Cosmic ray velocity and electric charge measurements with the AMS/RICH detector: prototype results

The Alpha Magnetic Spectrometer (AMS) to be installed on the International Space Station (ISS) will measure charged cosmic ray spectra of elements up to iron, in the rigidity range from 1 GV to 1 TV, for at least three years. AMS is a large angular spectrometer composed of different subdetectors, including a proximity focusing Ring Imaging CHerenkov (RICH) detector. This will be equipped with a mixed radiator made of aerogel and sodium fluoride (NaF), a lateral conical mirror and a detection plane made of 680 photomultipliers coupled to light guides. The RICH detector allows measurements of particle's electric charge up to iron, and particle's velocity. Two possible methods for reconstructing the Cherenkov angle and the electric charge with the RICH will be discussed. A RICH prototype consisting of a detection matrix with 96 photomultipliers, a segment of a conical mirror and samples of the radiator materials was built and its performance was evaluated using ion beam data. Results from the last test beam performed with ion fragments resulting from the collision of a 158 GeV/c/nucleon primary beam of indium ions (CERN SPS) on a lead target are reported. The large amount of collected data allowed to test and characterize different aerogel samples and the NaF radiator. In addition, the reflectivity of the mirror was evaluated. The data analysis confirms the design goals.Comment: 5 pages. Contribution to the 20th European Cosmic Ray Symposium in Lisbon, Portugal. September 5th-8th 2006. Presenter: Luisa Arrud

Systematic study of the response and calibration of the monitored drift tubes of the ATLAS muon spectrometer

The purpose of the work presented here is the study of the performance of the drift tubes of the ATLAS muon spectrometer. In particular, the analysis is focused on the development and optimization of the calibration tecnique, the study of the systematics involved and of the impact on the spatial resolution. That is the subject of the chapters from four to seven. It follows an analysis aimed the check for any evidence of degradation in the MDT preformance as a consequence of the extended exposure of the detector to the large particle flux during the accelerator operation. The first two chapters are dedicated to the description of the research program, the main characteristics of the experimental apparatus and the physical motivatons which have driven both the accelerator and the detector design with emphasis in the ATLAS Muon Spectrometer. The third chapter reviews the principles of operation of the drift tubes motivating the choice of the operating parameters of the ATLAS MDTs and the problematics related to the signal extraction. An overview of the experimental setups, the software tools and the analysis tecniques used can be found in chapter four

A brief network analysis of Artificial Intelligence publication

In this paper, we present an illustration to the history of Artificial Intelligence(AI) with a statistical analysis of publish since 1940. We collected and mined through the IEEE publish data base to analysis the geological and chronological variance of the activeness of research in AI. The connections between different institutes are showed. The result shows that the leading community of AI research are mainly in the USA, China, the Europe and Japan. The key institutes, authors and the research hotspots are revealed. It is found that the research institutes in the fields like Data Mining, Computer Vision, Pattern Recognition and some other fields of Machine Learning are quite consistent, implying a strong interaction between the community of each field. It is also showed that the research of Electronic Engineering and Industrial or Commercial applications are very active in California. Japan is also publishing a lot of papers in robotics. Due to the limitation of data source, the result might be overly influenced by the number of published articles, which is to our best improved by applying network keynode analysis on the research community instead of merely count the number of publish.Comment: 18 pages, 7 figure