Theia would be a novel, "hybrid" optical neutrino detector, with a rich physics program. This paper is intended to provide a brief overview of the concepts and physics reach of Theia. Full details ...can be found in the Theia white paper 1.
Simultaneous observations of Polar Stratospheric Cloud (PSC' aerosol extinction and HNO3 mixing ratios over Scandinavia are examined for January 9–10, 1992. Data measured by the Microwave Limb ...Sounder (MLS', Cryogenic Limb Array Etalon Spectrometer (CLAES', and Improved Stratospheric and Mesospheric Sounder (ISAMS' experiments on the Upper Atmosphere Research Satellite (UARS' are examined at locations adjacent to parcel trajectory positions. Regression coefficients, obtained from Mie calculations, are used to transform aerosol extinctions into aerosol volume densities. Graphs of volume density versus temperature, and importantly, HNO3 mixing ratio versus temperature, show volume increases and simultaneous loss of HNO3 as temperatures decrease. The data is consistent with initial PSC growth processes which transform sulfate droplets into ternary droplets or nitric acid dihydrate (NAD' particles.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
An undersea antineutrino observatory being developed in Hawaii presents excellent potential for neutrino science. The observatory is a 10-kT monolithic, scintillating organic liquid detector for ...deployment in the deep ocean. Its design allows for relocation from one site to another. Positioning the observatory 50-60 km distant from a nuclear reactor complex enables precision measurement of neutrino mixing parameters Δm221, θ12, and, for non-zero θ13, Δm231 and Δm232, possibly leading to determination of neutrino mass hierarchy. At a mid-Pacific location the observatory can measure the flux of neutrinos from the decay series of uranium and thorium primarily in earth's mantle, and performs a sensitive search for a hypothetical natural fission reactor in earth's core. Subsequent deployments at other mid-ocean locations would test lateral heterogeneity of uranium and thorium in earth's mantle. Sites with depth greater than ∼ 5 km allow a relatively background-free measurement of pep and CNO solar neutrinos, probing the energy region marking the transition between matter- and vacuum-dominated oscillations. The observatory provides sensitivity to galactic supernova neutrinos and their potential to reveal neutrino mass hierarchy, and to the diffuse supernova neutrino background. Initial engineering and design studies for this project are complete, an international collaboration of physicists and geologists continues to grow, and a demonstration deployment is in progress.
The High Energy Physics community can benefit from a natural synergy in research activities into next-generation large-scale water and scintillator neutrino detectors, now being studied for remote ...reactor monitoring, discovery and exclusion applications in cooperative nonproliferation contexts. Since approximately 2010, US nonproliferation researchers, supported by the National Nuclear Security Administration (NNSA), have been studying a range of possible applications of relatively large (100 ton) to very large (hundreds of kiloton) water and scintillator neutrino detectors. In parallel, the fundamental physics community has been developing detectors at similar scales and with similar design features for a range of high-priority physics topics, primarily in fundamental neutrino physics. These topics include neutrino oscillation studies at beams and reactors, solar, and geological neutrino measurements, supernova studies, and others. Examples of ongoing synergistic work at U.S. national laboratories and universities include prototype gadolinium-doped water and water-based and opaque scintillator test-beds and demonstrators, extensive testing and industry partnerships related to large area fast position-sensitive photomultiplier tubes, and the development of concepts for a possible underground kiloton-scale water-based detector for reactor monitoring and technology demonstrations. Some opportunities for engagement between the two communities include bi-annual Applied Antineutrino Physics conferences, collaboration with U.S. National Laboratories engaging in this research, and occasional NNSA funding opportunities supporting a blend of nonproliferation and basic science R&D, directed at the U.S. academic community.
When monitoring a reactor site for nuclear nonproliferation purposes, the presence of an unknown or hidden nuclear reactor could be obscured by the activities of a known reactor of much greater power ...nearby. Thus when monitoring reactor activities by the observation of antineutrino emissions, one must discriminate known background reactor fluxes from possible unknown reactor signals under investigation. To quantify this discrimination, we find the confidence to reject the (null) hypothesis of a single proximal reactor, by exploiting directional antineutrino signals in the presence of a second, unknown reactor. In particular, we simulate the inverse beta decay (IBD) response of a detector filled with a 1 kT fiducial mass of Gadolinium-doped liquid scintillator in mineral oil. We base the detector geometry on that of WATCHMAN, an upcoming antineutrino monitoring experiment soon to be deployed at the Boulby mine in the United Kingdom whose design and deployment will be detailed in a forthcoming white paper. From this simulation, we construct an analytical model of the IBD event distribution for the case of one \(4\mathrm{\ GWt}\pm2\%\) reactor 25 km away from the detector site, and for an additional, unknown, 35 MWt reactor 3 to 5 km away. The effects of natural-background rejection cuts are approximated. Applying the model, we predict \(3\sigma\) confidence to detect the presence of an unknown reactor within five weeks, at standoffs of 3 km or nearer. For more distant unknown reactors, the \(3\sigma\) detection time increases significantly. However, the relative significance of directional sensitivity also increases, providing up to an eight week speedup to detect an unknown reactor at 5 km away. Therefore, directionally sensitive antineutrino monitoring can accelerate the mid-field detection of unknown reactors whose operation might otherwise be masked by more powerful reactors in the vicinity.
Geo-reactor models suggest the existence of natural nuclear reactors at different deep-earth locations with loosely defined output power. Reactor fission products undergo beta decay with the emission ...of electron antineutrinos, which routinely escape the earth. Neutrino mixing distorts the energy spectrum of the electron antineutrinos. Characteristics of the distorted spectrum observed at the earth's surface could specify the location of a geo-reactor, discriminating the models and facilitating more precise power measurement. The existence of a geo-reactor with known position could enable a precision measurement of the neutrino oscillation parameter delta-mass-squared.
Accelerator mass spectrometry dating of three 50g samples of marine turtle bone from the basal cultural stratum of the Tongoleleka archaeological site, Lifuka Island, Kingdom of Tonga, South Pacific ...yields results that agree with conventional 14C dates on marine shell. A method for calibrating these dates that takes into account the long distance migrations of marine turtles in the South Pacific is proposed. A sample size greater than 50g is recommended for routine AMS dating of marine turtle bone.
A new multihit digital TDC implemented in a gallium arsenide ASIC Hazen, E.; Dye, S.T.; Gergin, E. ...
IEEE Transactions on Nuclear Science (Institute of Electrical and Electronics Engineers); (United States),
08/1994, Volume:
41, Issue:
4
Journal Article, Conference Proceeding
Peer reviewed
A monolithic multi-hit digital TDC (time-to-digital converter) has been developed for the DUMAND II experiment. This TDC has a 27 channel pipelined architecture, with a 1ns least count. An overview ...of the performance requirements and implementation in a GaAs gate array is described here.< >
Geo-neutrinos and Earth Models Dye, S T; Huang, Y; Lekic, V ...
arXiv (Cornell University),
05/2014
Paper, Journal Article
Open access
We present the current status of geo-neutrino measurements and their implications for radiogenic heating in the mantle. Earth models predict different levels of radiogenic heating and, therefore, ...different geo-neutrino fluxes from the mantle. Seismic tomography reveals features in the deep mantle possibly correlated with radiogenic heating and causing spatial variations in the mantle geo-neutrino flux at the Earth surface. An ocean-based observatory offers the greatest sensitivity to the mantle flux and potential for resolving Earth models and mantle features. Refinements to estimates of the geo-neutrino flux from continental crust reduce uncertainty in measurements of the mantle flux, especially measurements from land-based observatories. These refinements enable the resolution of Earth models using the combined measurements from multiple continental observatories.
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