2,882 research outputs found
Nanoflare Evidence from Analysis of the X-Ray Variability of an Active Region Observed with Hinode/XRT
The heating of the solar corona is one of the big questions in astrophysics.
Rapid pulses called nanoflares are among the best candidate mechanisms. The
analysis of the time variability of coronal X-ray emission is potentially a
very useful tool to detect impulsive events. We analyze the small-scale
variability of a solar active region in a high cadence Hinode/XRT observation.
The dataset allows us to detect very small deviations of emission fluctuations
from the distribution expected for a constant rate. We discuss the deviations
in the light of the pulsed-heating scenario.Comment: 6 pages, 4 figure
Production and Characterisation of SLID Interconnected n-in-p Pixel Modules with 75 Micrometer Thin Silicon Sensors
The performance of pixel modules built from 75 micrometer thin silicon
sensors and ATLAS read-out chips employing the Solid Liquid InterDiffusion
(SLID) interconnection technology is presented. This technology, developed by
the Fraunhofer EMFT, is a possible alternative to the standard bump-bonding. It
allows for stacking of different interconnected chip and sensor layers without
destroying the already formed bonds. In combination with Inter-Chip-Vias (ICVs)
this paves the way for vertical integration. Both technologies are combined in
a pixel module concept which is the basis for the modules discussed in this
paper.
Mechanical and electrical parameters of pixel modules employing both SLID
interconnections and sensors of 75 micrometer thickness are covered. The
mechanical features discussed include the interconnection efficiency, alignment
precision and mechanical strength. The electrical properties comprise the
leakage currents, tuning characteristics, charge collection, cluster sizes and
hit efficiencies. Targeting at a usage at the high luminosity upgrade of the
LHC accelerator called HL-LHC, the results were obtained before and after
irradiation up to fluences of
(1 MeV neutrons).Comment: 16 pages, 22 figure
Thin n-in-p pixel sensors and the SLID-ICV vertical integration technology for the ATLAS upgrade at the HL-LHC
The R&D activity presented is focused on the development of new modules for
the upgrade of the ATLAS pixel system at the High Luminosity LHC (HL-LHC). The
performance after irradiation of n-in-p pixel sensors of different active
thicknesses is studied, together with an investigation of a novel
interconnection technique offered by the Fraunhofer Institute EMFT in Munich,
the Solid-Liquid-InterDiffusion (SLID), which is an alternative to the standard
solder bump-bonding. The pixel modules are based on thin n-in-p sensors, with
an active thickness of 75 um or 150 um, produced at the MPI Semiconductor
Laboratory (MPI HLL) and on 100 um thick sensors with active edges, fabricated
at VTT, Finland. Hit efficiencies are derived from beam test data for thin
devices irradiated up to a fluence of 4e15 neq/cm^2. For the active edge
devices, the charge collection properties of the edge pixels before irradiation
is discussed in detail, with respect to the inner ones, using measurements with
radioactive sources. Beyond the active edge sensors, an additional ingredient
needed to design four side buttable modules is the possibility of moving the
wire bonding area from the chip surface facing the sensor to the backside,
avoiding the implementation of the cantilever extruding beyond the sensor area.
The feasibility of this process is under investigation with the FE-I3 SLID
modules, where Inter Chip Vias are etched, employing an EMFT technology, with a
cross section of 3 um x 10 um, at the positions of the original wire bonding
pads.Comment: Proceedings for Pixel 2012 Conference, submitted to NIM A, 6 page
3D sensors for the HL-LHC
In order to increase its discovery potential, the Large Hadron Collider (LHC)
accelerator will be upgraded in the next decade. The high luminosity LHC
(HL-LHC) period demands new sensor technologies to cope with increasing
radiation fluences and particle rates. The ATLAS experiment will replace the
entire inner tracking detector with a completely new silicon-only system. 3D
pixel sensors are promising candidates for the innermost layers of the Pixel
detector due to their excellent radiation hardness at low operation voltages
and low power dissipation at moderate temperatures. Recent developments of 3D
sensors for the HL-LHC are presented.Comment: 8 pages, 5 figures, International Workshops on Radiation Imaging
Detectors 201
Amiodarone-induced pulmonary toxicity with an excellent response to treatment
Amiodarone is an anti-arrhythmic drug widely used, but its administration can be associated with several adverse side-effects. Among these, amiodarone-induced pulmonary toxicity (APT) occurs in 4-17% of cases and, if not early diagnosed and treated, may evolve towards pulmonary fibrosis and respiratory failure. A 76 years-old-man went to the hospital for accidental trauma. The patient did not report respiratory symptoms but was suffering from atrial fibrillation treated with amiodarone 200 mg/day from three years (cumulative dose >150 gr). HRCT showed ground-glass opacities and nodules in both lungs. The patient underwent fibreoptic bronchoscopy with BAL. Cytologic examination of BALF sediment put in evidence foamy macrophages. The electronic microscopy revealed into the alveolar macrophages "⊠the presence of multilamellar intracytoplasmic bodies and lysosomes, loads of lipid material". LFTs showed a restrictive syndrome and an impairment of DLCO. Amiodarone discontinuation and steroid administration led to the regression of radiological lesions and the recovery of lung function. Patients taking amiodarone can experience APT. They should perform a basal chest x-ray with LFTs before starting therapy. Monitoring could reveal early the pulmonary toxicity, and patients can respond favourably to the treatment
Characterisation of AMS H35 HV-CMOS monolithic active pixel sensor prototypes for HEP applications
Monolithic active pixel sensors produced in High Voltage CMOS (HV-CMOS)
technology are being considered for High Energy Physics applications due to the
ease of production and the reduced costs. Such technology is especially
appealing when large areas to be covered and material budget are concerned.
This is the case of the outermost pixel layers of the future ATLAS tracking
detector for the HL-LHC. For experiments at hadron colliders, radiation
hardness is a key requirement which is not fulfilled by standard CMOS sensor
designs that collect charge by diffusion. This issue has been addressed by
depleted active pixel sensors in which electronics are embedded into a large
deep implantation ensuring uniform charge collection by drift. Very first small
prototypes of hybrid depleted active pixel sensors have already shown a
radiation hardness compatible with the ATLAS requirements. Nevertheless, to
compete with the present hybrid solutions a further reduction in costs
achievable by a fully monolithic design is desirable. The H35DEMO is a large
electrode full reticle demonstrator chip produced in AMS 350 nm HV-CMOS
technology by the collaboration of Karlsruher Institut f\"ur Technologie (KIT),
Institut de F\'isica d'Altes Energies (IFAE), University of Liverpool and
University of Geneva. It includes two large monolithic pixel matrices which can
be operated standalone. One of these two matrices has been characterised at
beam test before and after irradiation with protons and neutrons. Results
demonstrated the feasibility of producing radiation hard large area fully
monolithic pixel sensors in HV-CMOS technology. H35DEMO chips with a substrate
resistivity of 200 cm irradiated with neutrons showed a radiation
hardness up to a fluence of ncm with a hit efficiency of
about 99% and a noise occupancy lower than hits in a LHC bunch
crossing of 25ns at 150V
The design and commissioning of the MICE upstream time-of-flight system
In the MICE experiment at RAL the upstream time-of-flight detectors are used
for particle identification in the incoming muon beam, for the experiment
trigger and for a precise timing (sigma_t ~ 50 ps) with respect to the
accelerating RF cavities working at 201 MHz. The construction of the upstream
section of the MICE time-of-flight system and the tests done to characterize
its individual components are shown. Detector timing resolutions ~50-60 ps were
achieved. Test beam performance and preliminary results obtained with beam at
RAL are reported.Comment: accepted on Nuclear Instruments and Methods
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