765 research outputs found
Heat Transfer and Flow Characteristics of an Oblique Turbulent Impinging Jet Within Confined Walls,”
Monte Carlo study of Si(111) homoepitaxy
An attempt is made to simulate the homoepitaxial growth of a Si(111) surface
by the kinetic Monte Carlo method in which the standard Solid-on-Solid model
and the planar model of the (7x7) surface reconstruction are used in
combination.
By taking account of surface reconstructions as well as atomic deposition and
migrations, it is shown that the effect of a coorparative stacking
transformation is necessary for a layer growth.Comment: 4 pages, 5 figures. For Fig.1 of this article, please see Fig.2 of
Phys.Rev. B56, 3583 (1997). To appear in Phys.Rev.B. (June 1998
Structure analysis of the Ga-stabilized GaAs(001)-c(8x2) surface at high temperatures
Structure of the Ga-stabilized GaAs(001)-c(8x2) surface has been studied
using rocking-curve analysis of reflection high-energy electron diffraction
(RHEED). The c(8x2) structure emerges at temperatures higher than 600C, but is
unstable with respect to the change to the (2x6)/(3x6) structure at lower
temperatures. Our RHEED rocking-curve analysis at high temperatures revealed
that the c(8x2) surface has the structure which is basically the same as that
recently proposed by Kumpf et al. [Phys. Rev. Lett. 86, 3586 (2001)]. We found
that the surface atomic configurations are locally fluctuated at high
temperatures without disturbing the c(8x2) periodicity.Comment: 14 pages, 4 figures, 1 tabl
Reduction techniques of the back gate effect in the SOI Pixel Detector
We have fabricated monolithic pixel sensors in 0.2 μm Silicon-On-Insulator (SOI) CMOS technology, consisting of a thick sensor layer and a thin circuit layer with an insulating buried-oxide, which has many advantages. However, it has been found that the applied electric field in the sensor layer also affects the transistor operation in the adjacent circuit layer. This limits the applicable sensor bias well below the full depletion voltage. To overcome this, we performed a TCAD simulation and added an additional p-well (buried pwell) in the SOI process. Designs and preliminary results are presented
Magic Islands and Barriers to Attachment: A Si/Si(111)7x7 Growth Model
Surface reconstructions can drastically modify growth kinetics during initial
stages of epitaxial growth as well as during the process of surface
equilibration after termination of growth. We investigate the effect of
activation barriers hindering attachment of material to existing islands on the
density and size distribution of islands in a model of homoepitaxial growth on
Si(111)7x7 reconstructed surface. An unusual distribution of island sizes
peaked around "magic" sizes and a steep dependence of the island density on the
growth rate are observed. "Magic" islands (of a different shape as compared to
those obtained during growth) are observed also during surface equilibration.Comment: 4 pages including 5 figures, REVTeX, submitted to Physical Review
Status and overview of development of the Silicon Pixel Detector for the PHENIX experiment at the BNL RHIC
We have developed a silicon pixel detector to enhance the physics
capabilities of the PHENIX experiment. This detector, consisting of two layers
of sensors, will be installed around the beam pipe at the collision point and
covers a pseudo-rapidity of | \eta | < 1.2 and an azimuth angle of | \phi | ~
2{\pi}. The detector uses 200 um thick silicon sensors and readout chips
developed for the ALICE experiment. In order to meet the PHENIX DAQ readout
requirements, it is necessary to read out 4 readout chips in parallel. The
physics goals of PHENIX require that radiation thickness of the detector be
minimized. To meet these criteria, the detector has been designed and
developed. In this paper, we report the current status of the development,
especially the development of the low-mass readout bus and the front-end
readout electronics.Comment: 9 pages, 8 figures and 1 table in DOCX (Word 2007); PIXEL 2008
workshop proceedings, will be published in the Proceedings Section of
JINST(Journal of Instrumentation
Sector logic implementation for the ATLAS endcap level-1 muon trigger
We present development of the Sector Logic for the ATLAS endcap Level-1 (LVL1) muon trigger. The muon tracks from the interaction point (IP) are bent by the magnetic fields induced by the ATLAS toroidal magnets. The Sector Logic reconstructs three dimensional muon tracks with six levels of transverse momentum (pT) by combining two sets (R-Z and φ-Z) of information from the Thin Gap Chamber (TGC) detectors. Then, it selects two highest pT tracks in each trigger sector. The Sector Logic module is designed in pipelined structure to achieve no-dead-time operation and shorter latency. Look-Up-Tables (LUTs) are used so that any pT threshold level can be set. To achieve these, we adopted SRAM embedded type FPGA devices. The design and its performance are given in this presentation
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