2,184 research outputs found

    Macroporous silicon membranes as electron and x-ray transmissive windows

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    Macroporous silicon membranes are fabricated whose pores are terminated with 60 nm thin silicon dioxide shells. The transmission of electrons with energies of 5 kV-25 kV through these membranes was investigated reaching a maximum of 22% for 25 kV. Furthermore, the transmission of electromagnetic radiation ranging from the far-infrared to the x-ray region was determined. The results suggest the application of the membrane as window material for electron optics and energy dispersive x-ray detectors

    Muon capture on nuclei with N > Z, random phase approximation, and in-medium renormalization of the axial-vector coupling constant

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    We use the random phase approximation to describe the muon capture rate on 44{}^{44}Ca,48{}^{48}Ca, 56{}^{56}Fe, 90{}^{90}Zr, and 208{}^{208}Pb. With 40{}^{40}Ca as a test case, we show that the Continuum Random Phase Approximation (CRPA) and the standard RPA give essentially equivalent descriptions of the muon capture process. Using the standard RPA with the free nucleon weak form factors we reproduce the experimental total capture rates on these nuclei quite well. Confirming our previous CRPA result for the N=ZN = Z nuclei, we find that the calculated rates would be significantly lower than the data if the in-medium quenching of the axial-vector coupling constant were employed.Comment: submitted to Phys. Rev.

    Impact of IT Service Management Frameworks on the IT Organization An Empirical Study on Benefits, Challenges, and Processes

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    Over 90 percent of companies are estimatedto use IT Service Management(ITSM) frameworks, yet there is little researchon their benefits to the InformationTechnology (IT) department andthe business units. An international surveyof 491 firms was conducted to assessthe benefits of the IT InfrastructureLibrary (ITIL), the de-facto ITSM framework,specifically on how these benefitsevolve as companies increase theiradoption of the ITIL model. Also studiedare the perception of challenges ofthe implementation and the number ofITIL processes implemented in relationto the progress of the adoption of ITIL.Results indicate that as the maturity ofimplementation increases, the perceptionof challenges decreases. Findingsalso showthat as thematurity of implementationincreases, the number of realizedbenefits increases, as well as thenumber of implemented ITIL processes.Implications for practitioners and researchersare also discussed

    ITIL and the Creation of Benefits: An Empirical Study on Benefits, Challenges and Processes

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    Over 90 percent of companies are estimated to use IT Service Management (ITSM) frameworks, yet there is little research on their benefits to the Information Technology (IT) department and the business units. An international survey of 503 firms was conducted to examine the benefits of the IT Infrastructure Library (ITIL), the de-facto ITSM framework, specifically on how these benefits evolve as companies increase their adoption of the ITIL model. Also studied are the perception of challenges of the implementation and the number of ITIL processes implemented in relation to the progress of the adoption of ITIL. Results indicate that as the maturity of implementation increases, the perception of challenges decreases. Findings also show that as the maturity of implementation increases, the number of realized benefits increases, as well as the number of implemented ITIL processes. Implications for practitioners and researchers are also discussed.12 page(s

    Neutrino induced transitions between the ground states of the A=12 triad

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    Neutrino induced reactions on 12^{12}C, an ingredient of liquid scintillators, have been studied in several experiments. We show that for currently available neutrino energies, EνE_{\nu} \le 300 MeV, calculated exclusive cross sections 12^{12}Cgs(ν,l)_{gs}(\nu,l)12^{12}Ngs_{gs} for both muon and electron neutrinos are essentially model independent, provided the calculations simultaneously describe the rates of several other reactions involving the same states or their isobar analogs. The calculations agree well with the measured cross sections, which can be therefore used to check the normalization of the incident neutrino spectrum and the efficiency of the detector.Comment: 9 pages REVTEX, 2 postscript figures, text and figures available at http://www.krl.caltech.edu/preprints/MAP.htm

    Signal for supernova νμ\nu_\mu and ντ\nu_\tau neutrinos in water \v{C}erenkov detectors

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    We suggest that photons with energies between 5 and 10 MeV, generated by the (ν,νpγ\nu,\nu'p\gamma) and (ν,νnγ\nu,\nu'n\gamma) reactions on 16^{16}O, constitute a signal which allows a unique identification of supernova νμ\nu_\mu and ντ\nu_\tau neutrinos in water \v{C}erenkov detectors. We calculate the yield of such γ\gamma events and estimate that a few hundred of them would be detected in Superkamiokande for a supernova at 10 kpc distance.Comment: 8 pages, RevTex 3.0, figures and text available at http://www.krl.caltech.edu/preprints/MAP.htm

    Rydberg excitation of a single trapped ion

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    We demonstrate excitation of a single trapped cold 40^{40}Ca+^+ ion to Rydberg levels by laser radiation in the vacuum-ultraviolet at 122 nm wavelength. Observed resonances are identified as 3d2^2D3/2_{3/2} to 51 F, 52 F and 3d2^2D5/2_{5/2} to 64F. We model the lineshape and our results imply a large state-dependent coupling to the trapping potential. Rydberg ions are of great interest for future applications in quantum computing and simulation, in which large dipolar interactions are combined with the superb experimental control offered by Paul traps.Comment: 4 pages, 3 figure

    Neutrino-Nucleus Cross Section Measurements using Stopped Pions and Low Energy Beta Beams

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    Two new facilities have recently been proposed to measure low energy neutrino-nucleus cross sections, the nu-SNS (Spallation Neutron Source) and low energy beta beams. The former produces neutrinos by pion decay at rest, while the latter produces neutrinos from the beta decays of accelerated ions. One of the uses of neutrino-nucleus cross section measurements is for supernova studies, where typical neutrino energies are 10s of MeV. In this energy range there are many different components to the nuclear response and this makes the theoretical interpretation of the results of such an experiment complex. Although even one measurement on a heavy nucleus such as lead is much anticipated, more than one data set would be still better. We suggest that this can be done by breaking the electron spectrum down into the parts produced in coincidence with one or two neutrons, running a beta beam at more than one energy, comparing the spectra produced with pions and a beta beam or any combination of these.Comment: 6 pages, 6 figure

    Towards Managing IT Complexity: An IT Governance Framework to Measure Business-IT Responsibility Sharing and Structural IT Organization

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    For large enterprises, IT governance is a major lever to influence the way how IT enables business. The authors hypothesizethat a part of IT governance, namely business-IT responsibility sharing and structural IT organization, has a strong influenceon IT architecture complexity of large enterprises. IT complexity is challenging CIOs of large enterprises all over the worldday-by-day. Yet, IT complexity so far has been analyzed by scientific research only to a small degree. To prove or falsify thehypothesis that IT governance influences IT architecture complexity, the authors developed concepts to measure both aspectswith a framework. In this research, the concept for business-IT responsibility sharing and its scientific background arepresented. The IT complexity measurement concept is shown, focusing on IT architecture complexity. An outlook for thisresearch, an empirical study that is currently in progress is given

    The role of market orientation and innovation capability in export performance of small-and medium-sized enterprises: a Latin American perspective

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    Purpose - This study aims to extend the existing base of knowledge of proactive and reactive market orientation and innovation capability by testing their impact on the export performance of emerging-market small- and medium-sized enterprises (SMEs) in a Latin American context. Design/methodology/approach - This paper is a replication study, and its data were collected through a survey answered by general, marketing, sales or export managers at 155 Mexican SMEs. The research model was tested using partial least squares. Findings - The study results indicate that innovation capability and reactive market orientation are drivers of export performance in Latin American SMEs. Moreover, proactive market orientation has been found to have an indirect effect on export results. Practical implications - This study highlights to managers of Latin American SMEs the importance of capability development and deployment to improve export performance. Social implications - SMEs enabled by strategic and technological innovation based on current and latent customer needs can advantageously perform in foreign markets and can drive economic growth and social and human development in Latin America. Originality/value - Recent studies have focused on emerging-market enterprises and the necessity of developing dynamic capabilities to achieve internationalisation. This study extends previous research by assessing the robustness and generalizability of drivers in export performance for manufacturing SMEs in Latin America. In particular, it provides empirical insights on the capabilities to develop by Latin American SMEs to achieve better export performance
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