| 1. |
- Collins, P., et al.
(författare)
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The LHCb VELO upgrade
- 2011
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 636, s. S185-S193
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Tidskriftsartikel (refereegranskat)abstract
- The LHCb experiment at the LHC plans to massively increase its data taking capabilities by running at a higher luminosity with a fully upgraded detector around 2016. This scheme is independent of (but compatible with) the plans for the SLHC upgrades. The silicon detector will be upgraded to provide a 40 MHz readout and to be able to cope with the increased radiation environment. This paper describes the options currently under consideration. A highlight of the R&D so far undertaken is a beam test during summer 2009 using the Timepix chip to track charged particles. Preliminary results are presented, including a measurement of the resolution achieved by the 55 mu m pitch pixel array of better than 9.5 mu m for perpendicular tracks and 55 mu m for angled tracks.
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| 2. |
- Aghion, S., et al.
(författare)
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A moiré deflectometer for antimatter
- 2014
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- The precise measurement of forces is one way to obtain deep insight into the fundamental interactions present in nature. In the context of neutral antimatter, the gravitational interaction is of high interest, potentially revealing new forces that violate the weak equivalence principle. Here we report on a successful extension of a tool from atom optics—the moiré deflectometer—for a measurement of the acceleration of slow antiprotons. The setup consists of two identical transmission gratings and a spatially resolving emulsion detector for antiproton annihilations. Absolute referencing of the observed antimatter pattern with a photon pattern experiencing no deflection allows the direct inference of forces present. The concept is also straightforwardly applicable to antihydrogen measurements as pursued by the AEgIS collaboration. The combination of these very different techniques from high energy and atomic physics opens a very promising route to the direct detection of the gravitational acceleration of neutral antimatter.
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| 3. |
- Ariga, T., et al.
(författare)
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Measuring GBAR with emulsion detector
- 2014
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Ingår i: International Journal of Modern Physics, Conference Series. - : World Scientific. - 2010-1945. ; 30
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Huse, M., et al.
(författare)
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Neutron diffraction study of the monoclinic to tetragonal structural transition in LaNbO4 and its relation to proton mobility
- 2012
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Ingår i: Journal of Solid State Chemistry. - : Elsevier BV. - 0022-4596 .- 1095-726X. ; 187, s. 27-34
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Tidskriftsartikel (refereegranskat)abstract
- The fergusonite-scheelite structural transition of LaNbO4 was characterized by high-intensity variable temperature neutron powder diffraction in an effort to link structural changes to proton transport in the low temperature monoclinic and high temperature tetragonal polymorphs. The pronounced decrease in enthalpy of proton mobility with increasing temperature in monoclinic LaNbO4, identified by Field et al. [1], was found to coincide with the decrease in a key inter-tetrahedral oxygen separation. At temperatures above the transition, this oxygen to oxygen distance remains constant, behavior that is consistent with the invariant nature of the calculated enthalpy of mobility for the tetragonal phase. This oxygen separation is therefore proposed as the key structural parameter determining the success rate of proton transfer and ultimately the proton diffusion in LaNbO4. Infrared measurements performed on acceptor-doped LaNbO4 show an absorption in the region 2500 to 3700 cm(-1) attributed to the O-H stretching motion influenced by hydrogen bonding.
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