| 11. |
- Åkesson, Torsten, et al.
(author)
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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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In: 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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Journal article (peer-reviewed)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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| 13. |
- Shin, C.-S., et al.
(author)
-
Epitaxial NaCl structure d-TaNx(001) : Electronic transport properties, elastic modulus, and hardness versus N/Ta ratio
- 2001
-
In: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 90:6, s. 2879-2885
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Journal article (peer-reviewed)abstract
- While metastable Bl-NaCl-structure d-TaNx. is presently used in a variety of hard coating, wear-resistant, and diffusion barrier applications, it is a complex material exhibiting a wide single-phase field, x?0.94-1.37, and little is known about its fundamental properties. Here, we report physical properties of epitaxial d-TaNx. layers grown as a function of x on MgO(00) by ultrahigh vacuum reactive magnetron sputter deposition. The room-temperature resistivity (? = 225 µO cm), hardness (H = 30.9 GPa), and elastic modulus (E = 455 GPa) of d-TaNx(001) are independent of x over the range 0.94-1.22. However, changes in the electronic structure associated with increasing x>1.22 lead to an increase in ? with a decrease in H and E. All d-TaNx(001) layers exhibit negative temperature coefficients of resistivity between 20 and 400 K due to weak carrier localization. d-TaNx is superconducting with the highest critical temperature, 8.45 K, obtained for layers with the lowest N/Ta ratio, x=0.94. Based upon the above results, combined with the fact that the relaxed lattice constant a0 shows only a very weak dependence on x, we propose that the wide phase field in d-TaNx is due primarily to antisite substitutions of Ta on N (and N on Ta) sites, rather than to cation and anion vacancies. To first order, antisite substitutions in TaNx are isoelectronic and hence have little effect on charge carrier density. At sufficiently high N/Ta ratios, however, simple electron-counting arguments are no longer valid since large deviations from stoichiometry alter the character of the band structure itself. © 2001 American Institute of Physics.
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