Detection of the Diffuse Supernova Neutrino Background with JUNO

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

Measurement of the θ13 Neutrino Mixing Angle at Daya Bay via Neutron Capture on Hydrogen

Neutrinos exhibit a unique behavior compared to other Standard Model particles: neutrino oscillations. This phenomenon is the periodic change of probability to interact with certain lepton flavors as they propagate. Measuring the oscillation parameters accurately is crucial to exploring the unanswered questions related to neutrino physics, most notably the possibility that these particles violate the CP symmetry or that there are more than three generations of them.The Daya Bay Reactor Neutrino Experiment is known for making the first unambiguous determination of the non-zero value of the θ13 mixing angle and producing the most precise measurements of this parameter ever since. Located in Southern China, Daya Bay utilizes eight strategically placed identically-designed detectors to measure the disappearance ofelectron antineutrinos from six nuclear reactor cores. The antineutrino interactions are identified through the double coincidence signature of the inverse beta decay. The neutron from this interaction can get captured on a nucleus of either gadolinium (nGd) or hydrogen (nH). Given that the statistical samples are entirely separate and the systematics largely decoupled, the nH and nGd measurements are virtually independent of one another. This makes the nH analysis valuable as a precise cross-check to the nGd analysis.Daya Bay’s world-leading measurement of θ13 is the result of analyzing the former. The measurement of the latter sample is presented in this thesis, including the event selection, removal of background events, evaluation of the systematic uncertainties, and fitting procedure, ultimately leading to the best fit results of sin2 2θ13 = 0.0776 ± 0.0053 and∆m2 ee = (2.80 ± 0.14) × 10−3 eV2. This measurement is among the second most precise measurements of θ13 globally

Ergonomics in surgical environments

The majority of work-related musculoskeletal disorders (WRMDs) in surgery are mostly related to sustained position and awkward postures, forcing non-natural gestures in surgeon ́s body.This arti- cle points to describe the different ailments studied during surgical tasks over the years: causes which increase the discomfort and fatigue, and effects related with them, in order highlight the cur- rent working conditions and how might be improved. To do that, a research is done to understand the main issues related on full body ailments and how is have been evaluated in different types of surgery, for which, the lead postural analysis technologies are presented, understanding Rapid Upper Limb Assessment system (RULA) the most suitable method to stablish priorities for preven- tive/corrective actions.Knowing the ailment ́s causes it have been necessary to define the critical points related with the causes, as instrumentation design, regulations in operating tables and chairs, pedal drives, and other surgical elements that require a ergonomic improvements, so that, the main design guidelines have been col- lected in this document and have been compared with a sample of current products available in the market, with the purpose of knowing the degree of implication between the requirements re- quested by the surgical teams and the companies dedicated to their design

The Design and Sensitivity of JUNO's scintillator radiopurity pre-detector OSIRIS

The OSIRIS detector is a subsystem of the liquid scintillator fillling chain of the JUNO reactor neutrino experiment. Its purpose is to validate the radiopurity of the scintillator to assure that all components of the JUNO scintillator system work to specifications and only neutrino-grade scintillator is filled into the JUNO Central Detector. The aspired sensitivity level of $10^{-16}$ g/g of $^{238}$U and $^{232}$Th requires a large ($\sim$20 m$^3$) detection volume and ultralow background levels. The present paper reports on the design and major components of the OSIRIS detector, the detector simulation as well as the measuring strategies foreseen and the sensitivity levels to U/Th that can be reached in this setup

JUNO Physics and Detector

The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton LS detector at 700-m underground. An excellent energy resolution and a large fiducial volume offer exciting opportunities for addressing many important topics in neutrino and astro-particle physics. With 6 years of data, the neutrino mass ordering can be determined at 3-4 sigma and three oscillation parameters can be measured to a precision of 0.6% or better by detecting reactor antineutrinos. With 10 years of data, DSNB could be observed at 3-sigma; a lower limit of the proton lifetime of 8.34e33 years (90% C.L.) can be set by searching for p->nu_bar K^+; detection of solar neutrinos would shed new light on the solar metallicity problem and examine the vacuum-matter transition region. A core-collapse supernova at 10 kpc would lead to ~5000 IBD and ~2000 (300) all-flavor neutrino-proton (electron) scattering events. Geo-neutrinos can be detected with a rate of ~400 events/year. We also summarize the final design of the JUNO detector and the key R&D achievements. All 20-inch PMTs have been tested. The average photon detection efficiency is 28.9% for the 15,000 MCP PMTs and 28.1% for the 5,000 dynode PMTs, higher than the JUNO requirement of 27%. Together with the >20 m attenuation length of LS, we expect a yield of 1345 p.e. per MeV and an effective energy resolution of 3.02%/\sqrt{E (MeV)}$ in simulations. The underwater electronics is designed to have a loss rate <0.5% in 6 years. With degassing membranes and a micro-bubble system, the radon concentration in the 35-kton water pool could be lowered to <10 mBq/m^3. Acrylic panels of radiopurity <0.5 ppt U/Th are produced. The 20-kton LS will be purified onsite. Singles in the fiducial volume can be controlled to ~10 Hz. The JUNO experiment also features a double calorimeter system with 25,600 3-inch PMTs, a LS testing facility OSIRIS, and a near detector TAO

JUNO sensitivity to low energy atmospheric neutrino spectra

Atmospheric neutrinos are one of the most relevant natural neutrino sources that can be exploited to infer properties about cosmic rays and neutrino oscillations. The Jiangmen Underground Neutrino Observatory (JUNO) experiment, a 20 kton liquid scintillator detector with excellent energy resolution is currently under construction in China. JUNO will be able to detect several atmospheric neutrinos per day given the large volume. A study on the JUNO detection and reconstruction capabilities of atmospheric $\nu_e$ and $\nu_\mu$ fluxes is presented in this paper. In this study, a sample of atmospheric neutrino Monte Carlo events has been generated, starting from theoretical models, and then processed by the detector simulation. The excellent timing resolution of the 3'' PMT light detection system of JUNO detector and the much higher light yield for scintillation over Cherenkov allow to measure the time structure of the scintillation light with very high precision. Since $\nu_e$ and $\nu_\mu$ interactions produce a slightly different light pattern, the different time evolution of light allows to discriminate the flavor of primary neutrinos. A probabilistic unfolding method has been used, in order to infer the primary neutrino energy spectrum from the detector experimental observables. The simulated spectrum has been reconstructed between 100 MeV and 10 GeV, showing a great potential of the detector in the atmospheric low energy region

JUNO Physics Prospects

JUNO is a multipurpose underground neutrino observatory being constructed in the south of China. The main detector, with a 20 kton liquid scintillator target instrumented with about 18k 20" PMT and about 26k 3" PMT, will be strategically located 53 km from the Taishan and Yangjiang Nuclear Power Plants. Using reactor antineutrinos, JUNO will be able to measure several neutrino oscillation parameters with sub-percent precision as well as to determine the neutrino mass ordering to ∼3 over 6 years of operation. Furthermore, JUNO will have a broad physics program, ranging from studying neutrinos from other sources, such as solar and supernova neutrinos, to searching for BSM physics such as proton decay. This talk will give an overview on the JUNO's broad physics potential

Damping signatures at JUNO, a medium-baseline reactor neutrino oscillation experiment

Abstract We study damping signatures at the Jiangmen Underground Neutrino Observatory (JUNO), a medium-baseline reactor neutrino oscillation experiment. These damping signatures are motivated by various new physics models, including quantum decoherence, nu(3) decay, neutrino absorption, and wave packet decoherence. The phenomenological effects of these models can be characterized by exponential damping factors at the probability level. We assess how well JUNO can constrain these damping parameters and how to disentangle these different damping signatures at JUNO. Compared to current experimental limits, JUNO can significantly improve the limits on tau(3)/m(3) in the nu(3) decay model, the width of the neutrino wave packet sigma(x), and the intrinsic relative dispersion of neutrino momentum sigma(rel)

Mass Testing and Characterization of 20-inch PMTs for JUNO

Main goal of the JUNO experiment is to determine the neutrino mass ordering using a 20kt liquid-scintillator detector. Its key feature is an excellent energy resolution of at least 3 % at 1 MeV, for which its instruments need to meet a certain quality and thus have to be fully characterized. More than 20,000 20-inch PMTs have been received and assessed by JUNO after a detailed testing program which began in 2017 and elapsed for about four years. Based on this mass characterization and a set of specific requirements, a good quality of all accepted PMTs could be ascertained. This paper presents the performed testing procedure with the designed testing systems as well as the statistical characteristics of all 20-inch PMTs intended to be used in the JUNO experiment, covering more than fifteen performance parameters including the photocathode uniformity. This constitutes the largest sample of 20-inch PMTs ever produced and studied in detail to date, i.e. 15,000 of the newly developed 20-inch MCP-PMTs from Northern Night Vision Technology Co. (NNVT) and 5,000 of dynode PMTs from Hamamatsu Photonics K. K.(HPK)