| 1. |
- Abate, E., et al.
(author)
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Combined performance tests before installation of the ATLAS Semiconductor and Transition Radiation Tracking Detectors
- 2008
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In: Journal of Instrumentation. - 1748-0221. ; 3
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Journal article (peer-reviewed)abstract
- The ATLAS (A Toroidal LHC ApparatuS) Inner Detector provides charged particle tracking in the centre of the ATLAS experiment at the Large Hadron Collider (LHC). The Inner Detector consists of three subdetectors: the Pixel Detector, the Semiconductor Tracker (SCT), and the Transition Radiation Tracker (TRT). This paper summarizes the tests that were carried out at the final stage of SCT+TRT integration prior to their installation in ATLAS. The combined operation and performance of the SCT and TRT barrel and endcap detectors was investigated through a series of noise tests, and by recording the tracks of cosmic rays. This was a crucial test of hardware and software of the combined tracker detector systems. The results of noise and cross-talk tests on the SCT and TRT in their final assembled configuration, using final readout and supply hardware and software, are reported. The reconstruction and analysis of the recorded cosmic tracks allowed testing of the offline analysis chain and verification of basic tracker performance parameters, such as efficiency and spatial resolution, in combined operation before installation.
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| 2. |
- Abdesselam, A., et al.
(author)
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Engineering for the ATLAS SemiConductor Tracker (SCT) end-cap
- 2008
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In: Journal of Instrumentation. - 1748-0221. ; 3
-
Journal article (peer-reviewed)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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| 3. |
- Abdesselam, A., et al.
(author)
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The ATLAS semiconductor tracker end-cap module
- 2007
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In: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 575:3, s. 353-389
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Journal article (peer-reviewed)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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| 4. |
- Abdesselam, A., et al.
(author)
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The barrel modules of the ATLAS semiconductor tracker
- 2006
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In: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 568:2, s. 642-671
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Journal article (peer-reviewed)abstract
- This paper describes the silicon microstrip modules in the barrel section of the SemiConductor Tracker (SCT) of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The module requirements, components and assembly techniques are given, as well as first results of the module performance on the fully assembled barrels that make up the detector being installed in the ATLAS experiment.
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| 5. |
- Wilson, J. A., et al.
(author)
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The optical links of the ATLAS SemiConductor tracker
- 2007
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In: Journal of Instrumentation. - 1748-0221. ; 2, s. 1-28
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Journal article (peer-reviewed)abstract
- Optical links are used for the readout of the 4088 silicon microstrip modules that make up the SemiConductor Tracker of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The optical link requirements are reviewed, with particular emphasis on the very demanding environment at the LHC. The on-detector components have to operate in high radiation levels for 10 years, with no maintenance, and there are very strict requirements on power consumption, material and space. A novel concept for the packaging of the on-detector optoelectronics has been developed to meet these requirements. The system architecture, including its redundancy features, is explained and the critical on-detector components are described. The results of the extensive Quality Assurance performed during all steps of the assembly are discussed.
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| 6. |
- Johansson, Patrik, et al.
(author)
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Puumala hantavirus genetic variability in an endemic region (Northern Sweden)
- 2008
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In: Infection, Genetics and Evolution. - : Elsevier BV. - 1567-1348 .- 1567-7257. ; 8:3, s. 286-296
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Journal article (peer-reviewed)abstract
- Puumala hantavirus (PUUV), naturally harboured and shed by bank voles (Myodes [Clethrionomys] glareolus), is the etiological agent to nephropathia epidemica (NE), a mild haemorrhagic fever with renal syndrome. Both host and virus are found throughout much of the European continent and in northern Sweden NE is the second most prevalent serious febrile viral infection after influenza. The reliability of diagnostics by PCR depends on genetic variability for the detection of viral nucleic acids in unknown samples. In the present study we evaluated the genetic variability of PUUV isolated from bank voles in an area of northern Sweden highly endemic for NE. Genetic variability among bank voles was also investigated to evaluate co-evolutionary patterns. We found that the viral sequence appeared stable across the 80 km study region, with the exception of the southernmost sampling site, which differed from its nearest neighbour by 7%, despite a geographical separation of only 10 km. The southernmost sampling site demonstrated a higher degree of genetic similarity to PUUV previously isolated 100 km south thereof; two locations appear to constitute a separate PUUV phylogenetic branch. In contrast to the viral genome, no phylogenetic variance was observed in the bank vole mtDNA in this study. Previous studies have shown that as a result of terrestrial mammals' postglacial re-colonization routes, bank voles and associated PUUV of a southern and a northern lineage established a dichotomous contact zone across the Scandinavian peninsula approximately 100-150km south of the present study sites. Our observations reveal evolutionary divergence of PUUV that has led to dissimilarities within the restricted geographical scale of the northern host re-colonization route as well. These results suggest either a static situation in which PUUV strains are regionally well adapted, or an ongoing process in which strains of PUUV circulate on a geographical scale not yet reliably described. (c) 2008 Elsevier B.V. All rights reserved.
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| 7. |
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| 8. |
- Liu, Johan, 1960, et al.
(author)
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Thermal management technologies for electronics based on multiwalled carbon nanotube bundles: As power consumption increases, so does the need for more efficient heat removal technologies
- 2009
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In: IEEE Nanotechnology Magazine. - 1932-4510. ; 3:1, s. 17-19
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Journal article (peer-reviewed)abstract
- As electronic circuits grow denser and their power consumption per unit area is increasing, new, more efficient technologies for heat removal are necessary. Heat fluxes from the IC on the order of 100 W/cm 2 (1 million W/m 2) are not rare. A heat transfer coefficient (including a possible area enlarging factor) of 20,000 W/m 2K is needed to accommodate a heat flux of 100 W/ cm 2 at a temperature difference of 50 K. The application of nanotechnologies is considered as a revolutionary approach to meet the tougher requirements for thermal management of electronics. There are two possible approaches to improve the cooling of microelectronics packages. The first is to improve the thermal conductivity of the packaging material and package geometry so that the thermal gradient within it becomes smaller. The second is to improve the heat removal, i.e., increase the effect of the convective heat transfer, from the surface or from the inside of the package.
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| 9. |
- Teng, L. D., et al.
(author)
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Thermodynamic investigations of the Mn-Ni-C-N quarternary alloys by solid-state galvanic cell technique
- 2005
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In: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 388:2, s. 250-257
-
Journal article (peer-reviewed)abstract
- In view of the important applications of carbides and nitrides of transition metals in the hard materials industries, the thermodynamic activities of manganese in Mn-Ni-C-N alloys have been studied by solid-state galvanic cell technique with CaF2 as the solid electrolyte. The phase compositions and microstructure of various alloys have been analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Nitrogen was introduced into the alloy by equilibrating with N-2 gas. It was established during the experiments that the solubility of nitrogen in the alloys was affected by the carbon content. A (Mn,Ni)(4)(N,C) nitride was formed during the nitriding procedure in the alloys. The electromotive force (EMF) measurements were carried out in the temperature range 940-1127 K in order to determine the activities of Mn in the alloys. The activities of manganese were calculated and compared with those of the corresponding Mn-Ni-C ternary alloys.
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| 10. |
- Wang, Teng, 1983, et al.
(author)
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Development and Characterization of Microcoolers using Carbon Nanotubes
- 2006
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In: Proceedings of the 1st IEEE CPMT Electronics Systemintegration Technology Conference (ESTC2006). - 1424405521 ; , s. 881-885
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Conference paper (peer-reviewed)abstract
- The continuously increasing integration and packaging density of microelectronic systems requires high-performance cooling technologies, among which the microchannel cooler is considered as a good approach. This work aims to develop a microchannel cooler with vertically aligned carbon nanotubes as the fins. Carbon nanotubes have unusually high thermal conductivity along with the possibility of small-scale formatting and wafer-level integration with chips, thus they provide a promising solution to implement microchannel coolers. By using photolithography, chemical vapor deposition, and adhesive bonding techniques, microcoolers containing carbon nanotube fins of different sizes and spacings are fabricated and then tested. They are also compared to a cooler with common silicon fins, as well as one with no fins. The experimental results reveal good heat removal capability of microcoolers using carbon nanotubes. The measurement result of the CNT cooler is about 10-15% better than the silicon cooler.
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| 11. |
- Wang, Teng, 1983, et al.
(author)
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Development of Carbon Nanotube Bumps for Ultra Fine Pitch Flip Chip Interconnection
- 2006
-
In: 1st Electronics Systemintegration Technology Conference; Dresden, Saxony; Germany; 5 September 2006 through 7 September 2006. - 9781424405527 ; 2, s. 892-895
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Conference paper (peer-reviewed)abstract
- Since 1991, carbon nanotubes have been considered for successful applications in various fields due to their unique properties. In the present work, carbon nanotubes are applied in integrated circuit packaging, as the bump interconnection for flip chip. The reason for choosing carbon nanotubes as the bump material is their special electrical, mechanical and thermal properties, which may promote both the performance and reliability of the flip chip packaging. Moreover, carbon nanotubes can be formed according to a precisely predefined small-scale pattern, which makes extremely high density interconnection possible. Vertically aligned carbon nanotubes are grown on silicon in the form of square arrays of different sizes, heights and pitches. Attempts to use thermal compression and anisotropic conductive adhesive to bond chips carrying carbon nanotube bumps with ceramic substrates are also executed. Mechanical testing is performed afterward to determine the strength of the bonding interfaces. The strength of the bonding by thermal compression is very weak, in the range from 1.9 to 7.0 g/mm2. The bonding by anisotropic conductive adhesive is much stronger, indicating a possible approach to bond chips carrying carbon nanotube bumps.
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| 12. |
- Wang, Teng, 1983, et al.
(author)
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Low temperature transfer and formation of carbon nanotube arrays by imprinted conductive adhesive
- 2007
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 91:9
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Journal article (peer-reviewed)abstract
- This letter demonstrates the transfer and formation of aligned carbon nanotube (CNT) arrays at low temperature by imprinted conductive adhesive. A thermoplastic isotropic conductive adhesive is patterned by an imprint and heat transfer process. The CNTs grown by thermal chemical vapor deposition are then transferred to another substrate by the conductive adhesive, forming predefined patterns. The current-voltage response of the transferred CNT bundles verifies that good electrical connection has been established. This process can enable the integration of CNTs into various temperature-sensitive processeses and materials.
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| 13. |
- Wang, Teng, 1983, et al.
(author)
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Through silicon vias filled with planarized carbon nanotube bundles
- 2009
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In: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 20:48
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Journal article (peer-reviewed)abstract
- The feasibility of using carbon nanotube (CNT) bundles as the fillers of through silicon vias (TSVs) has been demonstrated. CNT bundles are synthesized directly inside TSVs by thermal chemical vapor deposition (TCVD). The growth of CNTs in vias is found to be highly dependent on the geometric dimensions and arrangement patterns of the vias at atmospheric pressure. The CNT-Si structure is planarized by a combined lapping and polishing process to achieve both a high removal rate and a fine surface finish. Electrical tests of the CNT TSVs have been performed and their electrical resistance was found to be in the few hundred ohms range. The reasons for the high electrical resistance have been discussed and possible methods to decrease the electrical resistance have been proposed.
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