216 research outputs found
RD53 Collaboration and CHIPIX65 Project for the development of an innovative Pixel Front End Chip for HL-LHC
Full text linkMeasurement of the WW cross section in √s = 7 TeV pp collisions with the ATLAS detector and limits on anomalous gauge couplings
Full text linkThis Letter reports a measurement of the WW production cross section in
√
s = 7 TeV pp collisions
using data corresponding to an integrated luminosity of 1.02 fb−1 collected with the ATLAS detector.
Using leptonic decays of oppositely charged W bosons, the total measured cross section is σ(pp →
WW) = 54.4 ± 4.0 (stat.) ± 3.9 (syst.) ± 2.0 (lumi.) pb, consistent with the Standard Model prediction
of σ(pp→WW) = 44.4±2.8 pb. Limits on anomalous electroweak triple-gauge couplings are extracted
from a fit to the transverse-momentum distribution of the leading charged lepton in the even
Vertically integrated CMOS active pixel sensors for tracking applications in HEP experiments
No full textn this work we propose an innovative approach to particle tracking based on CMOS Active Pixel Sensors layers, monolithically integrated in an all-in-one chip featuring multiple, stacked, fully functional detector layers capable to provide momentum measurements (particle impact point and direction) within a single detector. This will results in a very low material detector, thus dramatically reducing multiple scattering issues. A first chip prototype has been fabricated within a multi-project run using a 130nm CMOS 3D Chartered/Tezzaron technology, featuring two layers bonded face-to-face. Tests have been carried out on full 3D structures, providing the functionalities of both tiers and their inter-communications. Actually, laser scans have been carried out using highly focussed spot size, obtaining coincidence responses of the two layers. X-rays sources have been used as well for sensor calibration purposes. Beam tests with 3MeV protons have been carried out at the INFN LABEC laboratories in Florence (Italy) to assess the suitability of the proposed approach for Minimum Ionizing Particle detection
Search for heavy vector-like quarks coupling to light quarks in proton–proton collisions at √s = 7 TeV with the ATLAS detector
Full text link<p>This Letter presents a search for singly produced vector-like quarks, Q, coupling to light quarks, <i>q</i>. The search is sensitive to both charged current (CC) and neutral current (NC) processes, <i>pp→Qq→Wqq′</i> and <i>pp→Qq→Zqq′</i> with a leptonic decay of the vector gauge boson. In 1.04 fb<sup>−1</sup> of data taken in 2011 by the ATLAS experiment at a center-of-mass energy √s = 7 TeV, no evidence of such heavy vector-like quarks is observed above the expected Standard Model background. Limits on the heavy vector-like quark production cross section times branching ratio as a function of mass mQ are obtained. For a coupling <sub>κq</sub>Q=v/mQ, where <i>v</i> is the Higgs vacuum expectation value, 95% C.L. lower limits on the mass of a vector-like quark are set at 900 GeV and 760 GeV from CC and NC processes, respectively.</p>
Test of a MAPS realized in standard non-epitaxial CMOS technology
No full textAn active pixel sensor has been developed using standard CMOS technology, UMC 0 :18 mm with no epitaxial layer, with pixel size
4:4 4 :4 m m, in the framework of the INFN RAPS project. In this work we will report on the results obtained using several types of
ionizing radiation sources (laser, X-ray tubes, b and g) to test extensively the device. Some of the main results obtained are: a signal/noise
value for minimum ionizing particles of about 20, a very good linearity of the response, a good spatial confinement of the signal (cluster size of the order of few pixels)
RAPS: an Innovative Active Pixel for Particle Detection Integrated in CMOS Technology
No full textAbstract: In this paper we discuss some design, implementation and test issues, with respect to the development of the RAPS01 chip in the framework of the Radiation Active Pixel Sensors (RAPS) INFN project. The project aimed at verifying feasibility of smart, high-resolution pixel arrays with a fully standard, submicron CMOS technology for particle detection purposes. Layout optimization of the pixel, including sensitive element and local read and amplification circuits has been carried out. Different basic pixel schemes and read-out options have been proposed and devised. Chip fabrication has been completed and test phase is now under way: to this purpose a suitable test environment has been devised and test strategies have been planned. (C) 2003 Elsevier B.V. All rights reserved
Search for stable hadronising squarks and gluinos with the ATLAS experiment at the LHC
Full text linkHitherto unobserved long-lived massive particles with electric and/or colour charge are predicted by a range of theories which extend the Standard Model. In this Letter a search is performed at the ATLAS experiment for slow-moving charged particles produced in proton–proton collisions at 7 TeV centre-of-mass energy at the LHC, using a data-set corresponding to an integrated luminosity of 34 pb−1. No deviations from Standard Model expectations are found. This result is interpreted in a framework of supersymmetry models in which coloured sparticles can hadronise into long-lived bound hadronic states, termed R-hadrons, and 95% CL limits are set on the production cross-sections of squarks and gluinos. The influence of R-hadron interactions in matter was studied using a number of different models, and lower mass limits for stable sbottoms and stops are found to be 294 and 309 GeV respectively. The lower mass limit for a stable gluino lies in the range from 562 to 586 GeV depending on the model assumed. Each of these constraints is the most stringent to date
Test of a MAPS realized in standard non-epitaxial CMOS 0.18um technology
No full textAn active pixel sensor has been developed using standard CMOS technology, UMC 0:18 mm with no epitaxial layer, with pixel size 4:4 4:4 mm, in the framework of the INFN RAPS project. In this work we will report on the results obtained using several types of ionizing radiation sources (laser, X-ray tubes, b and g) to test extensively the device. Some of the main results obtained are: a signal/noise value for minimum ionizing particles of about 20, a very good linearity of the response, a good spatial confinement of the signal (cluster size of the order of few pixels)
Design, Fabrication, and Test of CMOS Active-Pixel Radiation Sensors
No full textIn this paper, we discuss some issues related to the design,
implementation, and test of a CMOS active pixel sensor chip (RAPS01),
developed in the framework of the radiation active pixel sensors
(RAPS) INFN project. Two different basic pixel schemes have been
proposed. The first one is based on a standard active pixel sensor
(APS) architecture, while a second architecture, named weak inversion
pixel sensor (WIPS) exploits a different circuitry which allows for
"sparse" access mode and thus for speeding-up the readout phase. Chip
fabrication has been completed and a preliminary test phase has been
performed. A suitable test environment has been devised and test
strategies have been planned. Preliminary test results, featuring a
static and dynamic characterization of the basic sensitive elements
are outlined. Future works are also outlined, aimed at the
optimization of a second version of the chip, more effectively
integrating smart circuitry
Silicon Strip Detectors for LHC: Comprehensive Process and Device Analysis
No full textIn this paper, the application of technology CAD methodologies to design and optimization of Silicon Microstrip Detectors is described. More specifically, extensive use of both process and device simulation has been made, in order to predict the performance of DC and AC-coupled detectors being fabricated at CSEM SA Neuchatel, Switzerland, in the framework of a CERN R&D collaboration. Such devices, intended to be part of the CMS-project Si-Tracker, have also been extensively tested at the INFN laboratories in Perugia, Italy. Satisfactory agreement between measured and simulated data has been found. This validates the proposed approch, which allows fo fast and inexpensive characterization of "virtual" devices
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