11,462 research outputs found
Investigation of thin n-in-p planar pixel modules for the ATLAS upgrade
In view of the High Luminosity upgrade of the Large Hadron Collider (HL-LHC),
planned to start around 2023-2025, the ATLAS experiment will undergo a
replacement of the Inner Detector. A higher luminosity will imply higher
irradiation levels and hence will demand more ra- diation hardness especially
in the inner layers of the pixel system. The n-in-p silicon technology is a
promising candidate to instrument this region, also thanks to its
cost-effectiveness because it only requires a single sided processing in
contrast to the n-in-n pixel technology presently employed in the LHC
experiments. In addition, thin sensors were found to ensure radiation hardness
at high fluences. An overview is given of recent results obtained with not
irradiated and irradiated n-in-p planar pixel modules. The focus will be on
n-in-p planar pixel sensors with an active thickness of 100 and 150 um recently
produced at ADVACAM. To maximize the active area of the sensors, slim and
active edges are implemented. The performance of these modules is investigated
at beam tests and the results on edge efficiency will be shown
ATLAS IBL Pixel Upgrade
The upgrade for ATLAS detector will undergo different phase towards
super-LHC. The first upgrade for the Pixel detector will consist of the
construction of a new pixel layer which will be installed during the first
shutdown of the LHC machine (LHC phase-I upgrade). The new detector, called
Insertable B-Layer (IBL), will be inserted between the existing pixel detector
and a new (smaller radius) beam-pipe at a radius of 3.3 cm. The IBL will
require the development of several new technologies to cope with increase of
radiation or pixel occupancy and also to improve the physics performance which
will be achieved by reducing the pixel size and of the material budget. Three
different promising sensor technologies (planar-Si, 3D-Si and diamond) are
currently under investigation for the pixel detector. An overview of the
project with particular emphasis on pixel module is presented in this paper.Comment: 3 pages, 3 figures, presented at the 12th Topical Seminar on
Innovative Particle and Radiation Detectors (IPRD10) 7 - 10 June 2010, Siena
(IT). Accepted by Nuclear Physics B (Proceedings Supplements) (2011
SPIDER X - Environmental effects in central and satellite early-type galaxies through the stellar fossil record
A detailed analysis of how environment affects the star formation history of
early-type galaxies (ETGs) is undertaken via high signal to noise ratio stacked
spectra obtained from a sample of 20,977 ETGs (morphologically selected) from
the SDSS-based SPIDER survey. Two major parameters are considered for the
study: the central velocity dispersion (sigma), which relates to local drivers
of star formation, and the mass of the host halo, which relates to
environment-related effects. In addition, we separate the sample between
centrals (the most massive galaxy in a halo) and satellites. We derive trends
of age, metallicity, and [alpha/Fe] enhancement, with sigma. We confirm that
the major driver of stellar population properties in ETGs is velocity
dispersion, with a second-order effect associated to the central/satellite
nature of the galaxy. No environmental dependence is detected for satellite
ETGs, except at low sigma - where satellites in groups or in the outskirts of
clusters tend to be younger than those in the central regions of clusters. In
contrast, the trends for centrals show a significant dependence on halo mass.
Central ETGs in groups (i.e. with a halo mass >10^12.5 M_Sun) have younger
ages, lower [alpha/Fe], and higher internal reddening, than "isolated" systems
(i.e. centrals residing in low-mass, <10^12.5 M_Sun, halos). Our findings imply
that central ETGs in groups formed their stellar component over longer time
scales than "isolated" centrals, mainly because of gas-rich interactions with
their companion galaxies.Comment: 22 pages, 19 figures, accepted for publication in MNRA
Crónica de las I Jornadas Internacionales de Prehistoria Ciudad de La Laguna. Antiguo Convento de Santo Domingo, La Laguna - Tenerife, 5, 6 y 7 de noviembre de 2008.
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
High resolution radio study of the Pulsar Wind Nebula within the Supernova Remnant G0.9+0.1
We have conducted a radio study at 3.6, 6 and 20 cm using ATCA and VLA and
reprocessed XMM-Newton and Chandra data of the pulsar wind nebula (PWN) in the
supernova remnant (SNR) G0.9+0.1. The new observations revealed that the
morphology and symmetry suggested by Chandra observations (torus and jet-like
features) are basically preserved in the radio range in spite of the rich
structure observed in the radio emission of this PWN, including several arcs,
bright knots, extensions and filaments. The reprocessed X-ray images show for
the first time that the X-ray plasma fills almost the same volume as the radio
PWN. Notably the X-ray maximum does not coincide with the radio maximum and the
neutron star candidate CXOU J174722.8-280915 lies within a small depression in
the radio emission. From the new radio data we have refined the flux density
estimates, obtaining S(PWN) ~ 1.57 Jy, almost constant between 3.6 and 20 cm.
For the whole SNR (compact core and shell), a flux density S(at 20 cm)= 11.5 Jy
was estimated. Based on the new and the existing 90 cm flux density estimates,
we derived alpha(PWN)=-0.18+/-0.04 and alpha(shell)=-0.68+/- 0.07. From the
combination of the radio data with X-ray data, a spectral break is found near
nu ~ 2.4 x 10^(12) Hz. The total radio PWN luminosity is L(radio)=1.2 x 10^(35)
erg s^(-1) when a distance of 8.5 kpc is adopted. By assuming equipartition
between particle and magnetic energies, we estimate a nebular magnetic field B
= 56 muG. The associated particle energy turns out to be U(part)=5 x 10^(47)
erg and the magnetic energy U(mag)=2 x 10^(47) erg. Based on an empirical
relation between X-ray luminosity and pulsar energy loss rate, and the
comparison with the calculated total energy, a lower limit of 1100 yr is
derived for the age of this PWN.Comment: 10 pages,8 figures, accepted for publication in A&A, June 13 200
Wireless communication, identification and sensing technologies enabling integrated logistics: a study in the harbor environment
In the last decade, integrated logistics has become an important challenge in
the development of wireless communication, identification and sensing
technology, due to the growing complexity of logistics processes and the
increasing demand for adapting systems to new requirements. The advancement of
wireless technology provides a wide range of options for the maritime container
terminals. Electronic devices employed in container terminals reduce the manual
effort, facilitating timely information flow and enhancing control and quality
of service and decision made. In this paper, we examine the technology that can
be used to support integration in harbor's logistics. In the literature, most
systems have been developed to address specific needs of particular harbors,
but a systematic study is missing. The purpose is to provide an overview to the
reader about which technology of integrated logistics can be implemented and
what remains to be addressed in the future
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