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.
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).
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 Gbps 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 discusses hadron energy reconstruction for the ATLAS barrel prototype combined calorimeter (consisting of a lead-liquid argon electromagnetic part and an iron-scintillator hadronic part) ...in the framework of the non-parametrical method. The non-parametrical method utilizes only the known $e/h$ ratios and the electron calibration constants and does not require the determination of any parameters by a minimization technique. Thus, this technique lends itself to an easy use in a first level trigger. The reconstructed mean values of the hadron energies are within $\pm 1%$ of the true values and the fractional energy resolution is $(58\pm3)% /\sqrt{E}+(2.5\pm0.3)%\oplus (1.7\pm0.2)/E$. The value of the $e/h$ ratio obtained for the electromagnetic compartment of the combined calorimeter is $1.74\pm0.04$ and agrees with the prediction that $e/h > 1.7$ for this electromagnetic calorimeter. Results of a study of the longitudinal hadronic shower development are also presented. The data have been taken in the H8 beam line of the CERN SPS using pions of energies from 10 to 300 GeV.
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