1,736 research outputs found

    Characterization of Czochralski silicon detectors

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    This thesis describes the characterization of irradiated and non-irradiated segmented detectors made of high-resistivity (>1¬†kő©cm) magnetic Czochralski (MCZ) silicon. It is shown that the radiation hardness (RH) of the protons of these detectors is higher than that of devices made of traditional materials such as Float Zone (FZ) silicon or Diffusion Oxygenated Float Zone (DOFZ) silicon due to the presence of intrinsic oxygen (>¬†5¬†√ó¬†1017¬†cm‚ąí3). The MCZ devices therefore present an interesting alternative for future high-energy physics experiments. In the large hadron collider (LHC), the RH of the detectors is a critical issue due to the high luminosity (1034¬†cm‚ąí2s‚ąí1) corresponding to the expected total fluencies of fast hadrons above 1015¬†cm‚ąí2. This RH improvement is important since radiation damage in the detector bulk material reduces the detector performance and because some of the devices produced from standard detector-grade silicon, e.g. FZ silicon with negligible oxygen concentration, might not survive the planned operational period of the LHC experiments. In this work, segmented detectors and test structures were processed, measured, irradiated with different particles (protons of different energies, neutrons and high-energy electrons) and tested with a 60Co gamma source and with high-energy muon and pion beams. The electrical characterizations show that, for proton irradiation, the MCZ silicon is significantly radiation harder than traditionally used detector materials. In gamma irradiation, MCZ silicon detectors behave similarly to the DOFZ silicon detectors. For neutron radiation, there is only a small difference between MCZ silicon and the reference devices made of standard FZ silicon. The beam test results with the full-size detectors show that the properties of the high-resistivity MCZ silicon are suitable for particle detection both before and after heavy proton irradiation.reviewe

    Differential cross section measurements for the production of a W boson in association with jets in proton‚Äďproton collisions at ‚ąös = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript ‚ąí1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an