MICROMEGAS chambers for hadronic calorimetry at a future linear collider

Prototypes of MICROMEGAS chambers, using bulk technology and analog readout, with 1x1cm2 readout segmentation have been built and tested. Measurements in Ar/iC4H10 (95/5) and Ar/CO2 (80/20) are reported. The dependency of the prototypes gas gain versus pressure, gas temperature and amplification gap thickness variations has been measured with an 55Fe source and a method for temperature and pressure correction of data is presented. A stack of four chambers has been tested in 200GeV/c and 7GeV/c muon and pion beams respectively. Measurements of response uniformity, detection efficiency and hit multiplicity are reported. A bulk MICROMEGAS prototype with embedded digital readout electronics has been assembled and tested. The chamber layout and first results are presented

Development of innovative micropattern gaseous detectors with resistive electrodes and first results of their applications

The paper summarizes our latest progress in the development of newly introduced micro pattern gaseous detectors with resistive electrodes. These resistive electrodes protect the detector and the front-end electronics in case of occasional discharges and thus make the detectors very robust and reliable in operation. As an example, we describe in greater detail a new recently developed GEM-like detector, fully spark-protected with electrodes made of resistive kapton. We discovered that all resistive layers used in these studies (including kapton), that are coated with photosensitive layers, such as CsI, can be used as efficient photo cathodes for detectors operating in a pulse counting mode. We describe the first applications of such detectors combined with CsI or SbCs photo cathodes for the detection of UV photons at room and cryogenic temperatures.Comment: Presented at the 11 Vienna Conference on Instrumentation, February, 200

R&D in ALICE: The CsI-based RICH high momentum particle identification detector

We report on the R&D studies performed on a CsI-based RICH detector with a liquid perfluorohexane radiator running pure methane at atmospheric pressure. The development, initiated by the CERN RD26 project in 1993, has been pursued in the framework of the ALICE/HMPID collaboration. A prototype of the detector under construction for ALICE is taking data since two years in the STAR experiment at RHIC

LOCALISATION BIDIMENSIONNELLE DES POSITIONS DES TRAJECTOIRES DE PARTICULES DANS DES CHAMBRES PROPORTIONNELLES AVEC UNE GRANDE RÉSOLUTION SPATIALE ET TEMPORELLE

En mesurant le centroïde des distributions de charges introduites sur des bandes de cathode perpendiculaires et parallèles aux fils d'anodes il est possible d'aboutir à une méthode de localisation présentant des avantages considérables. — Le temps de résolution, peut être réduit à 30 nanosecondes. — La mesure de la coordonnée le long des fils a une précision limitée simplement par la distribution physique des charges. La contribution de la méthode de lecture est inférieure à 7 microns. — La coordonnée perpendiculaire aux fils peut être plus précise que la séparation entre les fils même pour les trajectoires orthogonales au plan des chambres. — Les ambiguïtés relatives aux trajectoires multiples peuvent être levées dans la majorité des cas avec une seule chambre.— La mesure simultanée des coordonnées de nombreuses trajectoires est possible avec un pouvoir de séparation de l'ordre de 0,5 cm.By measuring the centroid of the charges induced on cathods of MWPC two dimensional localization can be obtained with advantageous properties. — Resolution time of 30 ns — The accuracy of the coordinate along the anode wires is limited only by the physical fluctuations in the centroid position. The read out contributes by 7 µm at most to the errors. — Interpolation between the anode wires is obtained over a wide angular range