SEARCH · Searcharxiv
Search indexed arXiv papers on artificial intelligence, large language models, computer vision and robotics. Read source abstracts and follow links to arXiv.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
A new radiation sensor derived from plasma panel display technology is introduced. It has the capability to detect ionizing and non-ionizing radiation over a wide energy range and the potential for use in many applications. The principle of operation is described and some early results presented.
We report on the development of an GRPCs (Glass Resistive Plate chambers) Semi- Digital hadron calorimeter for the future International Linear Collider (ILC).Two types of GRPCs (small and 1m2) were tested in PS beam at CERN. Detector performances are presented here in terms of efficiency, pad multiplicity, homogeneity and stability in time.
The two calorimeters CASTOR and ZDCs enhance the hermeticity of the CMS detector at the LHC by extending the rapidity coverage in the forward region. After having described these detectors, their forward physics capabilities are presented. These latters include the study of parton shower, multiple parton interactions, diffraction and ultra high energy cosmic rays models. The processes to be measured to constrain these topics are multi-jet events with a forward jet, central-forward activity correlation, rapidity gaps and forward neutron production.
The ATLAS experiment is one of two large general-purpose particle detectors at the Large Hadron Collider (LHC) at the CERN laboratory in Geneva, Switzerland. ATLAS has been collecting data from the collisions of protons since December 2009, in order to investigate the conditions that existed during the early Universe and the origins of mass, and other topics in fundamental particle physics. The innermost layers of the ATLAS detector will be exposed to the most radiation over the first few years of operation at the LHC. In particular, the layer closest to the beam pipe, the B-layer, will degrade over time due to the added radiation. To compensate for its degradation, it will be replaced with an Insertable B-Layer (IBL) around 2016. The design of and R&D for the IBL is ongoing, as the hope is to use the most current technologies in the building of this new sub-detector layer. One topic of interest is the use of more thermally conductive glues in the construction of the IBL, in order to facilitate in the dissipation of heat from the detector. In this paper the measurement and use of highly thermally conductive glues, in particular those that are diamond-loaded, will be discussed. The modified transient plane source technique for thermal conductivity is applied in characterizing the glues across a wide temperature range.
In this paper we present the design, modeling, and experimental testing of surface electrode ion traps fabricated in a heterostructure configuration comprising a silicon substrate, silicon dioxide insulators, and aluminum electrodes. This linear trap has a geometry with symmetric RF leads, two interior DC electrodes, and 40 individual lateral DC electrodes. Plasma enhanced chemical vapor deposition (PECVD) was used to grow silicon dioxide pillars to electrically separate overhung aluminum electrodes from an aluminum ground plane. In addition to fabrication, we report techniques for modeling the control voltage solutions and the successful demonstration of trapping and shuttling ions in two identically constructed traps.
In this script handbook, we collect the basic (and partially upgraded) PHP scripts used for building the AMIDAS website (http://pisrv0.pit.physik.uni-tuebingen.de/darkmatter/amidas/), an online interactive simulation/data analysis system for direct Dark Matter detection experiments and phenomenology. In this (1.73205) version, we add more materials and improve the scripts for offering a more convenient, comfortable and user-friendly environment on interactive scientific computing websites. Some basic, often used commands of (X)HTML, CSS, JavaScript, HTML DOM, and PHP are also given in Appendix. Online demonstrations and downloadable template scripts are given on http://www.tir.tw/iswb/ss2012/templates.php.
For the first time, we have measured the optical noise equivalent power (NEP) in titanium (Ti) superconducting hot-electron nanobolometers (nano-HEBs). The bolometers were 2μmx1μmx20nm and 1μmx1μmx20nm planar antenna-coupled devices. The measurements were done at λ = 460 μm using a cryogenic black body radiation source delivering optical power from a fraction of a femtowatt to a few 100s of femtowatts. A record low NEP = 3x10^{-19} W/Hz^{1/2} at 50 mK has been achieved. This sensitivity meets the requirements for SAFARI instrument on the SPICA telescope. The ways for further improvement of the nano-HEB detector sensitivity are discussed.
The performance of the three-level ATLAS muon trigger as evaluated by using LHC data is presented. Events have been selected by using only the hardware-based Level-1 trigger in order to commission and to subsequently enable the (software-based) selections of the High Level Trigger. Studies aiming at selecting prompt muons from J/ψ and at reducing non prompt muon contamination have been performed. A brief overview on how the muon triggers evolve with increasing luminosity is given.
The Inner Tracker of the LHCb experiment is a silicon microstrip detector consisting of 336 detector modules with either one or two sensors. The module production is now underway and we present here the setup employed for module testing during the production. The setup is based on the same electronics that will be used in the final experiment. We perform burn-in and ageing tests with the help of a custom made Temperature Cycling Box controlled with LabVIEW under Windows. The DAQ is done in another PC running Linux. Here we integrate the different C/C++ libraries used to communicate to the LHCb Time and Fast Control system,Experiment Control System and Data Acquisition.
We describe the laboratory complex for the calibration of photometers that are used in weather service to measure the water vapor content in the Earth atmosphere. The complex was built up in Pulkovo Observatory and developed within the framework of collaboration between Pulkovo Observatory and Lindenberg Meteorological Observatory (Meteorologisches Observatorium Lindenberg - Richard-Aßmann-Observatorium, Lindenberg, Germany). It is used to obtain calibration dependences for individual devices, and also to develop and compare various methods of construction of calibration dependences. These techniques are based on direct calibration of the photometers, on the use of spectral laboratory transmission functions for water vapor, on calculation methods using spectroscopical databases for individual lines. We hope that when the parameters of the equipment are taken into account in detail and new results for the absorptive power of water vapor are used, the accuracy of determination of the water vapor content in the atmosphere of 1-2% may be attained.
We report on the 3-dimensional imaging of biological cells including living neurons by a recently developed fibered interferometric Scanning Optical Microscope. The topography and surface structure of mouse fibroblasts and hippocampal neurons are clearly revealed. This straightforward technique allows fast, high resolution observation of samples in liquids without lengthy alignment procedures or costly components.
We retrieved the total content of the atmospheric water vapor (or Integrated Water Vapor, IWV) from extensive sets of photometric data obtained since 1995 at Lindenberg Meteorological Observatory with star and sun photometers. Different methods of determination of the empirical parameters that are necessary for the retrieval are discussed. The instruments were independently calibrated using laboratory measurements made at Pulkovo Observatory with the VKM-100 multi-pass vacuum cell. The empirical parameters were also calculated by the simulation of the atmospheric absorption by water vapor, using the MODRAN-4 program package for different model atmospheres. The results are compared to those presented in the literature, obtained with different instruments and methods of the retrieval. The reliability of the empirical parameters, used for the power approximation that links the water vapor content with the observed absorption, is analyzed. Currently, the total (from measurements, calibration, and calculations) errors yield the standard uncertainty of about 10% in the total column water vapor. We discuss the possibilities for improving the accuracy of calibration to ~1% as indispensable condition in order to make it possible to use data obtained by optical photometry as an independent reference for other methods (GPS, MW-radiometers, lidar, etc).
Two finely segmented and very compact calorimeters are foreseen for the instrumentation of the very forward region of the ILC and the CLIC detectors; a luminometer to measure the rate of low angle Bhabha scattering events with a precision better than $10^{-3}$ and, at lower polar angles, a detector for fast luminosity estimate. Both devices will improve the hermeticity of the detector in searches for new particles. Due to the expected high occupancy, fast front-end electronics is needed. The calorimeter closest to the beampipe will be hit by a large amount of beamstrahlung remnants, so that radiation hard sensors are required. Results on the performance of the sensor and readout electronics prototypes are summarized.
The EDELWEISS-II experiment uses cryogenic heat-and-ionization detectors in order to detect the rare interactions from possible WIMP dark matter particles on Germanium nuclei. Recently, new-generation detectors with an interleaved electrode geometry were developped and validated, enabling an outstanding rejection of gamma-rays and surface interactions. We present here preliminary results of a one-year WIMP search carried out with ten of such detectors in the Laboratoire Souterrain de Modane. A sensitivity to the spin-independent WIMP-nucleon cross-section of 5 \times 10-8 pb was achieved using a 322 kg
The CALICE collaboration is developing calorimeters for a future linear collider, and has collected a large amount of physics data during test beam efforts. For the analysis of these data, standard software available for linear collider detector studies is applied. This software provides reconstruction of raw data, simulation, digitization and data management, which is based on grid tools. The data format for analysis is compatible with the general linear collider software. Moreover, existing frameworks such as Marlin are employed for the CALICE software needs. The structure and features of the software framework are reported here as well as results from the application of this software to test beam data.
Osteoporosis is a well recognized problem affecting millions of individuals worldwide. Consequently, the need to effectively, efficiently, and affordably diagnose and identify those at risk is essential; moreover, site-specific assessment of bone quality is necessary, not only in the process of risk assessment, but may also be desirable for other applications. The present study evaluated a new one-dimensional granular crystal sensor, composed of a tightly packed chain of beads under Hertzian contact interaction, representing the most suitable fundamental component for solitary wave generation and propagation. First, the sensitivity of the novel sensor was tested using densities of rigid polyurethane foam, representing clinical bone quality ranging from healthy, to severely osteoporotic. Once the relationship between the signal response and known densities was established, the sensor was used to measure several sites located in the proximal femur of ten human cadaveric specimens. The accuracy of the model was then further investigated, using measurements of bone quality from the same cadaveric specimens, independently, using DEXA. The results indicate not only that the novel technique is capable of detecting differences in bone quality, but that the ability to measure site-specific properties without exposure to radiation, has the potential to be further developed for clinical applications.
In this thesis we investigate high throughput computational methods for processing large quantities of data collected from synchrotrons and their application to spectral analysis of powder diffraction data. We also present the main product of this PhD programme, specifically a software called 'EasyDD' developed by the author. This software was created to meet the increasing demand on data processing and analysis capabilities as required by modern detectors which produce huge quantities of data. Modern detectors coupled with the high intensity X-ray sources available at synchrotrons have led to the situation where datasets can be collected in ever shorter time scales and in ever larger numbers. Such large volumes of datasets pose a data processing bottleneck which augments with current and future instrument development. EasyDD has achieved its objectives and made significant contributions to scientific research. It can also be used as a model for more mature attempts in the future. EasyDD is currently in use by a number of researchers in a number of academic and research institutions to process high-energy diffraction data. These include data collected by different techniques such as Energy Dispersive Diffraction, Angle Dispersive Diffraction and Computer Aided Tomography. EasyDD has already been used in a number of published studies, and is currently in use by the High Energy X-Ray Imaging Technology project. The software was also used by the author to process and analyse datasets collected from synchrotron radiation facilities. In this regard, the thesis presents novel scientific research involving the use of EasyDD to handle large diffraction datasets in the study of alumina-supported metal oxide catalyst bodies. These data were collected using Tomographic Energy Dispersive Diffraction Imaging and Computer Aided Tomography techniques.
The LHC machine at CERN finished its first year of pp collisions at a center of mass energy of 7 TeV. While the commissioning to exploit its full potential is still ongoing, there are plans to upgrade its components to reach instantaneous luminosities beyond the initial design value after 2016. A corresponding upgrade of the innermost part of the CMS detector, the pixel detector, is needed. A full replacement of the pixel detector is planned in 2016. It will not only address limitations of the present system at higher data rates, but will aggressively lower the amount of material inside the fiducial tracking volume which will lead to better tracking and b-tagging performance. This article gives an overview of the project and illuminates the motivations and expected improvements in the detector performance.