129 research outputs found

    The MGDO software library for data analysis in Ge neutrinoless double-beta decay experiments

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    The GERDA and Majorana experiments will search for neutrinoless double-beta decay of germanium-76 using isotopically enriched high-purity germanium detectors. Although the experiments differ in conceptual design, they share many aspects in common, and in particular will employ similar data analysis techniques. The collaborations are jointly developing a C++ software library, MGDO, which contains a set of data objects and interfaces to encapsulate, store and manage physical quantities of interest, such as waveforms and high-purity germanium detector geometries. These data objects define a common format for persistent data, whether it is generated by Monte Carlo simulations or an experimental apparatus, to reduce code duplication and to ease the exchange of information between detector systems. MGDO also includes general-purpose analysis tools that can be used for the processing of measured or simulated digital signals. The MGDO design is based on the Object-Oriented programming paradigm and is very flexible, allowing for easy extension and customization of the components. The tools provided by the MGDO libraries are used by both GERDA and Majorana.Comment: 4 pages, 1 figure, proceedings for TAUP201

    Roughness Signature of Tribological Contact Calculated by a New Method of Peaks Curvature Radius Estimation on Fractal Surfaces

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    This paper proposes a new method of roughness peaks curvature radii calculation and its application to tribological contact analysis as characteristic signature of tribological contact. This method is introduced via the classical approach of the calculation of radius of asperity. In fact, the proposed approach provides a generalization to fractal profiles of the Nowicki's method [Nowicki B. Wear Vol.102, p.161-176, 1985] by introducing a fractal concept of curvature radii of surfaces, depending on the observation scale and also numerically depending on horizontal lines intercepted by the studied profile. It is then established the increasing of the dispersion of the measures of that lines with that of the corresponding radii and the dependence of calculated radii on the fractal dimension of the studied curve. Consequently, the notion of peak is mathematically reformulated. The efficiency of the proposed method was tested via simulations of fractal curves such as those described by Brownian motions. A new fractal function allowing the modelling of a large number of physical phenomena was also introduced, and one of the great applications developed in this paper consists in detecting the scale on which the measurement system introduces a smoothing artifact on the data measurement. New methodology is applied to analysis of tribological contact in metal forming process

    MEG Upgrade Proposal

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    We propose the continuation of the MEG experiment to search for the charged lepton flavour violating decay (cLFV) \mu \to e \gamma, based on an upgrade of the experiment, which aims for a sensitivity enhancement of one order of magnitude compared to the final MEG result, down to the 6×10146 \times 10^{-14} level. The key features of this new MEG upgrade are an increased rate capability of all detectors to enable running at the intensity frontier and improved energy, angular and timing resolutions, for both the positron and photon arms of the detector. On the positron-side a new low-mass, single volume, high granularity tracker is envisaged, in combination with a new highly segmented, fast timing counter array, to track positron from a thinner stopping target. The photon-arm, with the largest liquid xenon (LXe) detector in the world, totalling 900 l, will also be improved by increasing the granularity at the incident face, by replacing the current photomultiplier tubes (PMTs) with a larger number of smaller photosensors and optimizing the photosensor layout also on the lateral faces. A new DAQ scheme involving the implementation of a new combined readout board capable of integrating the diverse functions of digitization, trigger capability and splitter functionality into one condensed unit, is also under development. We describe here the status of the MEG experiment, the scientific merits of the upgrade and the experimental methods we plan to use.Comment: A. M. Baldini and T. Mori Spokespersons. Research proposal submitted to the Paul Scherrer Institute Research Committee for Particle Physics at the Ring Cyclotron. 131 Page

    Trichphyton violaceum and T. soudanese: re-emerging pathogens in Italy, 2005-2013

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    Dermatomycoses due to Trichophyton violaceum are described in Mediterranean Countries, North Africa and in the Horn of Africa where T. soudanense is present too, but it was rare until few years ago in Italy. Aim of the present study was to evaluate an Italian multicenter 9 year (2005-2013) experience concerning these re-emerging pathogens. Fifty three fungal strains were sent from clinical laboratories to the Medical Mycology Committee (CoSM) - Italian Association of Clinical Microbiology (AMCLI) for mycological confirmation. Strains were identified as T. violaceum (23) and T. soudanense (30) by phenotypic and genotypic methods. These dermatophytes present epidemiological (high rate of inter-human transmission, high risk among adopted children coming from countries of either the Horn of Africa or Sub-Saharan Africa also in outbreaks of tinea capitis) and clinical peculiarities (reduced alopecia, presence of exudative lesions) confirming the originality of these \u201cimported\u201d dermatophyte infection

    2νββ2\nu\beta\beta decay of 76^{76}Ge into excited states with GERDA Phase I

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    Two neutrino double beta decay of 76^{76}Ge to excited states of 76^{76}Se has been studied using data from Phase I of the GERDA experiment. An array composed of up to 14 germanium detectors including detectors that have been isotopically enriched in 76^{76}Ge was deployed in liquid argon. The analysis of various possible transitions to excited final states is based on coincidence events between pairs of detectors where a de-excitation γ\gamma ray is detected in one detector and the two electrons in the other. No signal has been observed and an event counting profile likelihood analysis has been used to determine Frequentist 90\,\% C.L. bounds for three transitions: 0g.s.+21+{0^+_{\rm g.s.}-2^+_1}: T1/22ν>T^{2\nu}_{1/2}>1.61023\cdot10^{23} yr, 0g.s.+01+{0^+_{\rm g.s.}-0^+_1}: T1/22ν>T^{2\nu}_{1/2}>3.71023\cdot10^{23} yr and 0g.s.+22+{0^+_{\rm g.s.}-2^+_2}: T1/22ν>T^{2\nu}_{1/2}>2.31023\cdot10^{23} yr. These bounds are more than two orders of magnitude larger than those reported previously. Bayesian 90\,\% credibility bounds were extracted and used to exclude several models for the 0g.s.+01+{0^+_{\rm g.s.}-0^+_1} transition

    Results on ββ\beta\beta decay with emission of two neutrinos or Majorons in 76^{76}Ge from GERDA Phase I

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    A search for neutrinoless ββ\beta\beta decay processes accompanied with Majoron emission has been performed using data collected during Phase I of the GERmanium Detector Array (GERDA) experiment at the Laboratori Nazionali del Gran Sasso of INFN (Italy). Processes with spectral indices n = 1, 2, 3, 7 were searched for. No signals were found and lower limits of the order of 1023^{23} yr on their half-lives were derived, yielding substantially improved results compared to previous experiments with 76^{76}Ge. A new result for the half-life of the neutrino-accompanied ββ\beta\beta decay of 76^{76}Ge with significantly reduced uncertainties is also given, resulting in T1/22ν=(1.926±0.095)1021T^{2\nu}_{1/2} = (1.926 \pm 0.095)\cdot10^{21} yr.Comment: 3 Figure

    The background in the neutrinoless double beta decay experiment GERDA

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    The GERmanium Detector Array (GERDA) experiment at the Gran Sasso underground laboratory (LNGS) of INFN is searching for neutrinoless double beta decay of 76Ge. The signature of the signal is a monoenergetic peak at 2039 keV, the Q-value of the decay, Q_bb. To avoid bias in the signal search, the present analysis does not consider all those events, that fall in a 40 keV wide region centered around Q_bb. The main parameters needed for the neutrinoless double beta decay analysis are described. A background model was developed to describe the observed energy spectrum. The model contains several contributions, that are expected on the basis of material screening or that are established by the observation of characteristic structures in the energy spectrum. The model predicts a flat energy spectrum for the blinding window around Q_bb with a background index ranging from 17.6 to 23.8*10^{-3} counts/(keV kg yr). A part of the data not considered before has been used to test if the predictions of the background model are consistent. The observed number of events in this energy region is consistent with the background model. The background at Q-bb is dominated by close sources, mainly due to 42K, 214Bi, 228Th, 60Co and alpha emitting isotopes from the 226Ra decay chain. The individual fractions depend on the assumed locations of the contaminants. It is shown, that after removal of the known gamma peaks, the energy spectrum can be fitted in an energy range of 200 kev around Q_bb with a constant background. This gives a background index consistent with the full model and uncertainties of the same size
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