得时间测量的抖动减小,因而波形重建的效果更优。相比MVT,该技术在使用更少资源的条件下将脉冲能量表征误差在20.5%内的事件占比由72%提升至79%;通过该技术,在正电子发射断层成像场景中进行了测试,获得了13.2%@511 keV的能量分辨率,与高采样率通用示波器的能量表征结果相比,仅1.1%的差距。此外,本文提出了一种针对REMVT的事件检测与脉冲堆叠还原算法。该算法充分利用脉冲信号的先验信息,即不同阈值被触发的先后顺序与时间间隔来完成对脉冲事件的可靠检测与堆叠事件的准确还原。实验结果表明,93%的脉冲堆叠事件被完整还原。展开更多
文摘近年来应用于中高能核物理实验的先进前端读出专用集成电路(application specific integrated circuit,ASIC)芯片呈现出越来越强的数字化趋势,可提高系统的集成度并降低功耗。论文研制了一种高计数率多通道时间测量与串行读出电路(high-count rate multi-channel time measurement and serial readout circuit,HMTRC),可实现核事件去稀疏化、去随机化的读出。该电路主要包括了基于时钟分相技术的时间数字转化器、控制器、先进先出存储器和基于令牌环逻辑的轮询读出模块。HMTRC已被集成到一款自研的16通道前端读出ASIC芯片中,可测量和储存时间信息,并利用数字驱动的前端读出架构实现时间与能量信息同步读出。测试表明,时间分辨率好于2 ns,功能符合预期。
基金partially supported by the Strategic Priority Research Program of Chinese Academy of Science(No.XDB 34030000)the National Natural Science Foundation of China(Nos.11975293 and 12205348)。
文摘The High-energy Fragment Separator(HFRS),which is currently under construction,is a leading international radioactive beam device.Multiple sets of position-sensitive twin time projection chamber(TPC)detectors are distributed on HFRS for particle identification and beam monitoring.The twin TPCs'readout electronics system operates in a trigger-less mode due to its high counting rate,leading to a challenge of handling large amounts of data.To address this problem,we introduced an event-building algorithm.This algorithm employs a hierarchical processing strategy to compress data during transmission and aggregation.In addition,it reconstructs twin TPCs'events online and stores only the reconstructed particle information,which significantly reduces the burden on data transmission and storage resources.Simulation studies demonstrated that the algorithm accurately matches twin TPCs'events and reduces more than 98%of the data volume at a counting rate of 500 kHz/channel.
基金supported by the National Natural Science Foundation of China(No.42374226)Natural Science Foundation of Jiangxi Province(Nos.20232BAB201043 and 20232BCJ23006)+1 种基金a sub-project of the nuclear energy development project of the China National Defense Science and Industry Bureau‘n-γfusion logging method theory research’(No.20201192-01)the Fundamental Science on Radioactive Geology and Exploration Technology Laboratory(No.2022RGET20)。
文摘A passive neutron multiplicity measurement device,FH-NCM/S1,based on field-programmable gate arrays(FPGAs),is developed specifically for measuring the mass of plutonium-240(^(240)Pu)in mixed oxide fuel.FH-NCM/S1 adopts an inte-grated approach,combining the shift register analysis mode with the pulse-position timestamp mode using an FPGA.The optimal effective length of the^(3)He neutron detector was determined to be 30 cm,and the thickness of the graphite reflector was ascertained to be 15 cm through MCNP simulations.After fabricating the device,calibration measurements were per-formed using a^(252)Cf neutron source;a detection efficiency of 43.07%and detector die-away time of 55.79μs were observed.Nine samples of plutonium oxide were measured under identical conditions using the FH-NCM/S1 in shift register analysis mode and a plutonium waste multiplicity counter.The obtained double rates underwent corrections for detection efficiency(ε)and double gate fraction(f_(d)),resulting in corrected double rates(D_(c)),which were used to validate the accuracy of the shift register analysis mode.Furthermore,the device exhibited fluctuations in the measurement results,and within a single 20 s measurement,these fluctuations remained below 10%.After 30 cycles,the relative error in the mass of^(240)Pu was less than 5%.Finally,correlation calculations confirmed the robust consistency of both measurement modes.This study holds specific significance for the subsequent design and development of neutron multiplicity devices.
