| 1. |
- Acharya, B. S., et al.
(författare)
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Introducing the CTA concept
- 2013
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Ingår i: Astroparticle physics. - : Elsevier BV. - 0927-6505 .- 1873-2852. ; 43, s. 3-18
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project. (C) 2013 Elsevier B.V. All rights reserved.
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| 2. |
- Actis, M., et al.
(författare)
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Design concepts for the Cherenkov Telescope Array CTA : an advanced facility for ground-based high-energy gamma-ray astronomy
- 2011
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Ingår i: Experimental astronomy. - : Springer. - 0922-6435 .- 1572-9508. ; 32:3, s. 193-316
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Tidskriftsartikel (refereegranskat)abstract
- Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.
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| 3. |
- Ackermann, M., et al.
(författare)
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Fermi-LAT Observations of the Gamma-Ray Burst GRB 130427A
- 2014
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 343:6166, s. 42-47
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Tidskriftsartikel (refereegranskat)abstract
- The observations of the exceptionally bright gamma-ray burst (GRB) 130427A by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope provide constraints on the nature of these unique astrophysical sources. GRB 130427A had the largest fluence, highest-energy photon (95 GeV), longest gamma-ray duration (20 hours), and one of the largest isotropic energy releases ever observed from a GRB. Temporal and spectral analyses of GRB 130427A challenge the widely accepted model that the nonthermal high-energy emission in the afterglow phase of GRBs is synchrotron emission radiated by electrons accelerated at an external shock.
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| 4. |
- Kariniemi, M., et al.
(författare)
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Effect of Blanket Properties on Web Tension in Offset Printing
- 2010
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Ingår i: Advances in Printing and Media Technology. - Montreal, Canada.
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Konferensbidrag (refereegranskat)abstract
- VTT and KCL together with several companies in the printing value chain have studied how to control web tension in different parts of a printing press. Extensive trials on printing presses, at pilot scale and at laboratory scale have yielded data for modeling work. Modeling was carried out with statistical methods and by finite element method (FEM). Results show the extent to which paper and printing blankets affect tension formation in a printing press. The main emphasis of this paper is on the effect different printing blanket types have on web tension.It was found that printing blankets have a clear effect on web tension. The degree of tension change is affected by the type of blanket, nip pressure, distances between the blankets, moisture, paper properties and the combination of blanket types in different printing units. Depending on their feeding properties and their effect on web tension, in general, the blankets can be distinguished as negative, neutral and positive. Also the blanket’s effect on web tension is influenced strongly by the type of adjacent blankets. The interactions of fountain solution, ink, nip, blanket and paper had also an effect on the tension formation. The paper experiences a very high rate of strain inside the printing nips, which can affect the paper’s response and therefore tension after the nips. Results suggest that tension cannot be solely predicted with the elastic paper properties measured by conventional methods.
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| 5. |
- Parola, S., et al.
(författare)
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Optoelectronic properties of p-i-n heterojunctions based on germanium nanocrystals
- 2013
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 114:3, s. 033510-
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the possibility of using physical vapour deposited Ge nanocrystals (NCs) in optoelectronic devices such as solar cells. We have prepared p-i-n heterojunctions based on p(+)-doped Si substrate/undoped Ge NCs/ZnO: Al layer stacks and their optoelectronic properties were characterised. Under light, the generation of photo-carriers from the Ge NCs themselves was demonstrated. The photovoltaic behaviour of the p-i-n structure was also highlighted, with a measured Voc of 224 mV compared to 580 mV in theory. The discrepancy between theory and experiment was discussed on the basis of TEM observations, optical and carrier generation measurements as well as modelling.
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| 6. |
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