A new measurement method for the spatial distribution of neutron beam flux in boron neutron capture therapy(BNCT)is being developed based on the two-dimensional Micromegas detector.To address the issue of long process...A new measurement method for the spatial distribution of neutron beam flux in boron neutron capture therapy(BNCT)is being developed based on the two-dimensional Micromegas detector.To address the issue of long processing times in traditional offline position reconstruction methods,this paper proposes a field programmable gate array based online position reconstruction method utilizing the micro-time projection chamber principle.This method encapsulates key technical aspects:a self-adaptive serial link technique built upon the dynamical adjustment of the delay chain length,fast sorting,a coordinate-matching technique based on the mapping between signal timestamps and random access memory(RAM)addresses,and a precise start point-merging technique utilizing a circular combined RAM.The performance test of the selfadaptive serial link shows that the bit error rate of the link is better than 10-12 at a confidence level of 99%,ensuring reliable data transmission.The experiment utilizing the readout electronics and Micromegas detector shows a spatial resolution of approximately 1.4 mm,surpassing the current method’s resolution level of 5 mm.The beam experiment confirms that the readout electronics system can obtain the flux spatial distribution of neutron beams online,thus validating the feasibility of the position reconstruction method.The online position reconstruction method avoids traditional methods,such as bubble sorting and traversal searching,simplifies the design of the logic firmware,and reduces the time complexity from O(n2)to O(n).This study contributes to the advancement in measuring neutron beam flux for BNCT.展开更多
轴向位置的精确测量是快中子探测领域的挑战和难题,对高分辨率的快中子成像具有重要意义。改进位置和时间响应能使快中子成像获得更好的成像分辨率和对比度,而提升时间分辨的困难主要来自相互作用深度(depth of interaction,DOI)的不确...轴向位置的精确测量是快中子探测领域的挑战和难题,对高分辨率的快中子成像具有重要意义。改进位置和时间响应能使快中子成像获得更好的成像分辨率和对比度,而提升时间分辨的困难主要来自相互作用深度(depth of interaction,DOI)的不确定性。针对位置改进的问题,设计了一种基于有机闪烁体阵列的双端读出快中子探测器,提出了一种用于校准DOI的方法。该校准方法基于快中子探测器双端读出的数据来进行系列计算和拟合,最终得到轴向位置校准曲线。研究结果表明,该校准方法解决了快中子探测中轴向定位不准确的问题,提高了快中子探测器的位置分辨率。展开更多
This work aims at developing compact readout electronics for a compact imaging detector module with silicon photomultiplier （SPM） array. The detector module consists of a LYSO crystal array coupling with a SensL’s ...This work aims at developing compact readout electronics for a compact imaging detector module with silicon photomultiplier （SPM） array. The detector module consists of a LYSO crystal array coupling with a SensL’s 4×4 SPM array. A compact multiplexed readout based on a discretized positioning circuit （DPC） was developed to reduce the readout channels from 16 to 4 outputs. Different LYSO crystal arrays of 4×4, 8×8 and 12×12 with pixel sizes of 3.2, 1.6 and 1.0 mm respectively, have been tested with the compact readout board using a 137 Cs source. The initial results show that the compact imaging detector module with the compact multiplexed readout could clearly resolve 1 mm×1 mm×10 mm LYSO scintillation crystal array except those at the edges. The detector’s intrinsic spatial resolution up to 1 mm can be achieved with the 3 mm×3 mm size SPMArray4 through light sharing and compact multiplexed readout. Our results indicate that this detector module is feasible for the development of high-resolution compact PET.展开更多
Systematic investigations including both simulation and prototype tests have been done about the interpolating resistive readout structure with GEM （Gaseous Electron Multiplier） detector. From the simulation, we hav...Systematic investigations including both simulation and prototype tests have been done about the interpolating resistive readout structure with GEM （Gaseous Electron Multiplier） detector. From the simulation, we have a good knowledge of the process of charge diffusion on the surface of the readout plane and develop several reconstruction methods to determine the hit position. The total signal duration time of a typical event with the readout structure was about several hundred nanoseconds, which implied an ideal count rate up to 106 Hz. A stable working prototype was designed and fabricated after the simulation. Using 55Fe 5.9 performance of the prototype was examined with flat field image and some special geometry energy resolution of about 17% was obtained. keV X-ray, the image shapes, meanwhile, an展开更多
基金supported by the National Natural Science Foundation of China(No.12075237)。
文摘A new measurement method for the spatial distribution of neutron beam flux in boron neutron capture therapy(BNCT)is being developed based on the two-dimensional Micromegas detector.To address the issue of long processing times in traditional offline position reconstruction methods,this paper proposes a field programmable gate array based online position reconstruction method utilizing the micro-time projection chamber principle.This method encapsulates key technical aspects:a self-adaptive serial link technique built upon the dynamical adjustment of the delay chain length,fast sorting,a coordinate-matching technique based on the mapping between signal timestamps and random access memory(RAM)addresses,and a precise start point-merging technique utilizing a circular combined RAM.The performance test of the selfadaptive serial link shows that the bit error rate of the link is better than 10-12 at a confidence level of 99%,ensuring reliable data transmission.The experiment utilizing the readout electronics and Micromegas detector shows a spatial resolution of approximately 1.4 mm,surpassing the current method’s resolution level of 5 mm.The beam experiment confirms that the readout electronics system can obtain the flux spatial distribution of neutron beams online,thus validating the feasibility of the position reconstruction method.The online position reconstruction method avoids traditional methods,such as bubble sorting and traversal searching,simplifies the design of the logic firmware,and reduces the time complexity from O(n2)to O(n).This study contributes to the advancement in measuring neutron beam flux for BNCT.
文摘轴向位置的精确测量是快中子探测领域的挑战和难题,对高分辨率的快中子成像具有重要意义。改进位置和时间响应能使快中子成像获得更好的成像分辨率和对比度,而提升时间分辨的困难主要来自相互作用深度(depth of interaction,DOI)的不确定性。针对位置改进的问题,设计了一种基于有机闪烁体阵列的双端读出快中子探测器,提出了一种用于校准DOI的方法。该校准方法基于快中子探测器双端读出的数据来进行系列计算和拟合,最终得到轴向位置校准曲线。研究结果表明,该校准方法解决了快中子探测中轴向定位不准确的问题,提高了快中子探测器的位置分辨率。
基金Supported by National Natural Science Foundation of China (10875162, 1105209)
文摘This work aims at developing compact readout electronics for a compact imaging detector module with silicon photomultiplier （SPM） array. The detector module consists of a LYSO crystal array coupling with a SensL’s 4×4 SPM array. A compact multiplexed readout based on a discretized positioning circuit （DPC） was developed to reduce the readout channels from 16 to 4 outputs. Different LYSO crystal arrays of 4×4, 8×8 and 12×12 with pixel sizes of 3.2, 1.6 and 1.0 mm respectively, have been tested with the compact readout board using a 137 Cs source. The initial results show that the compact imaging detector module with the compact multiplexed readout could clearly resolve 1 mm×1 mm×10 mm LYSO scintillation crystal array except those at the edges. The detector’s intrinsic spatial resolution up to 1 mm can be achieved with the 3 mm×3 mm size SPMArray4 through light sharing and compact multiplexed readout. Our results indicate that this detector module is feasible for the development of high-resolution compact PET.
基金Innovation Fund for Young Scholars of Institute of High Energy Physics
文摘Systematic investigations including both simulation and prototype tests have been done about the interpolating resistive readout structure with GEM （Gaseous Electron Multiplier） detector. From the simulation, we have a good knowledge of the process of charge diffusion on the surface of the readout plane and develop several reconstruction methods to determine the hit position. The total signal duration time of a typical event with the readout structure was about several hundred nanoseconds, which implied an ideal count rate up to 106 Hz. A stable working prototype was designed and fabricated after the simulation. Using 55Fe 5.9 performance of the prototype was examined with flat field image and some special geometry energy resolution of about 17% was obtained. keV X-ray, the image shapes, meanwhile, an
