72 research outputs found

    Influence of the Nanostructures on the Surface and Bulk Physical Properties of Materials

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    Fullerenes, nanotubes, quantum dots are considered as effective sensitizers to modify both the optical, nonlinear optical features, dynamic and polarization characteristics, as well as mechanical and spectral properties of the organic and inorganic materials. The correlation between photorefractivity and photoconductivity was supported and the relation between charge carrier mobility of pure conjugated structures and nanoobjects-doped ones has been revealed. An increase of transmission of nanostructured polarization films was observed. An extension of the nanocomposites applications area is considered

    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

    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

    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
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