| 1. |
- Aad, G., et al.
(author)
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Commissioning of the ATLAS Muon Spectrometer with cosmic rays
- 2010
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In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:3, s. 875-916
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Journal article (peer-reviewed)abstract
- The ATLAS detector at the Large Hadron Collider has collected several hundred million cosmic ray events during 2008 and 2009. These data were used to commission the Muon Spectrometer and to study the performance of the trigger and tracking chambers, their alignment, the detector control system, the data acquisition and the analysis programs. We present the performance in the relevant parameters that determine the quality of the muon measurement. We discuss the single element efficiency, resolution and noise rates, the calibration method of the detector response and of the alignment system, the track reconstruction efficiency and the momentum measurement. The results show that the detector is close to the design performance and that the Muon Spectrometer is ready to detect muons produced in high energy proton-proton collisions.
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| 2. |
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| 3. |
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| 4. |
- Aad, G., et al.
(author)
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Studies of the performance of the ATLAS detector using cosmic-ray muons
- 2011
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In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 71:3
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Journal article (peer-reviewed)abstract
- Muons from cosmic-ray interactions in the atmosphere provide a high-statistics source of particles that can be used to study the performance and calibration of the ATLAS detector. Cosmic-ray muons can penetrate to the cavern and deposit energy in all detector subsystems. Such events have played an important role in the commissioning of the detector since the start of the installation phase in 2005 and were particularly important for understanding the detector performance in the time prior to the arrival of the first LHC beams. Global cosmic-ray runs were undertaken in both 2008 and 2009 and these data have been used through to the early phases of collision data-taking as a tool for calibration, alignment and detector monitoring. These large datasets have also been used for detector performance studies, including investigations that rely on the combined performance of different subsystems. This paper presents the results of performance studies related to combined tracking, lepton identification and the reconstruction of jets and missing transverse energy. Results are compared to expectations based on a cosmic-ray event generator and a full simulation of the detector response.
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| 5. |
- Aad, G., et al.
(author)
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The ATLAS Inner Detector commissioning and calibration
- 2010
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In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:3, s. 787-821
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Journal article (peer-reviewed)abstract
- The ATLAS Inner Detector is a composite tracking system consisting of silicon pixels, silicon strips and straw tubes in a 2 T magnetic field. Its installation was completed in August 2008 and the detector took part in data-taking with single LHC beams and cosmic rays. The initial detector operation, hardware commissioning and in-situ calibrations are described. Tracking performance has been measured with 7.6 million cosmic-ray events, collected using a tracking trigger and reconstructed with modular pattern-recognition and fitting software. The intrinsic hit efficiency and tracking trigger efficiencies are close to 100%. Lorentz angle measurements for both electrons and holes, specific energy-loss calibration and transition radiation turn-on measurements have been performed. Different alignment techniques have been used to reconstruct the detector geometry. After the initial alignment, a transverse impact parameter resolution of 22.1 +/- 0.9 mu m and a relative momentum resolution sigma (p) /p=(4.83 +/- 0.16)x10(-4) GeV(-1)xp (T) have been measured for high momentum tracks.
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| 6. |
- Aad, G., et al.
(author)
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The ATLAS Simulation Infrastructure
- 2010
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In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:3, s. 823-874
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Journal article (peer-reviewed)abstract
- The simulation software for the ATLAS Experiment at the Large Hadron Collider is being used for large-scale production of events on the LHC Computing Grid. This simulation requires many components, from the generators that simulate particle collisions, through packages simulating the response of the various detectors and triggers. All of these components come together under the ATLAS simulation infrastructure. In this paper, that infrastructure is discussed, including that supporting the detector description, interfacing the event generation, and combining the GEANT4 simulation of the response of the individual detectors. Also described are the tools allowing the software validation, performance testing, and the validation of the simulated output against known physics processes.
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| 7. |
- Bengtsson, Peter, et al.
(author)
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Computer-Aided Planning of Production, Working and Residential Environments
- 1996
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In: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141 .- 1872-8219. ; 17:1, s. 59-68
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Journal article (peer-reviewed)abstract
- This paper discusses a computer-aided planning methodology and its applicability for planning of industrial production and working environments as well as for planning of residential and working environments for the differently abled. The methodology has been developed and evaluated in six case studies in mechanical industries and in six case studies related to adaptations for the differently abled. The results from the case studies indicate that computer-supported modelling and visualisation may serve as a common and efficient language facilitating communication about multifaceted environmental planning issues. The methodology is a cost-effective way of demonstrating layout ideas and testing dynamic activities like manufacturing and transportation. Corporate groups comprising people involved in, or affected by, development work seem to be a fruitful approach for cooperation, one which enhances learning and creativity. Such groups may be a proper forum for the dissemination of information, exchange of opinions, utilisation of both expert and lay experiences, and for public testing of current reality or future plans in such a way that mutual understanding between different professional categories is increased, hence promoting internal commitment.
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| 8. |
- Håkanson, Ulf, et al.
(author)
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Single InP/GaInP quantum dots studied by scanning tunneling microscopy and scanning tunneling microscopy induced luminescence
- 2002
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 80:3, s. 494-496
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Journal article (peer-reviewed)abstract
- We have studied the optical and structural properties of single, self-assembled InP quantum dots (QDs) overgrown with nominally 5 nm of GaInP, using an ultrahigh-vacuum scanning tunneling microscope (STM) operating at low temperatures. The STM is combined with an optical detection system, which allows us to detect the emission from individual quantum dots with high spatial resolution. We find that the InP QDs act as nucleation points for the GaInP overgrowth, where the strain induced by the overlayer give rise to a QD emission around 1.46 eV. (C) 2002 American Institute of Physics.
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| 9. |
- Johansson, Mikael, et al.
(author)
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Correlation between overgrowth morphology and optical properties of single self-assembled InP quantum dots
- 2003
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In: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 68:12
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Journal article (peer-reviewed)abstract
- We have studied the early stages of GaInP overgrowth on InP quantum dots (QD's) experimentally and theoretically. A direct correlation between the surface morphology and the optical properties of individual InP QD's is made using scanning tunneling microscopy (STM) and scanning tunneling luminescence. The geometric structure of the islands is further investigated using cross-sectional transmission electron microscopy (TEM). The overgrowth occurs in three stages; initially the InP QD's act as seeding points for the overgrowth, where the GaInP grows laterally from the side facets of the QD. The growth occurs preferentially in the [110] direction and elongated GaInP/InP islands are formed. As the overgrowth continues the islands increase laterally in size and GaInP also starts to grow between the islands, but not covering the top of the InP QD's. The growth of GaInP on top of the QD's commences once the islands have begun to coalesce. Using a model based on the STM and TEM results the electronic structures of the QD's have been calculated by eight-band k.p theory. The calculations are in good agreement with the experimental results. Our findings unravel the details of the strain induced energy shift of the QD luminescence previously reported [Pistol , Appl. Phys. Lett. 67, 1438 (1995)].
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| 10. |
- Johansson Wensman, Jonas, et al.
(author)
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Kennelhosta
- 2014
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In: Ulvehunden. - 2246-509X. ; 38, s. 10-11
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Journal article (pop. science, debate, etc.)
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