Status of the BELLE II Pixel Detector

The Belle II experiment at the super KEK B-factory (SuperKEKB) in Tsukuba, Japan, has been collecting $e^+e^−$ collision data since March 2019. Operating at a record-breaking luminosity of up to $4.7×10^{34} cm^{−2}s^{−1}$, data corresponding to $424 fb^{−1}$ has since been recorded. The Belle II VerteX Detector (VXD) is central to the Belle II detector and its physics program and plays a crucial role in reconstructing precise primary and decay vertices. It consists of the outer 4-layer Silicon Vertex Detector (SVD) using double sided silicon strips and the inner two-layer PiXel Detector (PXD) based on the Depleted P-channel Field Effect Transistor (DePFET) technology. The PXD DePFET structure combines signal generation and amplification within pixels with a minimum pitch of $(50×55) μm^2$. A high gain and a high signal-to-noise ratio allow thinning the pixels to $75 μm$ while retaining a high pixel hit efficiency of about $99$. As a consequence, also the material budget of the full detector is kept low at $≈0.21$$\frac{X}{X_0}$ per layer in the acceptance region. This also includes contributions from the control, Analog-to-Digital Converter (ADC), and data processing Application Specific Integrated Circuits (ASICs) as well as from cooling and support structures. This article will present the experience gained from four years of operating PXD; the first full scale detector employing the DePFET technology in High Energy Physics. Overall, the PXD has met the expectations. Operating in the intense SuperKEKB environment poses many challenges that will also be discussed. The current PXD system remains incomplete with only 20 out of 40 modules having been installed. A full replacement has been constructed and is currently in its final testing stage before it will be installed into Belle II during the ongoing long shutdown that will last throughout 2023

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

Central tracking detector concepts for the CLIC e+e−e^{+} e^{-} collider

Two possible concepts for a large central tracker for a future CLIC detector are discussed, including a large TPC and a full Silicon Tracker. The expected performance of a proposed Silicon Tracker is evaluated at square root s=3 TeV using a GEANT simulation. (9 refs)

Ecologia alimentar da coruja Tyto furcata: um estudo no extremo sul do Brasil

Este trabalho objetivou avaliar a variação temporal na ocorrência, bem como na abundância em que roedor, principal item alimentar, é consumido pela coruja T. furcata e relacionar tal consumo com a ocorrência e abundância de outras presas encontradas em sua dieta ao longo do ano, em uma paisagem com predominância de campos, banhados e plantações de arroz

Mapping the material distribution of a complex structure in an electron beam

The simulation and analysis of High Energy Physics experiments require a realisticsimulation of the detector material and its distribution. The challenge is to describe all activeand passive parts of large scale detectors like ATLAS in terms of their size, position and materialcomposition. The common method for estimating the radiation length by weighing individualcomponents, adding up their contributions and averaging the resulting material distribution overextended structures provides a good general estimate, but can deviate significantly from the materialactually present.A method has been developed to assess its material distribution with high spatial resolutionusing the reconstructed scattering angles and hit positions of high energy electron tracks traversingan object under investigation. The study presented here shows measurements for an extendedstructure with a highly inhomogeneous material distribution. The structure under investigation isan End-of-Substructure-card prototype designed for the ATLAS Inner Tracker strip tracker — aPCB populated with components of a large range of material budgets and sizes.The measurements presented here summarise requirements for data samples and reconstructedelectron tracks for reliable image reconstruction of large scale, inhomogeneous samples, choicesof pixel sizes compared to the size of features under investigation as well as a bremsstrahlungcorrection for high material densities and thicknesses

Effects of gamma irradiation on DEPFET pixel sensors for the Belle II experiment

For the Belle II experiment at KEK (Tsukuba, Japan) the KEKB accelerator was upgraded to deliver a 40 times larger instantaneous luminosity than before, which requires an increased radiation hardness of the detector components. As the innermost part of the Belle II detector, the pixel detector (PXD), based on DEPFET (DEpleted P-channel Field Effect Transistor) technology, is most exposed to radiation from the accelerator. An irradiation campaign was performed to verify that the PXD can cope with the expected amount of radiation. We present the results of this measurement campaign in which an X-ray machine was used to irradiate a single PXD half-ladder to a total dose of 266 kGy. The half-ladder is from the same batch as the half-ladders used for Belle II. According to simulations, the total accumulated dose corresponds to 7–10 years of Belle II operation. While individual components have been irradiated before, this campaign is the first full system irradiation. We discuss the effects on the DEPFET sensors, as well as the performance of the front-end electronics. In addition, we present efficiency studies of the half-ladder from beam tests performed before and after the irradiation