145 research outputs found

    Neutrino Physics with JUNO

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    The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purposeunderground liquid scintillator detector, was proposed with the determinationof the neutrino mass hierarchy as a primary physics goal. It is also capable ofobserving neutrinos from terrestrial and extra-terrestrial sources, includingsupernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos,atmospheric neutrinos, solar neutrinos, as well as exotic searches such asnucleon decays, dark matter, sterile neutrinos, etc. We present the physicsmotivations and the anticipated performance of the JUNO detector for variousproposed measurements. By detecting reactor antineutrinos from two power plantsat 53-km distance, JUNO will determine the neutrino mass hierarchy at a 3-4sigma significance with six years of running. The measurement of antineutrinospectrum will also lead to the precise determination of three out of the sixoscillation parameters to an accuracy of better than 1\%. Neutrino burst from atypical core-collapse supernova at 10 kpc would lead to ~5000inverse-beta-decay events and ~2000 all-flavor neutrino-proton elasticscattering events in JUNO. Detection of DSNB would provide valuable informationon the cosmic star-formation rate and the average core-collapsed neutrinoenergy spectrum. Geo-neutrinos can be detected in JUNO with a rate of ~400events per year, significantly improving the statistics of existing geoneutrinosamples. The JUNO detector is sensitive to several exotic searches, e.g. protondecay via the pK++νˉp\to K^++\bar\nu decay channel. The JUNO detector will providea unique facility to address many outstanding crucial questions in particle andastrophysics. It holds the great potential for further advancing our quest tounderstanding the fundamental properties of neutrinos, one of the buildingblocks of our Universe

    Potential of Core-Collapse Supernova Neutrino Detection at JUNO

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    JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

    Detection of the Diffuse Supernova Neutrino Background with JUNO

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    As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

    Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

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    Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30MM_{\odot} for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

    Relationship between vascular access and angulation of vena cava filter at placement and retrieval: a multicenter retrospective cohort study

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    Background: Inferior vena cava (IVC) filters are commonly used intravascular devices designed to prevent fatal pulmonary embolism (PE), maintaining the IVC filter as centered as possible is fundamental for achieving its filtration function. Objective: This study aimed to characterize the tilt angles of IVC filter between the vascular access of internal jugular vein (IJV) and femoral vein (FV), as well as to identify factors associated with increased or decreased tilt angles between placement and retrieval. Design: This is a multicenter retrospective study. Methods: A multicenter retrospective study was conducted from October 2017 to March 2019. The primary outcome was the change in filter tilt between placement and retrieval. The secondary outcome was the identifications of factors associated with increased or decreased tilt angle. Relevant variables were analyzed using t- tests, Chi-square tests, Fisher’s exact tests, while multivariate logistic regression analysis was used to determine risk factors. Results: A total of 184 eligible patients were included in this study. The IJV group had a lower likelihood of tilt angle over 10° at the time of placement compared to the FVs group (0% versus 12.5%, p  = 0.040). Among the 171 patients with a mean dwell time of 22.1 days, the IJV group had a higher likelihood of tilt angle over 10° than the FVs group (10.3% versus 2.3%, p  = 0.080). The use of FVs access at placement was associated with a higher difference between placement and retrieval filter tilt angles ( p  < 0.01). Multivariate logistic regression analysis showed that hypertension [odds ratio (OR) 0.668; 95% confidence interval (CI) 0.328–1.358, p  = 0.265], cardiologic artery disease (OR 0.537; 95% CI 0.136–2.130, p  = 0.377), cerebral venous disease (OR 0.555; 95% CI 0.186–1.651, p  = 0.290), filter types (OR 1.624; 95% CI 0.851–3.096, p  = 0.141), and IVC filter thrombosis (OR 1.634; 95% CI 0.804–3.323, p  = 0.175) were not associated with increased filter tilt angle. Right side (OR 0.434; 95% CI 0.202–0.930, p  = 0.032) or bilateral lower extremity deep vein thrombosis (LEDVT) (OR 0.383; 95% CI 0.148–0.995, p  = 0.049) were identified as protective factors. Conclusion: IJV access was associated with a lower filter tilt angle at the time of placement, while FVs access was linked to a higher difference between placement and retrieval tilt angles. Right side or bilateral LEDVT were identified as protective factors against increased IVC filter tilt angle

    Bulk Photovoltaic Current Mechanisms in All-Inorganic Perovskite Multiferroic Materials

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    After the discovery of bulk photovoltaic effect more than half a century ago, ferro-electrical and magneto-optical experiments have provided insights into various related topics, revealing above bandgap open voltages and non-central symmetrical current mechanisms. However, the nature of the photon-generated carriers responses and their microscopic mechanisms remain unclear. Here, all-inorganic perovskite Bi0.85Gd0.15Fe1−xMnxO3 thin films were prepared by a sol-gel process and the effects of Gd and Mn co-doped bismuth ferrites on their microtopography, grain boundries, multiferroic, and optical properties were studied. We discovered a simple “proof of principle” type new method that by one-step measuring the leakage current, one can demonstrate the value of photo generated current being the sum of ballistic current and shift current, which are combined to form the so-called bulk photovoltaic current, and can be related to the prototype intrinsic properties such as magneto-optical coupling and ferroelectric polarization. This result has significant potential influence on design principles for engineering multiferroic optoelectronic devices and future photovoltaic industry development

    Endovascular Therapies Using Catheter-Based Thrombectomy or Catheter-Directed Thrombolysis for Acute Non-Cancer Associated Inferior Vena Cava Thrombosis: A Retrospective Cohort Study

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    Objective: To investigate the safety and effectiveness of catheter-based therapy (CBT) compared to conventional catheter-directed thrombosis (CDT) for non-oncological patients with inferior vena cava thrombosis (IVCT), as well to evaluate the differences between CBTs using AngioJet rheolytic thrombectomy (ART) and large lumen catheter aspiration (LLCA). Methods: This retrospective single-center study included eligible patients with IVCT treated with CBTs coupled with/without CDT or CDT alone as the first-line treatment between January 3, 2015 and January 28, 2022. The baseline demographics, comorbidities, clinical characteristics, treatment details, course data were all reviewed. Results: A total of 106 patients (128 limbs) were included, with 42 cases were treated with ART, 30 with LLCA, and 34 with CDT alone. Technical success rates were 100% (128/128), and 95.5% (84/88) limbs treated with CBT subsequently underwent CDT. The mean duration of CDT time and total infusion agent dosage in patients with CBTs were lower than those who underwent CDT alone ( P < .05). Similarities were observed in ART compared to LLCA ( P < .05). At the end of CDT, clinical success was achieved in 85.2% (75/88) of limbs treated with CBTs and 77.5% (31/40) of limbs with CDT alone, and 88.5% (46/52) in ART and 80.6% (29/36) in LLCA. The 12-month follow-up showed slightly lower incidences of recurrent thrombosis (7.7% vs 15.2%) and post-thrombotic syndrome (14.1% vs 21.2%), which persisted in patients who underwent ART compared to LLCA (4.3% vs 12.9% and 8.5% vs 22.6%). Patients who underwent CBTs tended to have lower minor complications (5.6% vs 17.6%) but were at higher risk of transient macroscopic hemoglobinuria (58.3% vs 0%) and recoverable acute kidney injury (11.1% vs 2.9%) compared to CDT alone. These findings were similar in ART compared to LLCA (2.4% vs 10.0%, 100% vs 0%, and 16.7% vs 3.3%, respectively). LLCA seemed to have more hemoglobin losses (10.50 ± 9.20 vs 5.57 ± 10. 42 g/L, P < .05). Conclusion: CBTs coupled with/without CDT are safe and effective in patients with IVCT, reducing the clot burden in a moderate time, restoring blood flow rapidly, minimizing thrombolytic drug requirement and lowering minor bleeding complication compared to CDT alone. ART and LLCA have comparable outcomes but with different adverse event profiles
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