234 research outputs found

    A simple radionuclide-driven single-ion source

    Get PDF
    We describe a source capable of producing single barium ions through nuclear recoils in radioactive decay. The source is fabricated by electroplating 148Gd onto a silicon {\alpha}-particle detector and vapor depositing a layer of BaF2 over it. 144Sm recoils from the alpha decay of 148Gd are used to dislodge Ba+ ions from the BaF2 layer and emit them in the surrounding environment. The simultaneous detection of an {\alpha} particle in the substrate detector allows for tagging of the nuclear decay and of the Ba+ emission. The source is simple, durable, and can be manipulated and used in different environments. We discuss the fabrication process, which can be easily adapted to emit most other chemical species, and the performance of the source

    Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 2: The Physics Program for DUNE at LBNF

    Full text link
    The Physics Program for the Deep Underground Neutrino Experiment (DUNE) at the Fermilab Long-Baseline Neutrino Facility (LBNF) is described

    The need, opportunities, and challenges for creating a standardized framework for marine restoration monitoring and reporting

    Get PDF
    Marine ecosystems have been used, impacted by, and managed by human populations for millennia. As ecosystem degradation has been a common outcome of these activities, marine management increasingly considers ecosystem restoration. Currently, there is no coherent data recording format or framework for marine restoration projects. As a result, data are inconsistently recorded and it is difficult to universally track progress, assess restoration's global effectiveness, reduce reporting bias, collect a holistic suite of metrics, and share information. Barriers to developing a unified system for reporting marine restoration outcomes include: reaching agreement on a framework that meets the needs of all users, funding its development and maintenance, balancing the need for ‘ease of use’ and detail, and demonstrating the value of using the framework. However, there are opportunities to leverage arising from the United Nation Decades of Ecosystem Restoration and Science for Sustainable Development and with existing processes already developed by restoration groups (e.g. Global Mangrove Alliance, Society for Ecological Restoration). Here we provide guidelines and a roadmap for how such a framework could be developed and the potential benefits of such an endeavor. We call on practitioners to collaborate to develop such a framework and on governing bodies to commit to making detailed reporting a requirement for restoration project funding. Using a standardized marine restoration monitoring framework would enable the application of adaptive management when projects are not progressing as expected, advance our understanding of the state of worldwide marine restoration, and generate knowledge to advance restoration methodologies

    The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

    Get PDF
    The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

    Talking about Gypsies: the notion of discourse as control.

    Get PDF
    The file attached to this record is the authors final peer reviewed version. The final published version can be found on the publisher's website. http://www.informaworld.com/Gypsies and Travellers are increasingly part of a debate by politicians and the media in the U.K. This discourse is not a benign reflection of events; instead it is part of a complex mechanism of control. There is a difficult relationship between the settled and travelling communities which inhibits political discussion of a strategy for site provision. In this context, the paper examines the links between discourse and control, by paying attention to Foucaultian notions of the ‘gaze’, amongst other explanations. Drawing on findings from analysis of the media, focus groups with Travellers and a case study in one local authority planning consultation exercise, the paper proposes a theoretical explanation for the link between the discourse used around Gypsies and Travellers and the control that is exercised over them, particularly in inhibiting their right to a travelling lifestyle

    Issues of context, capacity and scale: Essential conditions and missing links for a sustainable blue economy

    Get PDF
    Funding: This work was supported by the United Kingdom Research and Innovation (UKRI), Global Challenges Research Fund (GCRF), One Ocean Hub (Grant Ref: NE/S008950/1).The blue economy has roots in the international arena of sustainable development and sets out to unlock opportunities for economy and society whilst protecting and enhancing marine environments. To date there has been no analysis of how this overarching intention for sustainability has influenced the rapid development of blue economy policies at national and regional scales. In this article, we analyse the synergies and conflicts between blue economy policies from a diversity of national and regional policies and the UN Sustainable Development Goals. We show that to maintain critical alignment with targets for sustainability, place-based contextual development of blue economies that meet the needs of all actors is necessary. These needs relate to ensuring resilience against future environmental and political shocks, the maintenance of the ecological basis for thriving blue economies, and capacity development at all levels to support effective and equitable governance. Results indicate that co-production will be important to achieve sustainable blue economies.Publisher PDFPeer reviewe

    Performance of the NOνA Data Acquisition and Trigger Systems for the full 14 kT Far Detector

    Get PDF
    The NOvA experiment uses a continuous, free-running, dead-timeless data acquisition system to collect data from the 14 kT far detector. The DAQ system readouts the more than 344,000 detector channels and assembles the information into an raw unfiltered high bandwidth data stream. The NOvA trigger systems operate in parallel to the readout and asynchronously to the primary DAQ readout/event building chain. The data driven triggering systems for NOvA are unique in that they examine long contiguous time windows of the high resolution readout data and enable the detector to be sensitive to a wide range of physics interactions from those with fast, nanosecond scale signals up to processes with long delayed coincidences between hits which occur at the tens of milliseconds time scale. The trigger system is able to achieve a true 100% live time for the detector, making it sensitive to both beam spill related and off-spill physics

    A xenon gas purity monitor for EXO

    Full text link
    We discuss the design, operation, and calibration of two versions of a xenon gas purity monitor (GPM) developed for the EXO double beta decay program. The devices are sensitive to concentrations of oxygen well below 1 ppb at an ambient gas pressure of one atmosphere or more. The theory of operation of the GPM is discussed along with the interactions of oxygen and other impurities with the GPM's tungsten filament. Lab tests and experiences in commissioning the EXO-200 double beta decay experiment are described. These devices can also be used on other noble gases.Comment: 41 pages, 26 figure
    • …
    corecore