37 research outputs found
Charged particle detection performances of CMOS pixel sensors produced in a 0.18 um process with a high resistivity epitaxial layer
The apparatus of the ALICE experiment at CERN will be upgraded in 2017/18
during the second long shutdown of the LHC (LS2). A major motivation for this
upgrade is to extend the physics reach for charmed and beauty particles down to
low transverse momenta. This requires a substantial improvement of the spatial
resolution and the data rate capability of the ALICE Inner Tracking System
(ITS). To achieve this goal, the new ITS will be equipped with 50 um thin CMOS
Pixel Sensors (CPS) covering either the 3 innermost layers or all the 7 layers
of the detector. The CPS being developed for the ITS upgrade at IPHC
(Strasbourg) is derived from the MIMOSA 28 sensor realised for the STAR-PXL at
RHIC in a 0.35 um CMOS process. In order to satisfy the ITS upgrade
requirements in terms of readout speed and radiation tolerance, a CMOS process
with a reduced feature size and a high resistivity epitaxial layer should be
exploited. In this respect, the charged particle detection performance and
radiation hardness of the TowerJazz 0.18 um CMOS process were studied with the
help of the first prototype chip MIMOSA 32. The beam tests performed with
negative pions of 120 GeV/c at the CERN-SPS allowed to measure a
signal-to-noise ratio (SNR) for the non-irradiated chip in the range between 22
and 32 depending on the pixel design. The chip irradiated with the combined
dose of 1 MRad and 10^13 n_eq/cm^2 was observed to yield a SNR ranging between
11 and 23 for coolant temperatures varying from 15 C to 30 C. These SNR values
were measured to result in particle detection efficiencies above 99.5% and 98%
before and after irradiation respectively. These satisfactory results allow to
validate the TowerJazz 0.18 um CMOS process for the ALICE ITS upgrade.Comment: (v2) Added hyper-links; (v3) A typo correcte
Development of CMOS Pixel Sensors fully adapted to the ILD Vertex Detector Requirements
CMOS Pixel Sensors are making steady progress towards the specifications of
the ILD vertex detector. Recent developments are summarised, which show that
these devices are close to comply with all major requirements, in particular
the read-out speed needed to cope with the beam related background. This
achievement is grounded on the double- sided ladder concept, which allows
combining signals generated by a single particle in two different sensors, one
devoted to spatial resolution and the other to time stamp, both assembled on
the same mechanical support. The status of the development is overviewed as
well as the plans to finalise it using an advanced CMOS process.Comment: 2011 International Workshop on Future Linear Colliders (LCWS11),
Granada, Spain, 26-30 September 201
Development of CMOS pixel sensors for tracking and vertexing in high energy physics experiments
CMOS pixel sensors (CPS) represent a novel technological approach to building
charged particle detectors. CMOS processes allow to integrate a sensing volume
and readout electronics in a single silicon die allowing to build sensors with
a small pixel pitch () and low material budget () per layer. These characteristics make CPS an attractive option for
vertexing and tracking systems of high energy physics experiments. Moreover,
thanks to the mass production industrial CMOS processes used for the
manufacturing of CPS the fabrication construction cost can be significantly
reduced in comparison to more standard semiconductor technologies. However, the
attainable performance level of the CPS in terms of radiation hardness and
readout speed is mostly determined by the fabrication parameters of the CMOS
processes available on the market rather than by the CPS intrinsic potential.
The permanent evolution of commercial CMOS processes towards smaller feature
sizes and high resistivity epitaxial layers leads to the better radiation
hardness and allows the implementation of accelerated readout circuits. The
TowerJazz CMOS process being one of the most relevant examples
recently became of interest for several future detector projects. The most
imminent of these project is an upgrade of the Inner Tracking System (ITS) of
the ALICE detector at LHC. It will be followed by the Micro-Vertex Detector
(MVD) of the CBM experiment at FAIR. Other experiments like ILD consider CPS as
one of the viable options for flavour tagging and tracking sub-systems
Development of Single- and Double-sided Ladders for the ILD Vertex Detectors
We discuss two projects exploring the integration of thin CMOS pixel sensors
in order to prototype ladders matching the geometry needed for the ILD vertex
detector. The PLUME project has designed and fabricated full-size and fully
functional double- sided layers which currently reach 0.6 % X0 and aim for 0.3
% X0 in mid-2012. Another approach, SERNWIETE, consists in wrapping the sensors
in a polyimide-based micro-cable to obtain a supportless single-sided ladder
with a material budget around 0.15 % X0. First promising samples have been
produced and the full-size prototype is expected in spring 2012.Comment: International Workshop on Future Linear Colliders, LCWS 2011,
Granada, Spain, 2011, 26-30 Septembe
Optimisation of CMOS pixel sensors for high performance vertexing and tracking
CMOS Pixel Sensors tend to become relevant for a growing spectrum of charged
particle detection instruments. This comes mainly from their high granularity
and low material budget. However, several potential applications require a
higher read-out speed and radiation tolerance than those achieved with
available devices based on a 0.35 micrometers feature size technology. This
paper shows preliminary test results of new prototype sensors manufactured in a
0.18 micrometers process based on a high resistivity epitaxial layer of
sizeable thickness. Grounded on these observed performances, we discuss a
development strategy over the coming years to reach a full scale sensor
matching the specifications of the upgraded version of the Inner Tracking
System (ITS) of the ALICE experiment at CERN, for which a sensitive area of up
to about 10 square meters may be equipped with pixel sensors.Comment: Presented at the Vienna Conference on Instrumentation 2013 4 pages, 5
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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