4,495 research outputs found
Pixel Detectors for Tracking and their Spin-off in Imaging Applications
To detect tracks of charged particles close to the interaction point in high
energy physics experiments of the next generation colliders, hybrid pixel
detectors, in which sensor and read-out IC are separate entities, constitute
the present state of the art in detector technology. Three of the LHC detectors
as well as the BTeV detector at the Tevatron will use vertex detectors based on
this technology. A development period of almost 10 years has resulted in pixel
detector modules which can stand the extreme rate and timing requirements as
well as the very harsh radiation environment at the LHC for its full life time
and without severe compromises in performance. From these developments a number
of different applications have spun off, most notably for biomedical imaging.
Beyond hybrid pixels, a number of trends and possibilities with yet improved
performance in some aspects have appeared and presently developed to greater
maturity. Among them are monolithic or semi-monolithic pixel detectors which do
not require complicated hybridization but come as single sensor/IC entities.
The present state in hybrid pixel detector development for the LHC experiments
as well as for some imaging applications is reviewed and new trends towards
monolithic or semi-monolithic pixel devices are summarized.Comment: 24 pages, 16 figure
Design and Prototype Performance of the ATLAS Pixel Detector
The ATLAS experiment at the LHC will have three barrel and two times five disk layers of silicon pixel detectors as the innermost elements of the Inner Tracking Detector. the detctor is built adopting the hybrid pixel technology in which 16 highly permormant FE chips are connected to a silicon sensor by means of the bump and flip-chip technique. Owing to the high bunch crossing rate of 40 MHz at the LHC and the high particle fluences a sophisticated design concept is employed. The projet is presently entering the pre-production phase. The various aspects of the detector, the expected performance and the so far obtained prototype results are presented
PIXEL 2010 - a Resume
The Pixel 2010 conference focused on semiconductor pixel detectors for
particle tracking/vertexing as well as for imaging, in particular for
synchrotron light sources and XFELs. The big LHC hybrid pixel detectors have
impressively started showing their capabilities. X-ray imaging detectors, also
using the hybrid pixel technology, have greatly advanced the experimental
possibilities for diiffraction experiments. Monolithic or semi-monolithic
devices like CMOS active pixels and DEPFET pixels have now reached a state such
that complete vertex detectors for RHIC and superKEKB are being built with
these technologies. Finally, new advances towards fully monolithic active pixel
detectors, featuring full CMOS electronics merged with efficient signal charge
collection, exploiting standard CMOS technologies, SOI and/or 3D integration,
show the path for the future. This r\'esum\'e attempts to extract the main
statements of the results and developments presented at this conference.Comment: 8 pages, 19 figures, conference summar
Prospects for the Measurement of the Structure of the Coupling of a Higgs Boson to Weak Gauge Bosons in Weak Boson Fusion with the ATLAS Detector
The prospects for the measurement of the tensor structure of the vertex between a standard model Higgs boson and two weak gauge bosons using the distribution of the azimuthal angles between the two tagging jets in the weak boson fusion channel are studied in a Monte Carlo analysis using the fast simulation of the ATLAS detector. The decay channels , at GeV and at GeV are used in the analysis. For a standard model Higgs boson it is found that purely anomalous couplings are expected to be excluded at a confidence level corresponding to 2\, or more at GeV and more than 5\, at GeV from fb of data. With a value of 1 roughly reproducing the standard model cross section for a purely anomalous coupling, the standard deviation in a measurement of a contribution of a CP even anomalous coupling in addition to the standard model coupling is estimated to be 0.20 at GeV and 0.08 at GeV
Readout Concepts for DEPFET Pixel Arrays
Field effect transistors embedded into a depleted silicon bulk (DEPFETs) can
be used as the first amplifying element for the detection of small signal
charges deposited in the bulk by ionizing particles, X-ray photons or visible
light. Very good noise performance at room temperature due to the low
capacitance of the collecting electrode has been demonstrated. Regular two
dimensional arrangements of DEPFETs can be read out by turning on individual
rows and reading currents or voltages in the columns. Such arrangements allow
the fast, low power readout of larger arrays with the possibility of random
access to selected pixels. In this paper, different readout concepts are
discussed as they are required for arrays with incomplete or complete clear and
for readout at the source or the drain. Examples of VLSI chips for the steering
of the gate and clear rows and for reading out the columns are presented.Comment: 8 pages, 9 figures, submitted to Nucl. Instr. and Methods as
proceedings of the 9th European Symposium on Semiconductor Detectors, Elmau,
June 23-27, 200
Status of a DEPFET pixel system for the ILC vertex detector
We have developed a prototype system for the ILC vertex detector based on
DEPFET pixels. The system operates a 128x64 matrix (with ~35x25 square micron
large pixels) and uses two dedicated microchips, the SWITCHER II chip for
matrix steering and the CURO II chip for readout. The system development has
been driven by the final ILC requirements which above all demand a detector
thinned to 50 micron and a row wise read out with line rates of 20MHz and more.
The targeted noise performance for the DEPFET technology is in the range of
ENC=100 e-. The functionality of the system has been demonstrated using
different radioactive sources in an energy range from 6 to 40keV. In recent
test beam experiments using 6GeV electrons, a signal-to-noise ratio of S/N~120
has been achieved with present sensors being 450 micron thick. For improved
DEPFET systems using 50 micron thin sensors in future, a signal-to-noise of 40
is expected.Comment: Invited poster at the International Symposium on the Development of
Detectors for Particle, AstroParticle and Synchrotron Radiation Experiments,
Stanford CA (SNIC06) 6 pages, 12 eps figure
First observation of electrons in the ATLAS detector
This poster shows approved plots from https://twiki.cern.ch/twiki/bin/view/Atlas/ElectronGammaApprovedCosmicPlots and will be presented at the Hadron Collider Physics Symposium 16th -20th November 2009 in Evian
Test beam Characterizations of 3D Silicon Pixel detectors
3D silicon detectors are characterized by cylindrical electrodes
perpendicular to the surface and penetrating into the bulk material in contrast
to standard Si detectors with planar electrodes on its top and bottom. This
geometry renders them particularly interesting to be used in environments where
standard silicon detectors have limitations, such as for example the radiation
environment expected in an LHC upgrade. For the first time, several 3D sensors
were assembled as hybrid pixel detectors using the ATLAS-pixel front-end chip
and readout electronics. Devices with different electrode configurations have
been characterized in a 100 GeV pion beam at the CERN SPS. Here we report
results on unirradiated devices with three 3D electrodes per 50 x 400 um2 pixel
area. Full charge collection is obtained already with comparatively low bias
voltages around 10 V. Spatial resolution with binary readout is obtained as
expected from the cell dimensions. Efficiencies of 95.9% +- 0.1 % for tracks
parallel to the electrodes and of 99.9% +- 0.1 % at 15 degrees are measured.
The homogeneity of the efficiency over the pixel area and charge sharing are
characterized.Comment: 5 pages, 7 figure
Concept, realization and characterization of serially powered pixel modules
We prove and demonstrate here for the example of the large scale pixel detector of ATLAS that Serial Powering of pixel modules is a viable alternative and that has been devised and implemented for ATLAS pixel modules using dedicated on-chip voltage regulators and modified flex hybrids circuits. The equivalent of a pixel ladder consisting of six serially powered pixel modules with about 0.3Mpixels has been built and the performance with respect to noise and threshold stability and operation failures has been studied. We believe that Serial Powering in general will be necessary for future large scale tracking detectors
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