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We compared the detection characteristics of a pixel area X-ray detector, Medipix-2, with those of a CCD-based X-ray detector. The goal was to challenge the overall imaging performance of the emerging pixel area detection technique against that of a well-known detection device, in view of applications on synchrotron beamlines. A CCD-based detector was chosen as the reference because of the intensive and widespread use of CCD systems on beamlines. In order to establish the comparison on an absolute side-by-side basis we built an optimized CCD-based system with the same input pixel size as Medipix-2 and we characterized both systems in identical conditions. We present the results obtained, in particular the frequency-dependent noise, spatial response and DQE. We also report on various test experiments with Medipix-2 in X-ray scattering and X-ray imaging using a synchrotron source. [ABSTRACT FROM AUTHOR]

LHCb is one of the experiments at the Large Hadron Collider at CERN. It aims to make precision measurements of CP violation in the B-meson decays. The detector simulation of LHCb was developed using the GEANT4 software toolkit interfaced to the LHCb software framework named GAUDI. This is now being used for a large production run of 210 million events. An important feature of the LHCb experiment is the use of Ring Imaging Cherenkov Counters (RICH) for particle identification. The Cherenkov photons created in this detector are focused onto an array of photodetectors made of Hybrid Photon Detectors. A brief overview of the GEANT4 based LHCb simulation program named GAUSS will be given with the main emphasis on RICH simulation and its verification. [ABSTRACT FROM AUTHOR]

The paper presents the design and first test results of the high-speed Beam Conditions Monitor (BCM) for the ATLAS Experiment at the Large-Hadron Collider (LHC). The goal of the BCM is to monitor instantaneous rates of collision and background and detect signs of beam instabilities. The detector is based on polycrystalline Chemical-Vapor-Deposition (pCVD) diamond as active sensor material. We have chosen this detector material for its proven radiation hardness and fast signal properties. For the readout of the diamonds we developed front-end readout electronics based on high-bandwidth RF amplifiers. The signal response of the amplifier has been optimized for the ionization current signal of pCVD diamond in order to achieve a signal rise time of ≤1 ns and pulsewidth of less than 3 ns. We present test results which were obtained on prototype assemblies in source tests and testbeam. The obtained results demonstrate the feasibility of such a detector system for the ATLAS BCM. The tests yield BCM signals with a mean rise time of 900 ps and a FWHM pulsewidth of 2.1 ns after 16 m of required transmission cable. The recorded signal amplitude distribution yields an most probable signal-to-noise ratio of 8.6:1 for single minimum-ionizing particles (MIP). [ABSTRACT FROM AUTHOR]