20 research outputs found

    POMIAR CZASU MARTWEGO METODĄ DWÓCH ŹRÓDEŁ – OPTYMIZACJA PODZIAŁU CZASU POMIARU

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    The article presents the analysis of the dead time measurement using two sources for a non-paralyzable detector. It determined the optimum division of count rate measurement time between both source measurement and a single source one. Results of the work can be used to optimize dead time measurement for systems which count photons or particles.W artykule zaprezentowano analizę pomiaru czasu martwego detektora nieparaliżowalnego metodą dwóch źródeł. Wyznaczono optymalny podział czasu pomiaru częstości zliczeń dla pomiaru jednym i dwoma źródłami. Wyniki pracy mogą być wykorzystane do optymalizacji systemów zliczających fotony lub cząstki

    TEORIA WZMOCNIENIA JEDNOFOLIOWEGO DETEKTORA Z GAZOWYM POWIELANIEM ELEKTRONÓW

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    Gain prediction theory of single foil Gas Electron Multiplier detector was developed. Gas electron multiplier (GEM) detector with single foil was developed. Soft X-ray spectra with an energy of 5.9 keV emitted by the isotope Fe-55 were measured. On this basis, the dependence of gain and energy resolution from the detector voltage was determined. The simple theory of gain dependence on various detector parameters was developed. Preliminary results of the study confirmed the potential usefulness of the GEM detector as a substitute for the multiwire proportional chamber.Opracowano teorię wzmocnienia jednofoliowego detektora z gazowym powielaniem elektronów. Opracowano detektor z gazowym powielaniem elektronów z pojedynczą folią. Zmierzono widmo miękkiego promieniowania X, o energii 5,9 keV, emitowanego przez izotop Fe-55. Na tej podstawie wyznaczono zależność wzmocnienia i energetycznej zdolności rozdzielczej od napięcia zasilającego detektor. Opracowano prosta teorią zależności wzmocnienia od różnych parametrów detektora. Wstępne rezultaty badań potwierdzają potencjalną przydatność detektora GEM jako substytutu wielodrutowej komory proporcjonalnej

    Collins and Sivers asymmetries in muonproduction of pions and kaons off transversely polarised protons

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    Measurements of the Collins and Sivers asymmetries for charged pions and charged and neutral kaons produced in semi-inclusive deep-inelastic scattering of high energy muons off transversely polarised protons are presented. The results were obtained using all the available COMPASS proton data, which were taken in the years 2007 and 2010. The Collins asymmetries exhibit in the valence region a non-zero signal for pions and there are hints of non-zero signal also for kaons. The Sivers asymmetries are found to be positive for positive pions and kaons and compatible with zero otherwise. © 2015

    Measurement of azimuthal hadron asymmetries in semi-inclusive deep inelastic scattering off unpolarised nucleons

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    Spin-averaged asymmetries in the azimuthal distributions of positive and negative hadrons produced in deep inelastic scattering were measured using the CERN SPS longitudinally polarised muon beam at 160GeV/c and a 6LiD target. The amplitudes of the three azimuthal modulations cos φh, cos 2φh and sin φh were obtained binning the data separately in each of the relevant kinematic variables x, z or pTh and binning in a three-dimensional grid of these three variables. The amplitudes of the cos φh and cos 2φh modulations show strong kinematic dependencies both for positive and negative hadrons. © 2014 CERN for the benefit of the COMPASS Collaboration

    Vol. 42 - Measurement based characterisation and modeling of micropixel avalanche photodiodes

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    This dissertation contains a detailed research of new types of Silicon Photomultipliers which have been developed at the beginning of this century. The author was responsible for measuring new types of silicon photomultipliers (SiPM) which were planned to be used as photosensors in the new calorimeter—ECAL0 in COMPASS experiment in CERN. The prototype of the calorimeter was equipped with Micropixel Avalanche Photodiodes (MAPD detectors from Zecotek), the final detector uses MPPC S12572-010 photosensors from Hamamatsu. First chapter contains a detailed description of both detectors and examples of their usage in high energy physics experiments. To perform measurements and simulations of detectors, a special automated system with low noise front-end electronics has been designed. The thesis contains a description of the system which consists of three subsystems: low noise front-end electronics with data acquisition system, light source and light spot positioning system and temperature regulation system. Work contains a detailed description and schematic of discrete-elements-based charge sensitive amplifier (CSA). Electrical models of both MAPD and MPPC detectors have been proposed and confirmed with electrical measurements of impedance. A set of histogram based measurements has been performed. The main measured parameters are: electron gain, dark rate, relative photon detection efficiency and correlated noise. A new quenching mechanism of MAPD detector was a motivation to measure and analyse the recovery time. The results have shown that MAPD has very long recovery time and non-exponential recovery characteristic. Electron gain measurements showed that electron gain calculated from dark pulses is smaller due to long recovery time. A special care has been taken to measure the parameters uniformity of detectors. One chapter contains results of spacial distribution of parameters measured with both CSA and fast amplifier. Results of scans with histogram collection showed that the PDE (Photon Detection Efficiency) of MAPD is changing over the surface of the detector. Scans of signal shape revealed that the shape of the MAPD signal is dependent on the position of light flux due to thin contact layer. The simulation of contact layer has been performed and compared with measurement data. A big part of this thesis is a model description and Monte Carlo simulations of Geiger discharge probability in SiPM detector. The model has been based on the MPPC detector. The simulation results contain Geiger discharge probability dependency on the applied supply voltage and the position of primary charge and spectral sensitivity simulation of the model. The results of this work could be very useful for experiments willing to use new types of SiPM photosensors in new detectors systems

    The study of radiation damage of EPROM 2764 memory

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    A simple statistical theory of radiation damage of semiconductor memory has been constructed. The radiation damage of EPROM memory has been investigated. The measured number of damaged bytes is significantly lower than the expected number resulting from the purely random distribution of the damaged bits. In this way it has been proven that there is a correlation between the failures of individual memory bits which are located in the same byte
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