| 1. |
- Abdesselam, A., et al.
(författare)
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Engineering for the ATLAS SemiConductor Tracker (SCT) end-cap
- 2008
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- The ATLAS SemiConductor Tracker (SCT) is a silicon-strip tracking detector which forms part of the ATLAS inner detector. The SCT is designed to track charged particles produced in proton-proton collisions at the Large Hadron Collider (LHC) at CERN at an energy of 14 TeV. The tracker is made up of a central barrel and two identical end-caps. The barrel contains 2112 silicon modules, while each end-cap contains 988 modules. The overall tracking performance depends not only on the intrinsic measurement precision of the modules but also on the characteristics of the whole assembly, in particular, the stability and the total material budget. This paper describes the engineering design and construction of the SCT end-caps, which are required to support mechanically the silicon modules, supply services to them and provide a suitable environment within the inner detector. Critical engineering choices are highlighted and innovative solutions are presented - these will be of interest to other builders of large-scale tracking detectors. The SCT end-caps will be fully connected at the start of 2008. Further commissioning will continue, to be ready for proton-proton collision data in 2008.
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| 2. |
- Abdesselam, A., et al.
(författare)
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The ATLAS semiconductor tracker end-cap module
- 2007
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 575:3, s. 353-389
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Tidskriftsartikel (refereegranskat)abstract
- The challenges for the tracking detector systems at the LHC are unprecedented in terms of the number of channels, the required read-out speed and the expected radiation levels. The ATLAS Semiconductor Tracker. (SCT) end-caps have a total of about 3 million electronics channels each reading out every 25 ns into its own on-chip 3.3 mu s buffer. The highest anticipated dose after 10 years operation is 1.4x10(14) cm(-2) in units of 1 MeV neutron equivalent (assuming the damage factors scale with the non-ionising energy loss). The forward tracker has 1976 double-sided modules, mostly of area similar to 70 cm(2), each having 2 x 768 strips read out by six ASICs per side. The requirement to achieve an average perpendicular radiation length of 1.5% X-0, while coping with up to 7 W dissipation per module (after irradiation), leads to stringent constraints on the thermal design. The additional requirement of 1500e(-) equivalent noise charge (ENC) rising to only 1800e(-) ENC after irradiation, provides stringent design constraints on both the high-density Cu/Polyimide flex read-out circuit and the ABCD3TA read-out ASICs. Finally, the accuracy of module assembly must not compromise the 16 mu m (r phi) resolution perpendicular to the strip directions or 580 mu m radial resolution coming from the 40 mrad front-back stereo angle. A total of 2210 modules were built to the tight tolerances and specifications required for the SCT. This was 234 more than the 1976 required and represents a yield of 93%. The component flow was at times tight, but the module production rate of 40-50 per week was maintained despite this. The distributed production was not found to be a major logistical problem and it allowed additional flexibility to take advantage of where the effort was available, including any spare capacity, for building the end-cap modules. The collaboration that produced the ATLAS SCT end-cap modules kept in close contact at all times so that the effects of shortages or stoppages at different sites could be rapidly resolved.
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| 3. |
- Ho, Gordon, et al.
(författare)
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Management of Arrhythmias and Cardiac Implantable Electronic Devices in Patients With Left Ventricular Assist Devices
- 2018
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Ingår i: JACC: Clinical Electrophysiology. - : Elsevier BV. - 2405-500X. ; 4:7, s. 847-859
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Tidskriftsartikel (refereegranskat)abstract
- For patients with end-stage heart failure, the use of mechanical circulatory support has increased in the last decade due to improved outcomes with durable left ventricular assist devices. The management of these complex patients requires coordinated care by a multidisciplinary team including cardiac electrophysiologists because atrial and ventricular arrhythmias are prevalent in this population. There have been an increasing number of studies that attempt to address issues regarding arrhythmia management in patients with left ventricular assist devices. The purpose of this review is to provide electrophysiologists with an evidence-based approach to manage a broad spectrum of arrhythmia issues in these patients.
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| 4. |
- Källner, Nils, et al.
(författare)
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Predictors of rate-adaptive pacing in patients implanted with implantable cardioverter-defibrillator and subsequent differential clinical outcomes
- 2019
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Ingår i: Journal of Interventional Cardiac Electrophysiology. - : SPRINGER. - 1383-875X .- 1572-8595. ; 55:1, s. 83-91
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Tidskriftsartikel (refereegranskat)abstract
- PurposePatients with severe cardiomyopathy often have chronotropic incompetence, which is predominantly managed by activating rate-adaptive pacing in patients implanted with an implantable cardioverter-defibrillator (ICD) capable of atrial pacing. The purpose of this study was to determine predictors of rate-adaptive pacing activation, the cumulative incidence of activation, and the association of rate-adaptive pacing activation with subsequent clinical outcomes in an ICD population.MethodsThe authors evaluated 228 patients implanted with an ICD between 2011 and 2015. Multivariable logistic regression was used to evaluate predictors of rate-adaptive pacing activation. Cox proportional-hazards regression was used to examine associations of rate-adaptive pacing activation and clinical outcomes.ResultsRate-adaptive pacing was turned on in 38.5% (n=88) of patients during follow-up. Several statistically significant predictors of rate-adaptive pacing activation were found, particularly previous atrial fibrillation (odds ratio [OR]=8.27, 95% confidence interval [CI]=2.96-23.06, pamp;lt;0.001), previous myocardial infarction (OR=4.17, 95% CI=1.38-12.58, p=0.01), and non-ischemic cardiomyopathy (OR=3.83, 95% CI=1.22-12.00, p=0.02). In multivariable adjusted analyses, rate-adaptive pacing activation within 30days of implantation was not associated with the risk of device therapy for tachyarrhythmias (hazard ratio [HR]=1.52, 95% CI=0.71-3.28, p=0.29), atrial fibrillation (HR=1.42, 95% CI=0.71-2.87, p=0.32), HF re-admission (HR=1.39, 95% CI=0.80-2.43, p=0.25), nor all-cause mortality (HR=2.34, 95% CI=0.80-6.84, p=0.12).ConclusionsDuring follow-up, more than one in three HF patients implanted with an ICD developed the need for rate-adaptive pacing. Atrial fibrillation, prior myocardial infarction, and non-ischemic cardiomyopathy were statistically significant baseline clinical predictors of rate-adaptive pacing activation. Rate-adaptive pacing activation was not associated with subsequent adverse clinical outcomes.
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