7,390 research outputs found
CMS Pixel Detector Upgrade
The present Compact Muon Solenoid silicon pixel tracking system has been
designed for a peak luminosity of 1034cm-2s-1 and total dose corresponding to
two years of the Large Hadron Collider (LHC) operation. With the steady
increase of the luminosity expected at the LHC, a new pixel detector with four
barrel layers and three endcap disks is being designed. We will present the key
points of the design: the new geometry, which minimizes the material budget and
increases the tracking points, and the development of a fast digital readout
architecture, which ensures readout efficiency even at high rate. The expected
performances for tracking and vertexing of the new pixel detector are also
addressed.Comment: 5 pages, 7 figures, Proceedings of the DPF-2011 Conference,
Providence, RI, August 8-13, 201
Detection of moisture and moisture related phenomena from Skylab
There are no author-identified significant results in this report
Non-linear electrical conduction and broadband noise in charge-ordered rare earth manganate Nd_0.5Ca_0.5MnO_3
Measurements of the dc transport properties and the low-frequency
conductivity noise in films of charge ordered Nd_0.5Ca_0.5MnO_3 grown on Si
subtrate reveal the existence of a threshold field in the charge ordered regime
beyond which strong non linear conduction sets in along with a large broad band
conductivity noise. Threshold-dependent conduction disappears as T -> T_{CO},
the charge ordering temperature. This observation suggests that the charge
ordered state gets depinned at the onset of the non-linear conduction.Comment: 3 pages of two-column text and 4 eps figure
Kinetic dissipation and anisotropic heating in a turbulent collisionless plasma
The kinetic evolution of the Orszag-Tang vortex is studied using
collisionless hybrid simulations. In the magnetohydrodynamic regime this vortex
leads rapidly to broadband turbulence. Significant differences from MHD arise
at small scales, where the fluid scale energy dissipates into heat almost
exclusively through the magnetic field because the protons are decoupled from
the magnetic field. Although cyclotron resonance is absent, the protons heat
preferentially in the plane perpendicular to the mean field, as in the corona
and solar wind. Effective transport coefficients are calculated.Comment: 4 pages, 4 figures. Submitted to PR
Current-induced phase control in charged-ordered Nd0.5Ca0.5MnO3 and Pr0.6Ca0.4MnO3 crystals
Single crystals of Nd0.5Ca0.5MnO3 and Pr0.6Ca0.4MnO3 show current-induced
insulator-metal transitions at low temperatures. In addition, the
charge-ordering transition temperature decreases with increasing current. The
electroresistive ratio, defined as r0.5/rI where r0.5 is the resistivity at a
current of 0.5 mA and rI the resistivity at a given applied current, I, varies
markedly with temperature and the value of I. Thermal hysteresis observed in
Nd0.5Ca0.5MnO3 and Pr0.6Ca0.4MnO3 at the insulator-metal transition indicates
that the transition is first-order. The current-induced changes are comparable
to those induced by magnetic fields, and the insulator-metal transition in
Pr0.6Ca0.4MnO3 is accordingly associated with a larger drop in resistivity.Comment: 12 pages, 3 figures, first submitted to submitted to J. Phys. D;
applied physics on 18th march 200
Energy transfer, pressure tensor and heating of kinetic plasma
Kinetic plasma turbulence cascade spans multiple scales ranging from
macroscopic fluid flow to sub-electron scales. Mechanisms that dissipate large
scale energy, terminate the inertial range cascade and convert kinetic energy
into heat are hotly debated. Here we revisit these puzzles using fully kinetic
simulation. By performing scale-dependent spatial filtering on the Vlasov
equation, we extract information at prescribed scales and introduce several
energy transfer functions. This approach allows highly inhomogeneous energy
cascade to be quantified as it proceeds down to kinetic scales. The pressure
work, , can
trigger a channel of the energy conversion between fluid flow and random
motions, which is a collision-free generalization of the viscous dissipation in
collisional fluid. Both the energy transfer and the pressure work are strongly
correlated with velocity gradients.Comment: 28 pages, 10 figure
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