Commissioning and Performance of the ATLAS Liquid Argon Calorimeters

The ATLAS liquid argon (LAr) calorimeter system consists of an electromagnetic barrel calorimeter and two end-caps with electromagnetic, hadronic and forward calorimeters. The construction of the full calorimeter system is completed since mid-2004. The detector has been operated with LAr at nominal high voltage and fully equipped with readout electronics. Online software, monitoring tools and offline signal reconstruction have been developed for data collection and processing. Extensive tests with calibration pulses have been carried out, and the electronics calibration scheme for all 182468 channels has been exercised. Since Augst 2006, cosmic muon data have been collected together with the rest of the ATLAS detector system as part of the ATLAS commissioning program. The reconstructed LAr signals from energy deposited by cosmic rays are compared to the prediction derived from measured detector parameters and calibration pulses. The uniformity of the detector response within regions that have sufficient cosmic muons are examined. The expected performance of the LAr calorimeter for ATLAS physics, based on previous beam tests and Monte Carlo simulation, is also summarised.Comment: Parallel talk at ICHEP08, Philadelphia, USA, July 2008. 5 pages, LaTeX, 4 eps figures; v2: resubmitted article with updated style file provided by the ICHEP proceedings team. No other change

Vertex-Detector R&D for CLIC

A detector concept based on hybrid planar pixel-detector technology is under development for the CLIC vertex detector. It comprises fast, low-power and small-pitch readout ASICs implemented in 65 nm CMOS technology (CLICpix) coupled to ultra-thin sensors via low-mass interconnects. The power dissipation of the readout chips is reduced by means of power pulsing, allowing for a cooling system based on forced gas flow. In this paper the CLIC vertex-detector requirements are reviewed and the current status of R&D on sensors, readout and detector integration is presented.Comment: 12 pages, 7 figures. Talk presented at the 13th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD13), 7 - 10 October 2013, Siena, Ital

Probing Extra Dimensions with ATLAS

In the late nineties several authors suggested that the extra dimensions predicted by string theory might lead to observable effects at high energy colliders. The ATLAS experiment which will start taking data at the LHC in 2007 will be an excellent place to search for such effects. The sensitivity of ATLAS to signatures of Extra Dimensions will be presented.Comment: 4 pages, 1 figure, to appear in Proceedings of SUSY06, the 14th International Conference on Supersymmetry and the Unification of Fundamental Interactions, UC Irvine, California, 12-17 June 200

CLIC Background Studies and optimization of the innermost tracker elements

The harsh machine background at the Compact Linear Collider (CLIC) forms a strong constraint on the design of the innermost part of the tracker. For the CLIC Conceptual Design Report, the detector concepts developed for the International Linear Collider (ILC) were adapted to the CLIC environment. We present the new layout for the Vertex Detector and the Forward Tracking Disks of the CLIC detector concepts, as well as the background levels in these detectors. We also study the dependence of the background rates on technology parameters like thickness of the active layer and detection threshold.Comment: 7 pages, 5 figures, LCWS 201

Use of Recycling-Glass for Porcelain Production

High additives of grinded recycling-glass lowers the firing temperature of porcelain down to 1100°C. Α slip casting and a press mass were developed. Thereby the amount of glassy phase in the porcelain body rises. With thermal quenching methods it is possible to bring compressive stresses in the surface and so increase the strength of porcelain. The amount of stress in the two phase system mullite-glass was calculated by FEM methods. The strength was measured with a bending method. These stresses were compared with the experimental increase of strength of about 30 4 0 %. Because of the high amount of glassy phase in the vitreous silicate ceramics also chemical strengthening through ion-exchange is possible. Here, a strength increase of 80 % could be achieved

CLIC e+e- Linear Collider Studies - Input to the Snowmass process 2013

This paper addresses the issues in question for Energy Frontier Lepton and Gamma Colliders by the Frontier Capabilities group of the Snowmass 2013 process and is structured accordingly. It will be accompanied by a paper describing the Detector and Physics studies for the CLIC project currently in preparation for submission to the Energy Frontier group.Comment: Submitted to the Snowmass process 2013. arXiv admin note: substantial text overlap with arXiv:1208.140

Giving the International Court of Justice the Cold Shoulder: The Impact of Sanchez-Llamas v. Oregon on the United States International Relations

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Quality assurance of sintered refractories through nondestructive testing with microwaves

For quality assurance of refractories for the glass industry an early nondestructive testing is required. Α possibility for nondestructive testing, especially in the green product, is given by the transidon of microwaves, as this requires no coupling medium like water. In this work, some basic physical characteristics were measured which determine microwave absorption through refractories and flaw detection. For different refractories the dielectric constant, specific attenuation coefficient as well as dependence of the attenuation on the frequency were determined. It is shown that a high dielectric constant improves the detection of flaws. In order to improve flaw detection and resolution, lenses and frequency modulation were used successfully. Best results for the refractories investigated were achieved with a lens with a focal length of 86 mm. Measurements were then extended to other types of refractories, i.e. chromalumina, zirconmuUite and zirconsilica, as well as to unfired bricks. Here, especially one isostatic-pressed zirconsilica brick has shown the lowest specific attenuation coefficient due to low porosity and high dielectric constant. Furthermore, a test device for complete C-scans of large refractory samples was developed and tested successfully. Α number of refractories without or with natural and artificial flaws, respectively, were checked. Nondestructive testing with microwaves has now been sufficiently developed to be transferred to industrial use