3,453 research outputs found
TRT Alignment For SR1 Cosmics and Beyond
We present an algorithm for the alignment of the ATLAS Inner Detector, developed for the analysis of cosmics data taken with the ID barrel in SR1 in the summer of 2006. Our results include a comparison of the relative SCT-TRT alignment with survey measurements, a study of the alignment of SCT and TRT module positions and TRT module deformations, and a comparison of the `local' and `global' methods for alignment
A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test
Alignment of LHCb tracking stations with tracks fitted with a Kalman filter
The LHCb detector, operating at the Large Hadron Collider at CERN, is a single arm spectrometer optimized for the detection of the forward b anti-b production for b physics studies. The reconstruction of vertices and tracks is done by silicon micro-strips and gaseous straw-tube based detectors. In order to achieve good mass resolution for resonances the tracking detectors should be aligned to a precision of the order of ten microns. A software framework has been developed to achieve these goals and has been tested in various configurations. After a description of the software, we present alignment results and show in particular for the first time that a global solving for alignment using a locally parameterized track trajectory can be achieved
First studies of T-station alignment with simulated data
The alignment of the tracking stations using tracks fitted using standard LHCb track fit is studied. The procedure is presented together with two examples using simulated data. The first scenario presents the alignment of the IT and OT layers using beam-gas events at 450~GeV with no magnetic field. The second scenario is the alignment of the OT layers and IT boxes, layers and ladders with magnet-on data using minimum bias events at nominal energy. The results are validated by refitting J/ tracks using the misaligned geometry compared to the re-aligned case as well as the default. It is shown that after alignment the J mass resolution is degraded by at most 3~\%
Improved performance of the LHCb Outer Tracker in LHC Run 2
The LHCb Outer Tracker is a gaseous detector covering an area of with 12 double layers of straw tubes. The performance of the detector is
presented based on data of the LHC Run 2 running period from 2015 and 2016.
Occupancies and operational experience for data collected in , pPb and
PbPb collisions are described. An updated study of the ageing effects is
presented showing no signs of gain deterioration or other radiation damage
effects. In addition several improvements with respect to LHC Run 1 data taking
are introduced. A novel real-time calibration of the time-alignment of the
detector and the alignment of the single monolayers composing detector modules
are presented, improving the drift-time and position resolution of the detector
by 20\%. Finally, a potential use of the improved resolution for the timing of
charged tracks is described, showing the possibility to identify low-momentum
hadrons with their time-of-flight.Comment: 29 pages, 20 figures, minor changes to match the published versio
Aging Studies for the Large Honeycomb Drift Tube System of the Outer Tracker of HERA-B
The HERA-B Outer Tracker consists of drift tubes folded from polycarbonate
foil and is operated with Ar/CF4/CO2 as drift gas. The detector has to stand
radiation levels which are similar to LHC conditions. The first prototypes
exposed to radiation in HERA-B suffered severe radiation damage due to the
development of self-sustaining currents (Malter effect). In a subsequent
extended R&D program major changes to the original concept for the drift tubes
(surface conductivity, drift gas, production materials) have been developed and
validated for use in harsh radiation environments. In the test program various
aging effects (like Malter currents, gain loss due to anode aging and etching
of the anode gold surface) have been observed and cures by tuning of operation
parameters have been developed.Comment: 14 pages, 6 figures, to be published in the Proceedings of the
International Workshop On Aging Phenomena In Gaseous Detectors, 2-5 Oct 2001,
Hamburg, German
Type D Personality Associated With Increased Risk for Mortality in Adults With Congenital Heart Disease
Background Type D personality has been previously shown to increase the risk for mortality in patients with acquired heart disease.ObjectiveWe aimed to compare mortality in adult patients with congenital heart disease (CHD) with and without type D.Methods Survival was assessed using prospective data from the Dutch national Congenital Corvitia registry for adults with CHD. Patients were randomly selected from the registry and characterized at inclusion in 2009 for the presence of type D using the DS14 questionnaire.Results One thousand fifty-five patients, with 484 (46%) males, a mean (SD) age of 41 (14) years, 613 (58%) having mild CHD, 348 (33%) having moderate CHD, and 94 (9%) having severe CHD, were included. Type D personality was present in 225 patients (21%). Type D was associated with an increased risk for all-cause mortality independent of age, sex, New York Heart Association class, number of prescribed medications, depression, employment status, and marital status (hazard ratio, 1.94; 95% confidence interval, 1.05–3.57; P = .033).Conclusion Type D personality was associated with an increased risk for all-cause mortality in adult patients with CHD
The Outer Tracker Detector of the HERA-B Experiment Part I: Detector
The HERA-B Outer Tracker is a large system of planar drift chambers with
about 113000 read-out channels. Its inner part has been designed to be exposed
to a particle flux of up to 2.10^5 cm^-2 s^-1, thus coping with conditions
similar to those expected for future hadron collider experiments. 13
superlayers, each consisting of two individual chambers, have been assembled
and installed in the experiment. The stereo layers inside each chamber are
composed of honeycomb drift tube modules with 5 and 10 mm diameter cells.
Chamber aging is prevented by coating the cathode foils with thin layers of
copper and gold, together with a proper drift gas choice. Longitudinal wire
segmentation is used to limit the occupancy in the most irradiated detector
regions to about 20 %. The production of 978 modules was distributed among six
different laboratories and took 15 months. For all materials in the fiducial
region of the detector good compromises of stability versus thickness were
found. A closed-loop gas system supplies the Ar/CF4/CO2 gas mixture to all
chambers. The successful operation of the HERA-B Outer Tracker shows that a
large tracker can be efficiently built and safely operated under huge radiation
load at a hadron collider.Comment: 28 pages, 14 figure
The Outer Tracker Detector of the HERA-B Experiment. Part II: Front-End Electronics
The HERA-B Outer Tracker is a large detector with 112674 drift chamber
channels. It is exposed to a particle flux of up to 2x10^5/cm^2/s thus coping
with conditions similar to those expected for the LHC experiments. The
front-end readout system, based on the ASD-8 chip and a customized TDC chip, is
designed to fulfil the requirements on low noise, high sensitivity, rate
tolerance, and high integration density. The TDC system is based on an ASIC
which digitizes the time in bins of about 0.5 ns within a total of 256 bins.
The chip also comprises a pipeline to store data from 128 events which is
required for a deadtime-free trigger and data acquisition system. We report on
the development, installation, and commissioning of the front-end electronics,
including the grounding and noise suppression schemes, and discuss its
performance in the HERA-B experiment
Diagnosis of alpha-1-antitrypsin deficiency in bleeding disorder-related neonatal death
Alpha-1-antitrypsin (AAT) deficiency is a rare genetic disorder characterized by hepatitis in neonates, childhood and adulthood (protease inhibitor (PI)*ZZ) and emphysema with or without hepatitis (PI*ZZ)/(PI*SS,SZ or null) in adulthood. We report the case of a female neonate born at 40 weeks of gestation who presented with vitamin K deficiency-related intracranial bleeding and cholestasis of which she died at 28 days of age. At autopsy, the infant was found to have intracranial bleeding, hepatomegaly, and cholestasis with paucity of bile ducts in the liver. Small periodic acid-Schiff diastase positive intrahepatic granules and positive staining with antibodies against AAT protein suggested an AAT deficiency. AAT is a glycoprotein that has a protease inhibitor function. Its deficiency can be the result of various point mutations in Serpin 1 located on chromosome 14. The diagnosis AAT deficiency was confirmed by mutation analysis showing the PI*ZZ genotype in the neonate. In conclusion, AAT deficiency is a rare genetic disorder that can lead to a serious bleeding disorder in the neonatal period if not recognised on time. Pathological diagnosis together with verifying molecular analysis can be used to identify index patients
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