5,021 research outputs found

    Neutron irradiation effect on SiPMs up to Ωneq\Phi_{neq} = 5 ×\times 1014^{14} cm−2^{-2}

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    Silicon Photo-Multipliers (SiPM) are becoming the photo-detector of choice for increasingly more particle detection applications, from fundamental physics to medical and societal applications. One major consideration for their use at high-luminosity colliders is the radiation damage induced by hadrons, which leads to a dramatic increase of the dark count rate. KETEK SiPMs have been exposed to various fluences of reactor neutrons up to Ωneq\Phi_{neq} = 5×\times1014^{14} cm−2^{-2} (1 MeV equivalent neutrons). Results from the I-V, and C-V measurements for temperatures between −-30∘^\circC and ++30∘^\circC are presented. We propose a new method to quantify the effect of radiation damage on the SiPM performance. Using the measured dark current the single pixel occupation probability as a function of temperature and excess voltage is determined. From the pixel occupation probability the operating conditions for given requirements can be optimized. The method is qualitatively verified using current measurements with the SiPM illuminated by blue LED light

    Ethical and compliance-competence evaluation: a key element of sound corporate governance

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    Motivated by the ongoing post-Enron refocusing on corporate governance and the shift by the Financial Services Authority (FSA) in the UK to promoting compliance- competence within the financial services sector, this paper demonstrates how template analysis can be used as a tool for evaluating compliance-competence. Focusing on the ethical dimension of compliance-competence, we illustrate how this can be subjectively appraised. We propose that this evaluation technique could be utilised as a starting point in informing senior management of corporate governance issues and be used to monitor and demonstrate key compliance and ethical aspects of an institution to external stakeholders and regulators

    A Precision Measurement of pp Elastic Scattering Cross Sections at Intermediate Energies

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    We have measured differential cross sections for \pp elastic scattering with internal fiber targets in the recirculating beam of the proton synchrotron COSY. Measurements were made continuously during acceleration for projectile kinetic energies between 0.23 and 2.59 GeV in the angular range 30≀Ξc.m.≀9030 \leq \theta_{c.m.} \leq 90 deg. Details of the apparatus and the data analysis are given and the resulting excitation functions and angular distributions presented. The precision of each data point is typically better than 4%, and a relative normalization uncertainty of only 2.5% within an excitation function has been reached. The impact on phase shift analysis as well as upper bounds on possible resonant contributions in lower partial waves are discussed.Comment: 23 pages 29 figure

    The High Resolution K600 Spectrometer

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    This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

    The K600 Focal Plane Polarimeter

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    This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

    IUCF High Intensity Polarized Ion Source

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    This research was sponsored by the National Science Foundation Grant NSF PHY-931478

    Full-Folding Optical Potentials for Elastic Nucleon-Nucleus Scattering based on Realistic Densities

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    Optical model potentials for elastic nucleon nucleus scattering are calculated for a number of target nuclides from a full-folding integral of two different realistic target density matrices together with full off-shell nucleon-nucleon t-matrices derived from two different Bonn meson exchange models. Elastic proton and neutron scattering observables calculated from these full-folding optical potentials are compared to those obtained from `optimum factorized' approximations in the energy regime between 65 and 400 MeV projectile energy. The optimum factorized form is found to provide a good approximation to elastic scattering observables obtained from the full-folding optical potentials, although the potentials differ somewhat in the structure of their nonlocality.Comment: 21 pages, LaTeX, 17 postscript figure

    Can processes make relationships work? The Triple Helix between structure and action

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    This contribution seeks to explore how complex adaptive theory can be applied at the conceptual level to unpack Triple Helix models. We use two cases to examine this issue – the Finnish Strategic Centres for Science, Technology & Innovation (SHOKs) and the Canadian Business-led Networks of Centres of Excellence (BL-NCE). Both types of centres are organisational structures that aspire to be business-led, with a considerable portion of their activities driven by (industrial) users’ interests and requirements. Reflecting on the centres’ activities along three dimensions – knowledge generation, consensus building and innovation – we contend that conceptualising the Triple Helix from a process perspective will improve the dialogue between stakeholders and shareholders

    Desperately seeking fixedness: practitioners accounts of 'becoming doctoral researchers

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    We draw upon the concept of liminality to explore the experiences of practitioners enrolled on a UK Doctor of Business Administration (DBA) programme. We analyse twenty practitioners’ reflective journals to detail how the DBA liminal space was negotiated. More specifically, we describe how practitioners deal with their struggles of identity incoherence or ‘monsters of doubt’ which are amplified in the DBA context owing to the complex nature of the separation phase of liminality. We identify three broad methods deployed in this endeavour: ‘scaffolding’; ‘putting the past to work’ and ‘bracketing’- which evidence practitioners ‘desperately seeking fixedness’. We make three contributions – first, we provide empirical insights into the experiences of the increasingly significant, but still under researched, DBA student. Second, we develop our understandings of monsters of doubt through illustrating how these are negotiated for learning to progress. Finally, we contribute to wider discussions of ‘becoming’ to demonstrate the simultaneous and paradoxical importance of movement and fixedness in order to learn and become
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