Among other detectors, the T2K neutrino experiment comprises three large time projection chambers segmented into over 124.000 electronics channels. The back-end electronics system is designed to ...distribute a reference clock to the front-end electronics, aggregate event data over seventy-two 2 Gbit/s optical links and format events that are sent via a standard PC to the global data acquisition system of the experiment. The core of this system is a set of 18 Data Concentrator Cards based on an inexpensive commercial Field Programmable Gate Array evaluation kit with specific add-ons. We describe the adaptations that were made to the original platform, and detail the design of the firmware and software running on the embedded PowerPC processor of the FPGA of a Data Concentrator Card. We show how the intrinsic parallelism and a mixed firmware and software implementation of the data reduction and acquisition tasks lead to a flexible system capable of extracting in real time meaningful information from the 2.5 GByte/s of raw event data produced by the front-end electronics at a nominal rate of 20 Hz.
This paper presents the status of a serial protocol developed in the framework of ATLAS (A Toroidal LHC ApparatuS), a high energy physics experiment that will be installed at the Large Hadron ...Collider (LHC) based at CERN. This link will be used to control the front-end electronics of the liquid argon calorimeters, located in an irradiated environment. After a technical description of the communication system architecture, we detail the features and performances of the designed components. This protocol could be applied in other contexts (nuclear physics, industry) where a fast, reliable and radhard serial communication is needed.
A search for the Standard Model Higgs boson has been performed in the H->WW->lnujj channel using 4.7 fb^-1 of pp collision data recorded at a centre-of-mass energy of sqrt(s) = 7 TeV with the ATLAS ...detector at the Large Hadron Collider. Higgs boson candidates produced in association with zero, one or two jets are included in the analysis to maximize the acceptance for both gluon fusion and weak boson fusion Higgs boson production processes. No significant excess of events is observed over the expected background and limits on the Higgs boson production cross section are derived for a Higgs boson mass in the range 300 GeV < mH < 600 GeV. The best sensitivity is reached for mH = 400 GeV, where the observed (expected) 95% confidence level upper bound on the cross section for H->WW produced in association with zero or one jet is 2.2 pb (1.9 pb), corresponding to 1.9 (1.6) times the Standard Model prediction. In the Higgs boson plus two jets channel, which is more sensitive to the weak boson fusion process, the observed (expected) 95% confidence level upper bound on the cross section for H->WW production with mH = 400 GeV is 0.7 pb (0.6 pb), corresponding to 7.9 (6.5) times the Standard Model prediction.
A search for a heavy Standard Model Higgs boson decaying via H->ZZ->llnunu, where l=e,mu, is presented. It is based on proton-proton collision data at sqrt(s)=7 TeV, collected by the ATLAS experiment ...at the LHC in the first half of 2011 and corresponding to an integrated luminosity of 1.04 fb^-1. The data are compared to the expected Standard Model backgrounds. The data and the combined background expectations are found to be in agreement and upper limits are placed on the Higgs boson production cross section over the entire mass window considered; in particular the production of a Standard Model Higgs boson is excluded in the region 340 < m_H < 450 GeV at the 95% confidence level.
A search for a Higgs boson has been performed in the H->WW->lvjj channel in 1.04/fb of pp collision data sqrt{s} = 7 TeV recorded with the ATLAS detector at the Large Hadron Collider. No significant ...excess of events is observed over the expected background and limits on the Higgs boson production cross section are derived for a Higgs boson mass in the range 240 GeV < mH < 600 GeV. The best sensitivity is reached for mH = 400 GeV, where the 95% confidence level upper bound on the cross section for H->WW production is 3.1 pb, or 2.7 times the Standard Model prediction.
The OMEGAPIX2 chip embeds a matrix of channels implemented in two vertically integrated (3D) circuits and designed to read out a matrix of 96×24 plannar pixels. The form factor of each pixel is ...35×200 μm. The first 3D devices's layer includes the analogue part of the channel processing, it will be bounded to the sensor by connecting the channel inputs and the sensors pixels by the Through Silicon Vias (TSV); the other layer performs the digital memorization of each events and manages the sorting of good events after the Level 1 (L1) trigger acquisition. In this paper, the 3D technology is briefly described, some design considerations are discussed and some typical simulations are shown. The circuit has been submitted in October 2011 and is waited to be received in December 2012.
A search for new interactions and resonances produced in LHC proton-proton (pp) collisions at a centre-of-mass energy sqrt(s)= 7 TeV has been performed with the ATLAS detector. Using a data set with ...an integrated luminosity of 36 pb-1 dijet mass and angular distributions have been measured up to dijet masses of \sim 3.5 TeV and found to be in good agreement with Standard Model predictions. This analysis sets limits at 95% C.L. on various models for new physics: an excited quark is excluded with mass between 0.60 and 2.64 TeV, an axigluon hypothesis is excluded for axigluon masses between 0.60 and 2.10 TeV and Randall-Meade quantum black holes are excluded in models with six extra space-time dimensions for quantum gravity scales between 0.75 and 3.67 TeV. Production cross section limits as a function of dijet mass are set using a simplified Gaussian signal model to facilitate comparisons with other hypotheses. Analysis of the dijet angular distribution using a novel technique 18 simultaneously employing the dijet mass excludes quark contact interactions with a compositeness scale {\Lambda} below 9.5 TeV.
Performance of the ATLAS electromagnetic calorimeter end-cap module 0 Ballansat, J; Bazan, A; Beaugiraud, B ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2003, Letnik:
500, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The construction and beam test results of the ATLAS electromagnetic end-cap calorimeter pre-production module 0 are presented. The stochastic term of the energy resolution is between 10% and
12.5%
...GeV
1/2
over the full pseudorapidity range. Position and angular resolutions are found to be in agreement with simulation. A global constant term of 0.6% is obtained in the pseudorapidity range 2.5<
η<3.2 (inner wheel).
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