Potential of Core-Collapse Supernova Neutrino Detection at JUNO

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

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

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 30$M_{\odot}$ 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

Méthode de reconstruction des traces basée sur la transformée de Hough pour le trajectographe de l’éxperience de Neutrinos JUNO

The JUNO experiment is a multi-purpose underground liquid scintillation detector with a target mass of 20 kt, and an energy resolution of 3% at 1 MeV. The main objective of JUNO is to determine the neutrino mass hierarchy. Among its parts, JUNO has a muon tracker called Top Tracker. It consists of three plastic scintillator layers. The Top Tracker provides accurate tracking of cosmic muons, which is essential for understanding the cosmogenic background in the detector. This thesis focuses on the calibration of the Top Tracker electronics chain using a test bench and a prototype detector called Muon Telescope. Reconstruction methods using this prototype are extensively discussed.The Hough transform is proposed as an alternative reconstruction method to the official one already implemented in the JUNO software. It shows higher efficiency and shorter runtime in comparison to the existing reconstruction method. These advantages make the Hough Transform a good reconstruction method to be used in the Top Tracker.L’expérience JUNO est un détecteur souterrain polyvalent à scintillation liquide dont la masse cible est de 20 kt et dont la résolution en énergie est de 3% at 1 MeV. L’objectif principal de JUNO est de déterminer la hiérarchie des masses de neutrinos. Le Top Tracker est essentiel pour rejeter le fond cosmogénique dans le détecteur central. Le Top Tracker assure un suivi précis des muons cosmiques en vue d’une détection de bruit pouvant imiter le signal. Cette thèse se concentre sur la calibration de la chaîne électronique du Top Tracker à l’aide d’un banc de test et d’un télescope à muons. Les méthodes de reconstruction appliquées sur ce télescope à muons sont également détaillées. La transformée de Hough a été considérée comme une alternative au logiciel officiel de JUNO souffrant de certains inconvenients. La transformée de Hough montre une plus grande efficacité et un temps d'éxecution plus court en tant que méthode de reconstruction. Ce qui fait de cette méthode à un candidat sérieux pour la reconstruction des traces dans le Top Tracker

Méthode de reconstruction des traces basée sur la transformée de Hough pour le trajectographe de l’éxperience de Neutrinos JUNO

L’expérience JUNO est un détecteur souterrain polyvalent à scintillation liquide dont la masse cible est de 20 kt et dont la résolution en énergie est de 3% at 1 MeV. L’objectif principal de JUNO est de déterminer la hiérarchie des masses de neutrinos. Le Top Tracker est essentiel pour rejeter le fond cosmogénique dans le détecteur central. Le Top Tracker assure un suivi précis des muons cosmiques en vue d’une détection de bruit pouvant imiter le signal. Cette thèse se concentre sur la calibration de la chaîne électronique du Top Tracker à l’aide d’un banc de test et d’un télescope à muons. Les méthodes de reconstruction appliquées sur ce télescope à muons sont également détaillées. La transformée de Hough a été considérée comme une alternative au logiciel officiel de JUNO souffrant de certains inconvenients. La transformée de Hough montre une plus grande efficacité et un temps d'éxecution plus court en tant que méthode de reconstruction. Ce qui fait de cette méthode à un candidat sérieux pour la reconstruction des traces dans le Top Tracker.The JUNO experiment is a multi-purpose underground liquid scintillation detector with a target mass of 20 kt, and an energy resolution of 3% at 1 MeV. The main objective of JUNO is to determine the neutrino mass hierarchy. Among its parts, JUNO has a muon tracker called Top Tracker. It consists of three plastic scintillator layers. The Top Tracker provides accurate tracking of cosmic muons, which is essential for understanding the cosmogenic background in the detector. This thesis focuses on the calibration of the Top Tracker electronics chain using a test bench and a prototype detector called Muon Telescope. Reconstruction methods using this prototype are extensively discussed.The Hough transform is proposed as an alternative reconstruction method to the official one already implemented in the JUNO software. It shows higher efficiency and shorter runtime in comparison to the existing reconstruction method. These advantages make the Hough Transform a good reconstruction method to be used in the Top Tracker

Méthode de reconstruction des traces basée sur la transformée de Hough pour le trajectographe de l’éxperience de Neutrinos JUNO

The JUNO experiment is a multi-purpose underground liquid scintillation detector with a target mass of 20 kt, and an energy resolution of 3% at 1 MeV. The main objective of JUNO is to determine the neutrino mass hierarchy. Among its parts, JUNO has a muon tracker called Top Tracker. It consists of three plastic scintillator layers. The Top Tracker provides accurate tracking of cosmic muons, which is essential for understanding the cosmogenic background in the detector. This thesis focuses on the calibration of the Top Tracker electronics chain using a test bench and a prototype detector called Muon Telescope. Reconstruction methods using this prototype are extensively discussed.The Hough transform is proposed as an alternative reconstruction method to the official one already implemented in the JUNO software. It shows higher efficiency and shorter runtime in comparison to the existing reconstruction method. These advantages make the Hough Transform a good reconstruction method to be used in the Top Tracker.L’expérience JUNO est un détecteur souterrain polyvalent à scintillation liquide dont la masse cible est de 20 kt et dont la résolution en énergie est de 3% at 1 MeV. L’objectif principal de JUNO est de déterminer la hiérarchie des masses de neutrinos. Le Top Tracker est essentiel pour rejeter le fond cosmogénique dans le détecteur central. Le Top Tracker assure un suivi précis des muons cosmiques en vue d’une détection de bruit pouvant imiter le signal. Cette thèse se concentre sur la calibration de la chaîne électronique du Top Tracker à l’aide d’un banc de test et d’un télescope à muons. Les méthodes de reconstruction appliquées sur ce télescope à muons sont également détaillées. La transformée de Hough a été considérée comme une alternative au logiciel officiel de JUNO souffrant de certains inconvenients. La transformée de Hough montre une plus grande efficacité et un temps d'éxecution plus court en tant que méthode de reconstruction. Ce qui fait de cette méthode à un candidat sérieux pour la reconstruction des traces dans le Top Tracker

TAO Conceptual Design Report: A Precision Measurement of the Reactor Antineutrino Spectrum with Sub-percent Energy Resolution

The Taishan Antineutrino Observatory (TAO, also known as JUNO-TAO) is a satellite experiment of the Jiangmen Underground Neutrino Observatory (JUNO). A ton-level liquid scintillator detector will be placed at about 30 m from a core of the Taishan Nuclear Power Plant. The reactor antineutrino spectrum will be measured with sub-percent energy resolution, to provide a reference spectrum for future reactor neutrino experiments, and to provide a benchmark measurement to test nuclear databases. A spherical acrylic vessel containing 2.8 ton gadolinium-doped liquid scintillator will be viewed by 10 m^2 Silicon Photomultipliers (SiPMs) of >50% photon detection efficiency with almost full coverage. The photoelectron yield is about 4500 per MeV, an order higher than any existing large-scale liquid scintillator detectors. The detector operates at -50 degree C to lower the dark noise of SiPMs to an acceptable level. The detector will measure about 2000 reactor antineutrinos per day, and is designed to be well shielded from cosmogenic backgrounds and ambient radioactivities to have about 10% background-to-signal ratio. The experiment is expected to start operation in 2022

The JUNO experiment Top Tracker

20 pagesInternational audienceThe main task of the Top Tracker detector of the neutrino reactor experiment Jiangmen Underground Neutrino Observatory (JUNO) is to reconstruct and extrapolate atmospheric muon tracks down to the central detector. This muon tracker will help to evaluate the contribution of the cosmogenic background to the signal. The Top Tracker is located above JUNO's water Cherenkov Detector and Central Detector, covering about 60% of the surface above them. The JUNO Top Tracker is constituted by the decommissioned OPERA experiment Target Tracker modules. The technology used consists in walls of two planes of plastic scintillator strips, one per transverse direction. Wavelength shifting fibres collect the light signal emitted by the scintillator strips and guide it to both ends where it is read by multianode photomultiplier tubes. Compared to the OPERA Target Tracker, the JUNO Top Tracker uses new electronics able to cope with the high rate produced by the high rock radioactivity compared to the one in Gran Sasso underground laboratory. This paper will present the new electronics and mechanical structure developed for the Top Tracker of JUNO along with its expected performance based on the current detector simulation

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

International audienceCore-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 30$M_{\odot}$ 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

Measuring low energy atmospheric neutrino spectra with the JUNO detector

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 neutrinos 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