基于VME总线的触发硬件测试系统设计

介绍了VME手动机箱控制器与VME通道显示板的设计.在设计中充分利用FPGA的特点,因而该系统具有简单,可靠性高,以及灵活可变的特点.     

Implementation and performance of the third level muon trigger of the ATLAS experiment at LHC

The trigger system of the ATLAS experiment at the LHC aims at a high selectivity in order to keep the full physics potential while reducing the 40 MHz initial event rate imposed by the LHC bunch crossing down to /spl sim/100 Hz, as required by the data acquisition system. Algorithms working in the final stage of the trigger environment (Event Filter) are implemented to run both in a "wrapped" mode (reconstructing tracks in the entire Muon Spectrometer) and in a "seeded" mode (according to a dedicated strategy that performs pattern recognition only in regions of the detector where trigger hypotheses have been produced at earlier stages). The working principles of the offline muon reconstruction and identification algorithms (MOORE and MuId) implemented and used in the framework of the Event Filter are discussed in this paper. The reconstruction performance of these algorithms is presented for both modes in terms of efficiency, momentum resolution, rejection power and execution times on several samples of simulated single muon events, also taking into account the high background environment expected for ATLAS.     

一种可用于在线触发的移位寻迹方法

介绍了一种简单高速移位寻迹方法,这种方法易用可编程逻辑器件实现,可以快速高效地找到事例径迹,同时该方法容易分解为流水线结构,响应速度更快,可以用于在线触发系统。     

高温剪断式触发吸收球非能动停堆装置可行性分析

非能动停堆系统是事故工况下核能系统的重要安全保障。为保证和增强钍基熔盐堆核能系统的安全性,通过对比分析现有的非能动停堆装置,本文提出了钍基熔盐堆高温剪断式触发吸收球非能动停堆装置。利用Inconel 625合金在650-700°C力学特性发生陡降的特点,对高温剪断式触发结构——薄壁挡板进行设计,并通过Abaqus软件对其二维结构在事故工况下不同温度时的响应状态进行稳态、瞬态断裂模拟。模拟结果表明,当设定温度超过650°C且持续升高时,薄壁挡板会在4-10 s内发生断裂;在非事故工况下,若温度异常升高到670°C后随即降低时,薄壁挡板不会发生断裂。因此,在紧急事故工况时,设计的高温剪断式触发结构能够可靠剪断,确保第二停堆系统非能动触发,进一步提高钍基熔盐堆的安全性。     

On the mean lifetime of the delayed muon fission

It was found that the mean lifetime of the delayed muon fission of some even-Z target nuclei is correlated to their 2Z − N values. This correlation was used to predict the lifetime of the delayed muon fission in some target isotopes of Th, U and Pu.     

Effects of the two-color laser on relativistic muon motion

Considering the mixture after muon-catalyzed fusion(μCF) reaction as overdense plasma,we analyze muon motion in the plasma induced by a linearly polarized two-colour laser,particularly,the effect of laser parameters on the muon momentum and trajectory.The results show that muon drift along the propagation of laser and oscillation perpendicular to the propagation remain after the end of the laser pulse.Under appropriate parameters,muon can go from the skin layer into field-free matter in a time period of much less than the pulse duration.The electric-field strength ratio or frequency ratio of the fundamental to the harmonic has more influence on muon oscillation.The laser affects little on other particles in the plasma.Hence,in theory,this work can avoid muon sticking to α effectively and reduce muon-loss probability in μCF.     

ARGO-YBJ实验硬件系统

中意合作ARGO-YBJ实验采用全覆盖地毯式RPC探测器阵列来探测广延空气簇射事例.讨论了该实验硬件系统结构及工作原理,分析了实验信号采集、处理、传输、缓存和数据输出过程.最后对该实验在"scaler"模式下记录的数据进行了处理分析,结果显示中心区探测器群(Clusters)运行稳定.     

Implementation of muon interaction models in PHITS

We have constructed models for muon interactions (i.e., bremsstrahlung, electron–positron pair production, muon photonuclear interaction, and negative muon capture reaction) and implemented these models in the particle and heavy ion transport code system (PHITS). The PHITS2.86 agrees well with experimental data for the vertical intensities of cosmic-ray muons in water and standard rock. The calculated results for neutron production by muon photonuclear interaction and negative muon capture reaction are in good agreement with measured data, except in the case of lead target. PHITS2.86 can also reproduce the cross-section of radionuclide production by muons passing through a concrete wall very well. These results indicate the applicability of PHITS2.86 to the shielding design of muon facilities in which estimations of attenuation length and induced radioactivity are important.     

Reconstruction of a muon bundle in the JUNO central detector

The Jiangmen Underground Neutrino Observatory(JUNO) is a multi-purpose neutrino experiment. One of the main goals is to determine the neutrino mass ordering by precisely measuring the energy spectrum of reactor antineutrinos. For the detection of reactor antineutrinos, cosmogenic backgrounds, such as9Li/8He and fast neutrons induced by cosmic muons, should be rejected carefully by applying muon veto cuts, which require good muon track reconstruction. With a 20-kton liquid scintillator detector, ...     

Reconstruction of a muon bundle in the JUNO central detector

The Jiangmen Underground Neutrino Observatory(JUNO) is a multi-purpose neutrino experiment. One of the main goals is to determine the neutrino mass ordering by precisely measuring the energy spectrum of reactor antineutrinos. For the detection of reactor antineutrinos, cosmogenic backgrounds, such as9Li/8He and fast neutrons induced by cosmic muons, should be rejected carefully by applying muon veto cuts, which require good muon track reconstruction. With a 20-kton liquid scintillator detector, ...     

Conceptual design of the CMS trigger supervisor

The Trigger Supervisor is an online software system designed for the CMS experiment at CERN. Its purpose is to provide a framework to set up, test, operate and monitor the trigger components on one hand and to manage their interplay and the information exchange with the run control part of the data acquisition system on the other. The Trigger Supervisor is conceived to provide a simple and homogeneous client interface to the online software infrastructure of the trigger subsystems. The functional and nonfunctional requirements, the design, the operational details, and the components needed in order to facilitate a smooth integration of the trigger software in the context of CMS are described.     

基于FPGA的μ子鉴别器读出系统前端电路

介绍了北京谱仪第三代工程(BESⅢ)中的μ子鉴别器读出系统的前端电路设计,包括系统的结构、各部件的基本功能和工作原理、触发选通逻辑的设计和系统防干扰等关键问题的设计思路和实现方法,以及采用FPGA的实现过程.经过系统检测,前端电路及其组成的数据链全部实现了预期的设计目标.     

A possible scheme for the surface muon beamline at CSNS

An experimental muon source is planned for the China Spallation Neutron Source. A simplified beamline with a limited number of magnets is achieved using a FODO lattice for implementation in a future preliminary stage. The yield of the muon delivered to the experimental sample is slightly larger than 10~5 μ~+/s within the FWHM beam spot(~?30 mm) from a thick muon target. In addition, the beam polarization is 92% and the contamination that is mainly formed by positrons is approximately a fraction of 1%.     

将快法探头应用于物理诊断系统触发的技术研究

在零功率堆上进行中子衰变常数测量实验中,建立外中子源DT中子测量系统可以为物理诊断系统提供触发信号和时间关联信号。简述了触发和时间关联系统的基本组成及相关技术。     

Cable attenuation study of Tibet water Cherenkov muon detector array-A

This work aims at online calibration of signal attenuation of the long cable used in Tibet water Cherenkov muon detector array-A (Tibet MD-A) under the Tibet air shower array.Based on a waterproof connection of the signal cable to PMT (R3600_06) and characters of the high voltage divider,terminal reflection method is used for measuring the signal attenuation with a practical way to eliminate contribution of the pulse baseline.Comparison measurement data-taking method (with charge-to-digital conversion) was ...