A Lightweight Field Cage for a Large TPC Prototype for the ILC

We have developed and constructed the field cage of a prototype Time Projection Chamber for research and development studies for a detector at the International Linear Collider. This prototype has an inner diameter of 72 cm and a length of 61 cm. The design of the field cage wall was optimized for a low material budget of 1.21 % of a radiation length and a drift field homogeneity of Delta(E)/(E) less or equal 10^-4. Since November 2008 the prototype has been part of a comprehensive test beam setup at DESY and used as a test chamber for the development of Micro Pattern Gas Detector based readout devices.Comment: 16 pages, 13 figures, 3 table

Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks

无线传感器网络，作为全球未来十大技术之一，集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术，可实时感知、采集、处理、传输网络分布区域内的各种信息数据，在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议，并针对大规模的无线传感器网络设计了一种树状路由协议，它根据节点地址信息来形成路由，从而简化了复杂繁冗的路由表查找和维护，节省了不必要的开销，提高了路由效率，实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR（AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位：工学硕士院系专业：信息科学与技术学院通信工程系_通信与信息系统学号：2332007115216

Analysis of GEM Properties and Development of a GEM Support Structure for the ILD Time Projection Chamber

In the concept of the International Large Detector (ILD), developed for the International Linear Collider (ILC) a Time Projection Chamber (TPC) is envisaged as main tracking detector.Such gaseous detectors have to be equipped with amplification devices in order to enlargethe amount of charge, which is set free by ionization caused by traversing charged particles.Micro Pattern Gas Detectors (MPGDs) will be used in the ILD TPC as amplification stage. Inthis thesis, Gas Electron Multipliers (GEMs) – one specific MPGD species – are analyzed concerning various properties. Effective gains and energy resolutions are compared for GEM foilsproduced by different manufacturers. A good understanding of these observables is obtainedby interpretation of the results with the help of geometrical parameters. Height profile measurements of GEM foils have been performed for the first time and the impact of non perfectflat GEMs is analyzed, especially on dE/dx determination and drift field quality. The resultsemphasize the need of a flat installation of GEMs in TPCs. As a consequence, a new mountingdevice has been developed to ensure flatness and to provide a method to cover large readoutareas, as in the ILD TPC, by introducing the least possible amount of dead material into thedetector. The developed structure has been tested in a TPC protoype, taking cosmic muondata. The influence of the mounting on track reconstruction, single point resolution, trackingefficiency and dE/dx measurements is quantified. The developed mounting is applicable in alarge scale TPC, if some design considerations are taken into account