10,521 research outputs found

    Coherent Neutrino Scattering in Dark Matter Detectors

    Full text link
    Coherent elastic neutrino- and WIMP-nucleus interaction signatures are expected to be quite similar. This paper discusses how a next generation ton-scale dark matter detector could discover neutrino-nucleus coherent scattering, a precisely-predicted Standard Model process. A high intensity pion- and muon- decay-at-rest neutrino source recently proposed for oscillation physics at underground laboratories would provide the neutrinos for these measurements. In this paper, we calculate raw rates for various target materials commonly used in dark matter detectors and show that discovery of this interaction is possible with a 2 ton⋅\cdotyear GEODM exposure in an optimistic energy threshold and efficiency scenario. We also study the effects of the neutrino source on WIMP sensitivity and discuss the modulated neutrino signal as a sensitivity/consistency check between different dark matter experiments at DUSEL. Furthermore, we consider the possibility of coherent neutrino physics with a GEODM module placed within tens of meters of the neutrino source.Comment: 8 pages, 4 figure

    Photodegradation Mechanisms of Tetraphenyl Butadiene Coatings for Liquid Argon Detectors

    Get PDF
    We report on studies of degradation mechanisms of tetraphenyl butadiene (TPB) coatings of the type used in neutrino and dark matter liquid argon experiments. Using gas chromatography coupled to mass spectrometry we have detected the ultraviolet-blocking impurity benzophenone (BP). We monitored the drop in performance and increase of benzophenone concentration in TPB plates with exposure to ultraviolet (UV) light, and demonstrate the correlation between these two variables. Based on the presence and initially exponential increase in the concentration of benzophenone observed, we propose that TPB degradation is a free radical-mediated photooxidation reaction, which is subsequently confirmed by displaying delayed degradation using a free radical inhibitor. Finally we show that the performance of wavelength-shifting coatings of the type envisioned for the LBNE experiment can be improved by 10-20%, with significantly delayed UV degradation, by using a 20% admixture of 4-tert-Butylcatechol.Comment: 12 pages, 9 figures. Submitted to JINS

    Simultaneous Kummer congruences and E∞\mathbb{E}_\infty-orientations of KO and tmf

    Full text link
    Building on results of M. Ando, M.J. Hopkins and C. Rezk, we show the existence of uncountably many E∞\mathbb{E}_\infty-String orientations of real K-theory KO and of topological modular forms tmf, generalizing the A^\hat{A}- (resp. the Witten) genus. Furthermore, the obstruction to lifting an E∞\mathbb{E}_\infty-String orientations from KO to tmf is identified with a classical Iwasawa-theoretic condition. The common key to all these results is a precise understanding of the classical Kummer congruences, imposed for all primes simultaneously. This result is of independent arithmetic interest.Comment: final versio

    Synthesis, physical properties, antimicrobial potentials of some mixed antibiotics complexed with transition metals and their effects on alkaline phosphatase activities of selected rat tissues

    Get PDF
    Mixed ligand metal complexes of chloramphenicol and oxytetracycline were prepared by using Ni(II), Co(II) and Fe(III) metal chloride hexahydrate. They were characterized based on some physical technique and spectroscopic analysis such as AAS, UV, and IR spectroscopy. Based on the analytical and spectroscopic data, the complexes were proposed to have the formulae [ML1L2](Cl)n (where M = Ni(II), Co(II), Fe(III); L1 = chloramphenicol, L2 = oxytetracycline and n = 2 - 3). IR spectra suggested that both L1 and L2 coordinated to the metal ions in a terdentate manner with ďż˝(O-H), ďż˝(C=O) and ďż˝(N-H) as donor sites in each of the ligands. The complexes were proposed to be of octahedral. The synthesized complexes, in compares to their ligands, were screened for their antibacterial activity against isolated strains of Escherichia coli, Staphylococcus aureus and Klebsiella pneumonia by using diffusion method. The activity data showed the metal complexes to be more potent antibacterial than the parent drugs against the three species. Toxicology tests against some tissues of albino rat (Rattus novergicuss) revealed toxicity of the complexes as compared to the parent drugs. Ni(II) complex was found to possess no significant difference (P > 0.05) in alkaline phosphatase from both homogenates of liver and kidney and rat serum. However, Co(II) and Fe(III) complexes were found to significantly increase (P < 0.05) alkaline phosphatase from homogenates of liver and kidney tissues of the tested doses but there was no significant difference (P > 0.05) in alkaline phosphatase from rat serum

    Measuring Active-to-Sterile Neutrino Oscillations with Neutral Current Coherent Neutrino-Nucleus Scattering

    Full text link
    Light sterile neutrinos have been introduced as an explanation for a number of oscillation signals at Δm2∼1\Delta m^2 \sim 1 eV2^2. Neutrino oscillations at relatively short baselines provide a probe of these possible new states. This paper describes an accelerator-based experiment using neutral current coherent neutrino-nucleus scattering to strictly search for active-to-sterile neutrino oscillations. This experiment could, thus, definitively establish the existence of sterile neutrinos and provide constraints on their mixing parameters. A cyclotron-based proton beam can be directed to multiple targets, producing a low energy pion and muon decay-at-rest neutrino source with variable distance to a single detector. Two types of detectors are considered: a germanium-based detector inspired by the CDMS design and a liquid argon detector inspired by the proposed CLEAR experiment.Comment: 10 pages, 7 figure

    Media(ted) fabrications: How the science-media symbiosis helped ‘sell’ cord banking

    Get PDF
    This paper considers the problematic role of the science–media symbiosis in the dissemination of misleading and emotionally manipulative information regarding services offered by CordBank, New Zealand's only umbilical cord blood banking facility. As this case study illustrates, the growing reliance of health and science reporters on the knowledge capital of medical specialists, biogenetic researchers, and scientists potentially enhances the ability of ‘expert’ sources to set the agenda for media representations of emerging medical and scientific developments, and may undermine the editorial independence of journalists and editors, many of whom in this case failed to critically evaluate deeply problematic claims regarding the current and future benefits of cord banking. Heavy reliance on established media frames of anecdotal personalization and technoboosterism also reinforced a proscience journalistic culture in which claims by key sources were uncritically reiterated and amplified, with journalistic assessments of the value of cord banking emphasizing potential benefits for individual consumers. It is argued that use of these media frames potentially detracts from due consideration of the broader social, ethical, legal, and health implications of emerging biomedical developments, along with the professional, personal, and increasingly also financial interests at stake in their public promotion, given the growing commercialization of biogenetic technologies

    The structural properties of the multi-layer graphene/4H-SiC(000-1) system as determined by Surface X-ray Diffraction

    Full text link
    We present a structural analysis of the multi-layer graphene-4HSiC(000-1}) system using Surface X-Ray Reflectivity. We show for the first time that graphene films grown on the C-terminated (000-1}) surface have a graphene-substrate bond length that is very short (0.162nm). The measured distance rules out a weak Van der Waals interaction to the substrate and instead indicates a strong bond between the first graphene layer and the bulk as predicted by ab-initio calculations. The measurements also indicate that multi-layer graphene grows in a near turbostratic mode on this surface. This result may explain the lack of a broken graphene symmetry inferred from conduction measurements on this system [C. Berger et al., Science 312, 1191 (2006)].Comment: 9 pages with 6 figure

    I Know I Can: Feeling Confident About Discussing Cancer May Help Couples\u27 Cancer Management

    Get PDF
    Managing chronic illness, especially something like cancer, affects more than the diagnosed person. Cancer also affects partners, families, and loved ones. In our study, we were interested in how cancer affects communication patterns between survivors and their partners. We wanted to apply a model that explains chronic illness management in couples to see if we could determine how parts of a relationship, uncertainty about cancer prognosis, and the confidence people have in talking with partners about the cancer affect couples’ ability to manage the disease
    • …
    corecore