669 research outputs found
Performance of novel silicon n-in-p planar Pixel Sensors
The performance of novel n-in-p planar pixel detectors, designed for future
upgrades of the ATLAS Pixel system is presented. The n-in-p silicon sensors
technology is a promising candidate for the pixel upgrade thanks to its
radiation hardness and cost effectiveness, that allow for enlarging the area
instrumented with pixel detectors. The n-in-p modules presented here are
composed of pixel sensors produced by CiS connected by bump-bonding to the
ATLAS readout chip FE-I3. The characterization of these devices has been
performed before and after irradiation up to a fluence of 5 x 10**15 1 MeV neq
cm-2 . Charge collection measurements carried out with radioactive sources have
proven the functioning of this technology up to these particle fluences. First
results from beam test data with a 120 GeV/c pion beam at the CERN-SPS are also
discussed, demonstrating a high tracking efficiency of (98.6 \pm 0.3)% and a
high collected charge of about 10 ke for a device irradiated at the maximum
fluence and biased at 1 kV.Comment: Preprint submitted to Nuclear Instruments and Methods A. 7 pages, 13
figure
Surface Mapping of Earth-like Exoplanets using Single Point Light Curves
Spatially resolving exoplanet features from single-point observations is essential for evaluating the potential habitability of exoplanets. The ultimate goal of this protocol is to determine whether these planetary worlds harbor geological features and/or climate systems. We present a method of extracting information from multi-wavelength single-point light curves and retrieving surface maps. It uses singular value decomposition (SVD) to separate sources that contribute to light curve variations and infer the existence of partially cloudy climate systems. Through analysis of the time series obtained from SVD, physical attributions of principal components (PCs) could be inferred without assumptions of any spectral properties. Combining with viewing geometry, it is feasible to reconstruct surface maps if one of the PCs are found to contain surface information. Degeneracy originated from convolution of the pixel geometry and spectrum information determines the quality of reconstructed surface maps, which requires the introduction of regularization. For the purpose of demonstrating the protocol, multi-wavelength light curves of Earth, which serves as a proxy exoplanet, are analyzed. Comparison between the results and the ground truth is presented to show the performance and limitation of the protocol. This work provides a benchmark for future generalization of exoplanet applications
Level-1 pixel based tracking trigger algorithm for LHC upgrade
The Pixel Detector is the innermost detector of the tracking system of the
Compact Muon Solenoid (CMS) experiment at CERN Large Hadron Collider (LHC). It
precisely determines the interaction point (primary vertex) of the events and
the possible secondary vertexes due to heavy flavours ( and quarks); it
is part of the overall tracking system that allows reconstructing the tracks of
the charged particles in the events and combined with the magnetic field to
measure their impulsion. The pixel detector allows measuring the tracks in the
region closest to the interaction point. The Level-1 (real-time) pixel based
tracking trigger is a novel trigger system that is currently being studied for
the LHC upgrade. An important goal is developing real-time track reconstruction
algorithms able to cope with very high rates and high flux of data in a very
harsh environment. The pixel detector has an especially crucial role in
precisely identifying the primary vertex of the rare physics events from the
large pile-up (PU) of events. The goal of adding the pixel information already
at the real-time level of the selection is to help reducing the total level-1
trigger rate while keeping an high selection capability. This is quite an
innovative and challenging objective for the experiments upgrade for the High
Luminosity LHC (HL-LHC). The special case here addressed is the CMS experiment.
This document describes exercises focusing on the development of a fast pixel
track reconstruction where the pixel track matches with a Level-1 electron
object using a ROOT-based simulation framework.Comment: Submitted to JINST; 12 pages, 10 figures, Contribution to the JINST
proceedings for the INFIERI2014 School in Paris, France, July 14-25, 201
The ATLAS Pixel Project
The ATLAS experiment, at the Large Hadron Collider, will incorporate discrete, high-resolution tracking sub-systems in the form of segmented silicon detectors with 40MHz radiation-hard readout electronics. In the region closest to the pp interaction point, the thin silicon tiles will be segmented into a pixel geometry providing two-dimensional space-point information. The current status of the ATLAS pixel project will be presented with an emphasis on the performance of the front-end electronics and prototype sensors
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