Trigger System of the NUCLEON Experiment

Physics of Particles and Nuclei Letters - The NUCLEON experiment is aimed at measuring the spectrum and the elemental composition of cosmic rays (CR) in the 1011–1015 eV energy range. The...     

Trigger System of the NUCLEON Space Experiment

The NUCLEON satellite experiment is designed to investigate directly the energy spectra of galactic cosmic ray (CR) nuclei and its charge composition before the “knee”: in the energy interval from 100 GeV to 100 TeV and the charge range Z = 1–30 respectively. The “knee” energy range of 10¹¹–10¹⁶ eV is a crucial region for the understanding of the cosmic-ray acceleration and propagation in the interstellar medium. The NUCLEON detector has been data taken since December, 2014. The NUCLEON trigger system and CR event selection are described, including the beam tests at the SPS CERN, flight tests in orbit and the Monte-Carlo simulation.

     

Time-of-Flight System of HyperNIS Spectrometer

Physics of Particles and Nuclei Letters - The main goal of the HyperNIS experiment is the search for the lightest neutron-rich hypernuclei, in particular, $$_{{\Lambda }}^{{\text{6}}}{\text{H}}$$...     

High Level Trigger System for the ALICE Experiment

The ALICE experiment [1] at the Large Hadron Collider(LHC) at CERN will detect up to 20,000 particles in a single Pb-Pb event resulting in a data rate of -75 MByte/event,The event rate is limited by the bandwidth of the data storage system.Higher rates are possible by selecting interesting events and subevents (High Level trigger) or compressing the data efficiently with modeling techniques.Both require a fast parallel pattern recognition.One possible solution to process the detector data at such rates is a farm of clustered SMP nodes,based on off-the-shelf PCs,and connected by a high bandwidt,low latency network.     

L3宇宙线实验触发系统和触发效率的测量

介绍了在欧洲核子研究中心(CERN)的L3探测器上进行的宇宙线实验的触发系统判选过程,还介绍了使用蒙特卡洛模拟检验触发系统和计算触发效率的方法,并给出了实际数据的测量结果和误差.结果已用于L3宇宙线实验的μ谱的测量中.     

Introduction of the Trigger System and the Measurement for Trigger Efficiency at L3+Cosmics Experiment

The trigger process of L3+Cosmics experiment at CERN is introduced briefly. Also we checked whether the settings of L3+Cosmics trigger system by simulation are correct or not and introduced a method on trigger efficiency calculation. To get trigger efficiency for μ spectrum measurement, an experimental data sample, which includes events passing the trigger set to measure the μ spectrum and not passing, is needed. Then L?3+C trigger process is simulated with these events in this sample to know how many events should pass the trigger. By checking a trigger bit recorded in the experimental data, one can know how many events passed the trigger in hardware in these simulated events. The ratio then determines the trigger efficiency for μ spectrum measurement. And the systematic error is analyzed. The results on trigger efficiency have been used to the measurement of μ spectrum.     

R值扫描实验中触发效率的测量

介绍了北京正负电子对撞机(BEPC)/北京谱仪(BES)R值扫描实验中触发效率的测量方法,BES触发判选系统触发条件表的设置,给出了R值测量实验期间各触发条件、触发道以及不同类型事例的触发效率.     

一种精密触发定时系统

提出并研制了一种精密触发定时系统.它主要利用多个光电倍增管和闪烁体组成的探测系统,对同一事件的时间信息进行多次测量.通过对多个时间信息的离线处理,来获得时间分辨为57ps的精密触发定时系统.该系统可以用于快时间探测器性能的研究.     

LHC能区ALICE实验及其PHOS触发选判

综述了CERN/LHC能区的大型重离子碰撞实验(ALICE)的现状, 并对ALICE实验中的光子谱仪(PHOS)的触发选判机制进行了模拟研究.     

ALICE实验中光子谱仪的触发选判机制的模拟研究

对ALICE实验光子谱仪的触发选判机制进行了模拟研究, 内容包括: 1) 对光子谱仪的能量重建性能进行了研究, 通过计算机模拟检验光子谱仪探测器对大横动量范围的入射粒子的能量重建性能; 2) 对光子谱仪探测器的事件触发效率进行了研究, 通过计算机模拟分析触发阈值的选取并计算触发效率; 3) 对光子谱仪探测器的事件触发频率进行了研究, 通过计算机模拟对p-p和Pb-Pb两种碰撞模式下的触发频率分别进行了估算和讨论.     

BESⅢ触发系统MDC子系统的物理设计

介绍北京谱仪BESⅢ触发系统MDC子系统的物理设计. 该设计根据BESⅢ的物理研究目标,用软件模拟的方法研究了不同触发方案的可行性,并优化了触发参数. 对触发方案的效率进行了仔细研究,给出一些重要反应道的触发效率和本底事例率.     

Specification and Simulation of the ALICE Trigger and DAQ System

The ALICE Trigger and Data Acquisition (TRG/DAQ) System is required to support an aggregate event building bandwidth of up to 4 GByte/s and a storage capability of up to 1.25 GByte/s to mass storage.The system has been decomposed in a set of hardware and software components and prototypes of these components are being developed.It is necessary to verity the system design,its capability to reach the expected behavior and the target performances,discover possible bottlenecks and ways to correct for them,and explore alternative algorithms and new architectures.To achieve this the complete TRG/DAQ system has been formally specified.and the verification of the expected behavior has been performed through the execution of the specification,Two tools were used for this.Foresight,and Ptolemy.     

羊八井ARGO实验触发效率的地磁场效应

广延大气簇射(EAS)中次级带电粒子在地磁场中偏转,影响次级粒子的横向分布.本文简要分析了羊八井宇宙线观测站不同天顶角的地磁场因子随方位角的变化,表明地磁场对从北方来的宇宙线次级粒子横向分布的影响比对南方来的大.利用蒙特卡罗方法模拟了有无地磁场情况下两个大容量的EAS样本,采用ARGOG探测器模拟程序模拟羊八井ARGO阵列的触发效率.模拟结果表明在忽略地磁场影响时阵列的触发效率确是各向同性的,有地磁场时触发效率南高于北,且原初粒子的天顶角越大,这种南北不对称性越明显.     

神龙一号电子束束参数测量系统猝发式的精确触发方式研究

为了准确了解电子束随时间变化的性能, 在神龙一号直线感应加速器上进行电子束束参数测量时要求测量系统精确地同步于电子束的产生和输运. 其功率系统开关放电波形后沿幅度高达250kV, 下降时间约20ns, 并且从该下降沿到电子束打靶的时间有145ns, 抖动1—2ns, 非常稳定; 如果以陡峭的后沿作为测量时间基准, 则可以获得与其抖动相同量级的同步精度. 因此通过对其波形的下降沿进行微分来获取测量系统的触发信号, 选择合适的微分参数可以得到对应于下降沿 约ns级精度的测量时间基准, 通过采用光纤驱动电路完全消除了高压开关对低压测量系统的干扰, 保证测量系统正常工作. 该方法消除了传统触发方式因延时长、精度低、抖动大等对确定测量时间基准的不利影响, 满足了使用高速测量设备准确获取电子束不同时刻的束参数波形的精确触发要求.     

羊八井ARGO实验数据获取系统

羊八井ARGO实验采用全覆盖式RPC阵列探测小空气簇射事例,其数据获取系统基于多级高速缓存和高速事例驱动机制,硬件实现数据获取和事例组建,从而避免了软件对数据采集速度的影响和CPU的开销,满足了21.7kHz的触发率和6.4M字节/s的数据率的实验要求.     

Simulation of BES Trigger

A simulation program of BES trigger is described and a comparison of its results with experimental data is presented. With this program, the efficiencies of BES trigger system for different kinds of events generated by Monte-Carlo simulation are given for the first time and they are consistent with those measured by the experimental method. It proves that this trigger simulation code is suitable for studying the performance of BES trigger system and is a Complement of BES Monte-Carlo simulation code library.     

北京谱仪触发判选系统的模拟

介绍了北京谱仪(BES)触发判选系统的模拟程序,并用实验数据对其正确性作了验证.运用该程序,首次用BES的蒙特卡罗(Monte Carlo)数据从系统角度直接给出了触发判选效率,所得结果与实验方法测定的触发效率相一致,说明触发判选系统符合BES物理取数的要求.该模拟软件可以用来完备BES的Monte Carlo程序库,并可为今后触发系统的研究提供参考数据.