32 research outputs found

    Results from a combined test of an electromagnetic liquid argon calorimeter with a hadronic scintillating-tile calorimeter

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    The first combined test of an electromagnetic liquid argon accordion calorimeter and a hadronic scintillating-tile calorimeter was carried out at the CERN SPS. These devices are prototypes of the barrel calorimeter of the future ATLAS experiment at the LHC. The energy resolution of pions in the energy range from 20 to 300~GeV at an incident angle θ\theta of about 11^\circ is well-described by the expression \sigma/E = ((46.5 \pm 6.0)\%/\sqrt{E} +(1.2 \pm 0.3)\%) \oplus (3.2 \pm 0.4)~\mbox{GeV}/E. Shower profiles, shower leakage, and the angular resolution of hadronic showers were also studied

    Response of the ATLAS tile calorimeter prototype to muons

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    A study of high energy muons traversing the ATLAS hadron Tile calorimeter in the barrel region in the energy range between 10 and 300~GeV is presented. Both test beam experimental data and Monte Carlo simulations are given and show good agreement. The Tile calorimeter capability of detecting isolated muons over the above energy range is demonstrated. A signal to background ratio of about 10 is expected for the nominal LHC luminosity (1034cm2sec110^{34} cm^{-2} sec^{-1}). The photoelectron statistics effect in the muon shape response is shown. The e/mip ratio is found to be 0.81±0.03 0.81 \pm 0.03; the e/μ\mu ratio is in the range 0.91 - 0.97. The energy loss of a muon in the calorimeter, dominated by the energy lost in the absorber, can be correlated to the energy loss in the active material. This correlation allows one to correct on an event by event basis the muon energy loss in the calorimeter and therefore reduce the low energy tails in the muon momentum distribution

    Evaluation of Fermi Read-out of the ATLAS Tilecal Prototype

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    Prototypes of the \fermi{} system have been used to read out a prototype of the \atlas{} hadron calorimeter in a beam test at the CERN SPS. The \fermi{} read-out system, using a compressor and a 40 MHz sampling ADC, is compared to a standard charge integrating read-out by measuring the energy resolution of the calorimeter separately with the two systems on the same events. Signal processing techniques have been designed to optimize the treatment of \fermi{} data. The resulting energy resolution is better than the one obtained with the standard read-out

    A measurement of the energy loss spectrum of 150 GeV muons in iron

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    The energy loss spectrum of 150 GeV muons has been measured with a prototype of the ATLAS hadron calorimeter in the H8 beam of the CERN SPS.\\ The differential probability dP/dvdP/dv per radiation length of a fractional energy loss v=ΔEμ/Eμv = \Delta E_{\mu} / E_{\mu} has been measured in the range v=0.01÷0.95v = 0.01 \div 0.95 ; it is then compared with the theoretical predictions for energy losses due to bremsstrahlung and production of electron-positron pairs or of energetic knock-on electrons.\\ The integrated probability 0.010.95(dP/dv)dv\int_{0.01}^{0.95} (dP/dv) dv is (1.610±0.015stat.±0.105syst.)103(1.610\pm0.015_{stat.}\pm0.105_{syst.})\cdot10^{-3} in agreement with the theoretical predictions of 1.5561031.556\cdot10^{-3} and 1.6191031.619\cdot10^{-3}. %7.8.96 - start Agreement with theory is also found in two intervals of vv where production of electron-positron pairs and knock-on electrons dominates. In the region of bremsstrahlung dominance (v=0.12÷0.95v = 0.12\div0.95) the measured integrated probability (1.160±0.040stat±0.075syst)104(1.160\pm0.040_{stat}\pm0.075_{syst})\cdot 10^{-4} is in agreement with the theoretical value of 1.1851041.185 \cdot 10^{-4} , obtained using Petrukhin and Shestakov's \cite{PS} description of the bremsstrahlung process. The same result is about 3.6 standard deviations (defined as the quadratic sum of statistical and systematic errors) lower than the theoretical prediction of 1.472104 1.472\cdot 10^{-4}, obtained using Tsai's \cite{TS} description of bremsstrahlung

    Cooperação entre redes neurais artificiais e técnicas 'clássicas' para previsão de demanda de uma série de vendas de cerveja na Austrália

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    O principal objetivo deste trabalho é avaliar a complementação do uso de técnicas de previsão de vendas com Redes Neurais Artificiais. Como aplicação, foi analisada a demanda industrial no setor de cerveja da Austrália. A maioria dos modelos de previsão atuam de forma isolada, ou seja, tratando problemas por enfoques que se excluem. A sugestão deste trabalho é utilizar estes métodos de forma cooperativa, buscando alcançar melhores resultados que aqueles obtidos individualmente. O trabalho inicia-se com considerações sobre previsões de séries temporais, caracterização breve sobre redes neurais e outros métodos de previsão. A seguir, o estudo de caso: uma série histórica de vendas de cerveja na Austrália. Encerra-se com uma conclusão e recomendações, e lista de referências bibliográficas.<br>The main goal of this article is to evaluate the complementation between forecasting techniques, in particular Neural Networks. The environment of the application is a foreign industrial sector, sales of beer in Australia. Most of the forecasting models act in a separate way, that is, treating problems through different views that exclude one another. The suggestion of this work is to use the methods in a cooperative way, looking forward to achieve better results. The article begins with some considerations on Time Series Studies, followed by a brief characterization of Neural Networks and the other methods used on this work. Continuing, the case is presented and discussed and finishing, conclusions and a list of references
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