| 1. |
- Alcorn, J, et al.
(författare)
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Basic instrumentation for Hall A at Jefferson Lab
- 2004
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 522:3, s. 294-346
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Tidskriftsartikel (refereegranskat)abstract
- The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electro-and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. The central components of Hall A are two identical high resolution spectrometers, which allow the vertical drift chambers in the focal plane to provide a momentum resolution of better than 2 x 10(-4). A variety of Cherenkov counters, scintillators and lead-glass calorimeters provide excellent particle identification. The facility has been operated successfully at a luminosity well in excess of 10(38) CM-2 s(-1). The research program is aimed at a variety of subjects, including nucleon structure functions, nucleon form factors and properties of the nuclear medium. (C) 2003 Elsevier B.V. All rights reserved.
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| 2. |
- Åkesson, Torsten, et al.
(författare)
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An X-ray scanner for wire chambers
- 2003
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 507:3, s. 622-635
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Tidskriftsartikel (refereegranskat)abstract
- The techniques to measure the position of sense wires and field wires, the gas gain and the gas flow rate inside wire chambers using a collimated and filtered X-ray beam are reported. Specific examples are given using barrel modules of the Transition Radiation Tracker of the ATLAS experiment. (C) 2003 Elsevier B.V. All rights reserved.
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| 3. |
- Åkesson, Torsten, et al.
(författare)
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ATLAS Transition Radiation Tracker test-beam results
- 2004
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 522:1-2, s. 50-55
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Konferensbidrag (refereegranskat)abstract
- Several prototypes of the Transition Radiation Tracker for the ATLAS experiment at the LHC have been built and tested at the CERN SPS accelerator. Results from detailed studies of the straw-tube hit registration efficiency and drift-time measurements and of the pion and electron spectra without and with radiators are presented.
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| 4. |
- Åkesson, Torsten, et al.
(författare)
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Status of design and construction of the Transition Radiation Tracker (TRT) for the ATLAS experiment at the LHC
- 2004
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 522:1-2, s. 131-145
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Tidskriftsartikel (refereegranskat)abstract
- The ATLAS Inner Detector consists of three sub-systems, the Pixel Detector at the innermost radius, the Semi-Conductor Tracker at intermediate radii, and the Transition Radiation Tracker (TRT) at the outermost radius in front of the electromagnetic calorimeter. The TRT provides a combination of continuous tracking with many projective measurements based on individual drift-tubes (or straws) and of electron identification based on radiator fibres or foils interleaved between the straws themselves. This paper describes the current status of design and construction of the various components of the TRT: the assembly of the barrel modules has recently been completed, that of the end-cap wheels is well underway, and the on-detector front-end electronics is in production. The detector modules and front-end electronics boards will be integrated together over the next year, the barrel and end-cap TRT parts will be assembled and tested with their SCT counterparts during 2005 and installation and commissioning in the ATLAS pit will take place at the end of 2005 and the beginning of 2006. (C) 2004 Elsevier B.V. All rights reserved.
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| 5. |
- Åkesson, Torsten, et al.
(författare)
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Operation of the ATLAS Transition Radiation Tracker under very high irradiation at the CERN LHC
- 2004
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 522:1-2, s. 25-32
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Konferensbidrag (refereegranskat)abstract
- The ATLAS Transition Radiation Tracker (TRT) performance depends critically on the choice of the active gas and on its properties. The most important operational aspects, which have led to the final choice of the active gas for the operation of the TRT at the LHC design luminosity, are presented. The TRT performance expected at these conditions is reviewed, including pile-up effects at high luminosity. (C) 2004 Elsevier B.V. All rights reserved.
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| 6. |
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| 7. |
- Edmonds, K. W., et al.
(författare)
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Magnetism of exposed and Co-capped Fe nanoparticles
- 2000
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Ingår i: Journal of Magnetism and Magnetic Materials. - 0304-8853 .- 1873-4766. ; 220:1, s. 25-30
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Tidskriftsartikel (refereegranskat)abstract
- The effect of capping a dilute assembly of nanoscale mass-selected Fe clusters with a Co thin film has been studied using X-ray magnetic circular dichroism (XMCD). The clusters, containing around 400 atoms, were deposited in situ from a gas-aggregation source onto highly oriented pyrolytic graphite. The exposed clusters possess magnetic moments that are enhanced compared to the bulk, by around 4% for m(spin) and around 75% for m(orb). In addition, a surface core level shifted component is observed in the L-3.2 XMCD spectrum. Upon adding the Co layer, the surface component disappears, m(orb) is decreased for the Fe clusters, and m(spin) increases. The exposed clusters are magnetically isotropic but a strong in-plans anisotropy is observed after depositing the Co overlayer. We attribute this to the shape of the Co islands in which the Fe clusters are embedded.
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| 8. |
- Edmonds, K. W., et al.
(författare)
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Size dependence of the magnetic moments of exposed nanoscale iron particles
- 2001
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Ingår i: Journal of Magnetism and Magnetic Materials. - 0304-8853 .- 1873-4766. ; 231:1, s. 113-119
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Tidskriftsartikel (refereegranskat)abstract
- The magnetic moments in exposed, mass-selected, nanoscale Fe clusters in the size range 1.89-2.20 nm (300-475 atoms), deposited onto graphic in situ have been measured by X-ray magnetic circular dichroism. The smallest clusters possess moments that are enhanced by around 4% for m(spin) and 80% for m(orb) and decrease towards the bulk value with increasing size. The larger clusters show an in-plane anisotropy that is consistent with the anisotropy in the orbital moment. The smallest clusters are, within experimental error, magnetically isotropic. The anisotropy constant in the 475-atom clusters is significantly higher than the bulk value.
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| 9. |
- Engelmark, O., et al.
(författare)
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Ecological effects and management aspects of an exotic tree species : the case of lodgepole pine in Sweden
- 2001
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Ingår i: Forest Ecology and Management. - 0378-1127 .- 1872-7042. ; 141:02-jan, s. 3-13
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Tidskriftsartikel (refereegranskat)abstract
- The North American tree Pinus contorta var, latifolia was experimentally introduced in Sweden already in the 1920s, and has been used in Swedish forestry on a large scale since the 1970s. These plantations now cover 565,000 ha, mainly in the northern area. In this paper we summarize and discuss existing ecological knowledge of this species introduction. With regard to longterm sustainability we suggest management means to minimize harmful effects of the introduction on ecosystems. These include aspects of self dispersal, pests, ecosystem and landscape structures, and also ecological processes and biodiversity. We also focus on observed and possible interactions in the ecosystems. As Pinus contorta seeds are disseminated and trees regenerated outside initial plantations, this may have future bearings on biodiversity. We suggest a strategy which takes account of the uncertainty in predicting future ecological effects. The strategy includes areal restrictions and zones without Pinus contorta, but also to set up a monitoring program. Observations of adverse effects from the plantations would then give the possibility to adjust P. contorta management.
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| 10. |
- Grover, A, et al.
(författare)
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A novel tau mutation in exon 9 (1260V) causes a four-repeat tauopathy
- 2003
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Ingår i: Experimental Neurology. - 0014-4886. ; 184:1, s. 131-140
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Tidskriftsartikel (refereegranskat)abstract
- A novel mutation in exon 9 of tau, I260V, is associated with a clinical syndrome consistent with frontotemporal dementia with extensive tau pathology; however, neurofibrillary tangles and Pick bodies are absent. Significantly, Sarkosyl- insoluble tau extracted from affected brain tissue consisted almost exclusively of four-repeat isoforms. Consistent with these findings, in vitro biochemical assays demonstrated that the I260V mutation causes a selective increase in tau aggregation and a decrease in tau-induced microtubule assembly with four-repeat isoforms only. The contrasting pathology and biochemical effects of this mutation suggest a different disease mechanism from the other exon 9 mutations and demonstrates the critical role for the first microtubule-binding domain in tau-promoted microtubule assembly and the pathogenic aggregation of tau.
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