Nanostructured metal-fullerene field emission cathode

One of the important properties of carbon nanostructures is their cold electron emission ability. Carbon nanotubes and other nanostructures are capable of emitting high currents at relatively low electrical fields. They are already used in functional devices such as field emitters. The conventional method of carbon nanostructured cathodes manufacturing is thin film nanocarbon deposition using CVD process on electrically conducting substrate like metal or doped silicon plates. The alternative way of manufacturing of carbon field emission cathodes is based on a special processing of carbon microfibers or composite materials in metal holders. We used the similar approach to produce composite metal-nanocarbon material which may be easily processed and shaped to produce an effective field emission cathode which can be easily fixed an any environment. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2058

Electric field study with HIBP in OH and ECRH plasmas on the T-10 tokamak

The plasma potential φ and radial electric field Er were studied on T-10 in a wide range of ohmic and ECRH regimes. At densities ne> 10¹⁹ m⁻³, the potential has negative sign over the whole plasma cross section. At lower densities, the outer zone with positive φ and Er is formed. The absolute value of potential at mid-radius grows with density up to ne ≈ 3×10¹⁹ m⁻³ and then saturates. In regimes with ECR heating, |φ| decreases owing to the density pump-out and the electron temperature increase. Measurements of Er are compared with numerical simulations with several codes including nonambipolar fluxes due to the toroidal field ripple. The change of radially averaged ¬Er with density and temperature qualitatively agrees with neoclassical expectations.Потенциал плазмы φ и радиальное электрическое поле Er исследовались на токамаке T-10 в широком диапазоне омических и ЭЦР-режимов. При плотностях ne> 10¹⁹ м⁻³ потенциал имеет положительный знак во всем сечении плазмы. При меньших плотностях во внешней зоне потенциал и Er меняют знак. Абсолютное значение потенциала на середине радиуса растет с плотностью вплоть до ne ≈ 3×10¹⁹ м⁻³, а затем насыщается. В режимах с ЭЦР-нагревом абсолютная величина |φ| уменьшается за счет откачки плотности и роста электронной температуры. Измерения Er сравнивались с численными расчетами по нескольким кодам, учитывающим неамбиполярные потоки за счет гофрировки тороидального поля. Изменение среднего поля ¬Er с плотностью и температурой не противоречит неоклассическим ожиданиям.Потенціал плазми φ та радіальне електричне поле Er було досліджено на токамаці Т-10 у широкому діапазоні омічних та ЕЦР-режимів. При щiльностях ne> 10¹⁹ м⁻³ потенцiал має позитивний знак в усьому перетинi плазми. При менших щiльностях у зовнiшнiй зонi потенціал та Er змiнюють знак. Абсолютне значення потенцiалу на серединi радіуса росте зi щiльністью майже до ne ≈ 3×10¹⁹ м⁻³, а потiм насичується. У режимах з ЕЦР-нагрiвом абсолютна величина |φ|зменшується за рахунок відкачки щiльностi та росту електронноï температури. Вимiрювання Er порiвнювалися з числовими розрахунками за декiлькома кодами, які враховують неамбіполярнi потоки за рахунок гофрировки тороïдального поля. Зміна середнього поля ¬Er з щiльнiстю та температурою не протирiчить неокласичним сподiванням

Study of plasma potential, its fluctuations and turbulence rotation in the T-10 tokamak

Plasma potential, its oscillations and turbulence rotation were studied on T-10 in a wide range of ohmic and ECRH regimes. The potential has negative sign over the whole plasma cross section. Broadband turbulence tends to rotate with E×B drift velocity. Rotation and potential evolve together with plasma confinement. Frequency of potential oscillations in the range of geodesic acoustic modes does not change with radius that disagrees with theoretical predictions.Потенциал плазмы, его колебания и вращение исследовались на токамаке T-10 в широком диапазоне омических и ЭЦР-режимов. Потенциал – отрицательный по всему сечению плазмы. Вращение турбулентности соответствует вращению за счет (E×B)-дрейфа. Вращение и потенциал чувствительны к изменениям удержания. Частота колебаний потенциала в диапазоне геодезических акустических мод не меняется по радиусу, что не соответствует локальной теории ГАМ.Потенціал плазми, його коливання та обертання було досліджено на токамаці Т-10 у широкому діапазоні омічних та ЕЦР-режимів. Потенціал має негативну величину по всьому перетину плазми. Обертання турбуленції відповідає обертанню за рахунок (E×B)-дрейфу. Обертання і потенціал чутливі до зміни утримання. Частота коливань потенціалу у діапазоні геодезичних акустичних мод ні змінюється в залежності від радіусу, що не відповідає локальній теорії ГАМ

Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV

A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.Comment: Submitted to Physics Letters

Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV

The Lambda(b) differential production cross section and the cross section ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7 TeV using data collected by the CMS experiment at the LHC. The measurements are based on Lambda(b) decays reconstructed in the exclusive final state J/Psi Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and Lambda to proton pion, using a data sample corresponding to an integrated luminosity of 1.9 inverse femtobarns. The product of the cross section times the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls faster than that of b mesons. The measured value of the cross section times the branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06 +/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are statistical and systematic, respectively.Comment: Submitted to Physics Letters

Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV

A search is presented for physics beyond the standard model (BSM) in final states with a pair of opposite-sign isolated leptons accompanied by jets and missing transverse energy. The search uses LHC data recorded at a center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to an integrated luminosity of approximately 5 inverse femtobarns. Two complementary search strategies are employed. The first probes models with a specific dilepton production mechanism that leads to a characteristic kinematic edge in the dilepton mass distribution. The second strategy probes models of dilepton production with heavy, colored objects that decay to final states including invisible particles, leading to very large hadronic activity and missing transverse energy. No evidence for an event yield in excess of the standard model expectations is found. Upper limits on the BSM contributions to the signal regions are deduced from the results, which are used to exclude a region of the parameter space of the constrained minimal supersymmetric extension of the standard model. Additional information related to detector efficiencies and response is provided to allow testing specific models of BSM physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO

Measurement of isolated photon production in pp and PbPb collisions at sqrt(sNN) = 2.76 TeV

Isolated photon production is measured in proton-proton and lead-lead collisions at nucleon-nucleon centre-of-mass energies of 2.76 TeV in the pseudorapidity range |eta|<1.44 and transverse energies ET between 20 and 80 GeV with the CMS detector at the LHC. The measured ET spectra are found to be in good agreement with next-to-leading-order perturbative QCD predictions. The ratio of PbPb to pp isolated photon ET-differential yields, scaled by the number of incoherent nucleon-nucleon collisions, is consistent with unity for all PbPb reaction centralities.Comment: Submitted to Physics Letters

Role of turbulence and electric fields in the establishment of improved confinement in tokamak plasmas

An extensive (INTAS) research programme started in 2002 to investigate the correlations between on the one hand the occurrence of transport barriers and improved confinement in the medium-size tokamaks TEXTOR and T-10 and on the smaller tokamaks FT-2, TUMAN-3M and CASTOR, and on the other hand electric fields, modified magnetic shear and electrostatic and magnetic turbulence using advanced diagnostics with high spatial and temporal resolution and of various active means to externally control plasma transport . This has been done in a strongly coordinated way and exploiting the complementarity of TEXTOR and T-10 and the backup potential of the three other tokamaks, which together have all the relevant experimental tools and theoretical expertise

Measurement of the mass difference between top quark and antiquark in pp collisions at root s=8 TeV

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