高海拔宇宙线观测站(Large High Altitude Air Shower Observatory,LHAASO)是"十二五"批复立项的国家重大科技基础设施,是我国海拔最高的大科学基础设施之一,核心目标是探索高能宇宙线。作为LHAASO的重要组成,地面簇射粒子阵...高海拔宇宙线观测站(Large High Altitude Air Shower Observatory,LHAASO)是"十二五"批复立项的国家重大科技基础设施,是我国海拔最高的大科学基础设施之一,核心目标是探索高能宇宙线。作为LHAASO的重要组成,地面簇射粒子阵列(square KiloMeter detector Array,KM2A)建成探测阵列面积高达1 km^2。不同于大多高能物理实验,KM2A共约6 500路通道,总输入约546 MB·s^(-1),没有硬件触发功能,因此,需要软件完成触发与数据处理。采用基于标准以太网和TCP/IP协议的数据传输方案,接收包括所有探测器单元同一时间的全部组包数据,利用配置的触发算法对数据包进行在线处理与计算,将具有物理意义的数据提取、打包,组成不同的有物理标签的事例,并按照配置的输出规则将这些事例送出至不同的接收方,实现了实时分布式算法调度与数据处理。软件可以实时触发筛选,降低数据量,减轻传输与存储的负担。软件已在4 410 m海拔实验现场的数据中心投入使用,至今为止一直运行良好。展开更多
Purpose Back-n is a white neutron beamline at China spallation neutron source,which was established in the year of 2018.It is a powerful facility for nuclear data measurement,neutron detector calibration,and radiation...Purpose Back-n is a white neutron beamline at China spallation neutron source,which was established in the year of 2018.It is a powerful facility for nuclear data measurement,neutron detector calibration,and radiation effect research.Method A series of detectors were built for different experiments,including beam monitoring,beam profile measurement,neutron induced secondaries(fission fragments,light charged particles and gamma)cross section measurement,and neutron resonance radiography,etc.A common digitization electronics and a cluster-based DAQ were developed for these detector systems.Most detectors have been employed at Back-n and serviced for experiments from the beginning of the beamline running.Results and conclusion As an overview of detectors of Back-n,the details of the detector design and the experiment performing are described in this paper.Some developing systems,e.g.,MTPC and B-MCP,are also included.展开更多
An in-situ polymerization method was employed to synthesize the nanosilica/acrylic/epoxy (SAE) hybrid coating on AISI 430 stainless steel (430SS), as compared with a traditional blending method. Mi- crostructures of t...An in-situ polymerization method was employed to synthesize the nanosilica/acrylic/epoxy (SAE) hybrid coating on AISI 430 stainless steel (430SS), as compared with a traditional blending method. Mi- crostructures of the blending SAE hybrid coating (BC) and in-situ SAE hybrid coating (ISC) were characterized by transmission electron microscopy (TEM). Corrosion resistance of BC and ISC on 430SS was evaluated by the neutral salt spray test and potentiodynamic polarization technique. Failure mechanism of the BC on 430SS was suggested by the microstructures and corrosion behaviors. Serious aggregation of nanosilica particles in the BC impairs its structural uniformity and induces the flaws formation. These flaws in the BC initiates the failures of pitting, filiform corrosion and peeling which are accelerated by the O2 concentration cell and H+ self-catalysis in chlorine-containing moist environments. The ISC-coated 430SS shows a more advantageous corrosion resistance than that of the BC-coated. The ISC-coated 430SS can suffer the salt spray over 1000 h. Besides, it exhibits a high corrosion potential beyond 0.925 V and good passivation characteristics during the potentiodynamic polarization.展开更多
文摘高海拔宇宙线观测站(Large High Altitude Air Shower Observatory,LHAASO)是"十二五"批复立项的国家重大科技基础设施,是我国海拔最高的大科学基础设施之一,核心目标是探索高能宇宙线。作为LHAASO的重要组成,地面簇射粒子阵列(square KiloMeter detector Array,KM2A)建成探测阵列面积高达1 km^2。不同于大多高能物理实验,KM2A共约6 500路通道,总输入约546 MB·s^(-1),没有硬件触发功能,因此,需要软件完成触发与数据处理。采用基于标准以太网和TCP/IP协议的数据传输方案,接收包括所有探测器单元同一时间的全部组包数据,利用配置的触发算法对数据包进行在线处理与计算,将具有物理意义的数据提取、打包,组成不同的有物理标签的事例,并按照配置的输出规则将这些事例送出至不同的接收方,实现了实时分布式算法调度与数据处理。软件可以实时触发筛选,降低数据量,减轻传输与存储的负担。软件已在4 410 m海拔实验现场的数据中心投入使用,至今为止一直运行良好。
基金support provided by the National KeyR&DProgram of China(Grant No.2016YFA0401600).
文摘Purpose Back-n is a white neutron beamline at China spallation neutron source,which was established in the year of 2018.It is a powerful facility for nuclear data measurement,neutron detector calibration,and radiation effect research.Method A series of detectors were built for different experiments,including beam monitoring,beam profile measurement,neutron induced secondaries(fission fragments,light charged particles and gamma)cross section measurement,and neutron resonance radiography,etc.A common digitization electronics and a cluster-based DAQ were developed for these detector systems.Most detectors have been employed at Back-n and serviced for experiments from the beginning of the beamline running.Results and conclusion As an overview of detectors of Back-n,the details of the detector design and the experiment performing are described in this paper.Some developing systems,e.g.,MTPC and B-MCP,are also included.
基金Supported by the National Basic Research Program of China ("973" Program) (Grant No. 2004CB619305) the National Natural Science Foundation of China (Grant No. 50571044)
文摘An in-situ polymerization method was employed to synthesize the nanosilica/acrylic/epoxy (SAE) hybrid coating on AISI 430 stainless steel (430SS), as compared with a traditional blending method. Mi- crostructures of the blending SAE hybrid coating (BC) and in-situ SAE hybrid coating (ISC) were characterized by transmission electron microscopy (TEM). Corrosion resistance of BC and ISC on 430SS was evaluated by the neutral salt spray test and potentiodynamic polarization technique. Failure mechanism of the BC on 430SS was suggested by the microstructures and corrosion behaviors. Serious aggregation of nanosilica particles in the BC impairs its structural uniformity and induces the flaws formation. These flaws in the BC initiates the failures of pitting, filiform corrosion and peeling which are accelerated by the O2 concentration cell and H+ self-catalysis in chlorine-containing moist environments. The ISC-coated 430SS shows a more advantageous corrosion resistance than that of the BC-coated. The ISC-coated 430SS can suffer the salt spray over 1000 h. Besides, it exhibits a high corrosion potential beyond 0.925 V and good passivation characteristics during the potentiodynamic polarization.
