73 research outputs found
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 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
OSIRIS – An online scintillator radiopurity monitor for the JUNO experiment
The Jiangmen Underground Neutrino Observatory (JUNO) currently under construction in China, will be the first multi-kton liquid scintillator detector and has a vast potential for new insights into several fields of neutrino and astroparticle physics. To reach its design sensitivity for detecting reactor and solar neutrinos, a radiopure liquid scintillator is required. For IBD measurements, a radiopurity of 10 g/g is needed for both U and Th, 10 g/g for solar measurements.The Online Scintillator Internal Radioactivity Investigation System (OSIRIS) allows an on-line radiopurity evaluation of the scintillator during the JUNO detector filling over several months. The design of OSIRIS is optimized for tagging Bi-Po and Bi-Po coincidence decays in the decay chains of U and Th, respectively. OSIRIS will also be able to monitor the C and Po levels in the scintillator.To achieve its goals, OSIRIS features a 20 ton liquid scintillator target monitored by 76 intelligent photomultiplier tubes (iPMTs). In this novel design, each iPMT consists of a PMT and its readout electronics mounted on its back. Each hit causing these electronics to trigger is sent to the DAQ as a digitized PMT pulse. A single computer (EventBuilder) is sufficient to combine the data stream into events for further analysis.For the timing and charge calibration of the detector, two optical systems (LED- and LASER-based) are employed. The energy and position calibration of OSIRIS is performed with height-adjustable radioactive sources within the liquid scintillator. These sources cover the crucial energy range for the detection of Bi-Po signals between 0.66 MeV to 2.5 MeV.The general design of the OSIRIS detector and its subsystems is presented in this poster
OSIRIS: The Online Scintillator Internal Radioactivity Investigation System of JUNO
The Online Scintillator Internal Radioactivity Investigation System (OSIRIS) is a 20 ton liquid scintillator (LS) detector. During the months-long filling of the 20 kton JUNO central detector, it will monitor the LS radiopurity, ensuring stringent radiopurity levels needed for the various physics goals of JUNO. This is achieved by exploiting fast Bi-Po coincidences in the U and Th decay chains. The setup is expected to reach sensitivities of 10 g/g or better for both U and Th. OSIRIS will also measure the C and Po levels present in the scintillator. In this poster, the general design of OSIRIS and its different subsystems will be explained. In OSIRIS, a  water-submerged acrylic vessel holding the LS is instrumented by an array of 76 self-triggering intelligent PMTs. Their timing and charge calibration will be performed  with a Laser- and an LED-based system. The calibration of the energy and vertex reconstruction of OSIRIS utilizes height-adjustable radioactive sources within the LS
OSIRIS - The Online Scintillator Internal Radioactivity Investigation System of JUNO
The 20 kton liquid scintillator detector of the Jiangmen Neutrino Underground Observatory, currently under construction in Southern China, has a vast potential for new insights into various fields of (astro-)particle physics. Stringent limits on the liquid scintillator radiopurity are required for several physics goals of JUNO. For both Th and U, a radiopurity of 10 g/g is required for reactor antineutrino measurements, 10 g/g for solar neutrino measurements. An independent detector, the Online Scintillator Internal Radioactivity Investigation System (OSIRIS), will be used to ensure these limits are kept. This talk will present OSIRIS and its sensitivity to Th and U in detail.OSIRIS allows an online radiopurity evaluation of the scintillator during the months-long filling of JUNO. The design of OSIRIS is optimized for tagging fast Bi-Po and Bi-Po coincidence decays in the decay chains of U and Th, respectively. The coincident decay signatures and their rates offer a potent background rejection as well as a direct translation into U-/Th-abundances in the scintillator. OSIRIS will also be able to measure the levels of C in the scintillator, down to a C/C ratio of 10 at 90\% C.L. Furthermore, the level of Po and a possible contamination by Kr can be determined. To achieve its goals, OSIRIS features a water-submerged 20 ton liquid scintillator target monitored by 76 intelligent PMTs (iPMTs). The novel design of the iPMTs allows a triggerless readout scheme with high signal quality. A single computer is sufficient to process the data stream into events for further analysis. The timing and charge calibration of the iPMTs will be performed with Laser- and LED-based systems. The energy and vertex reconstructions will utilise height-adjustable radioactive sources within the liquid scintillator
Radiopurity treatment of the intelligent PMTs for OSIRIS
The Jiangmen Underground Neutrino Observatory (JUNO), currently under construction in Southern China, is expected to yield new insights regarding the mass hierarchy of neutrinos. In order to reach the design sensitivity for detecting reactor and solar neutrinos, a radiopure liquid scintillator is required.The Online Scintillator Internal Radioactivity Investigation System (OSIRIS) allows an on-line quality evaluation of the scintillator during filling of the JUNO detector. It features a 20 ton liquid scintillator target monitored by 76 intelligent photomultiplier tubes (iPMTs).Because contamination with radioactive isotopes might prevent OSIRIS to reach its target sensitivity, the detector has to be cleaned prior to installation. For removing potential production residues from the iPMTs, a cleaning procedure has been developed. In this talk, the construction of the facility using ultra pure water at RWTH Aachen University will be presented
Software trigger optimization for the OSIRIS pre-detector of JUNO
JUNO is a 20 kt liquid scintillator detector under construction in Jiangmen, China, whose goal is to determine the neutrino mass hierarchy. Its data taking is expected to start in 2022. In order to meet the stringent requirements on the radiopurity of the liquid scintillator, the OSIRIS pre-detector is being designed to monitor the liquid scintillator during the several months of filling the large volume of JUNO. OSIRIS will contain 20 ton of scintillator and will be equipped with 76 20-inch PMTs. The data acquisition system will have no global hardware trigger: instead, each PMT will provide a data-stream composed of the digitized PMT pulses, each containing a time stamp. Based on the latter, dedicated software will organize these data streams into events. This talk will discuss the optimization of the event trigger conditions, for the inner liquid scintillator detector as well as outer water Cherenkov detector, considering the expected rates of different radio-active contaminations, cosmogenic muons, and the PMT dark rates
Solar neutrino physics below 2 MeV with Juno
The Juno observatory, currently under construction in Jiangmen (China), is a 20 kt liquid scintillator detector. Thanks to the large fiducial volume, and thus the high statistics collectable, and excellent energy resolution, it represents a compelling opportunity for the detection of solar neutrinos. In order to be able to extract solar neutrino fluxes once data taking has started, a multivariate fitting strategy will be adopted to disentangle neutrino signals from backgrounds present in the detector. The key steps of the analysis is the estimation of signal and background rates and Monte Carlo PDF production including detector response function. The main aspects used to produce such distributions and their exploitation within the fitting procedure are explained in the following presentation. Depending on the level of contaminants within the detector, it will be possible to extract neutrino fluxes more accurately. For this reason, sensitivity studies conducted under varying background scenarios are presented
Reconstruction of atmospheric neutrino events with JUNO
The ordering of the neutrino masses is one of the fundamental open questions in the field of neutrino physics. The Jiangmen Underground Neutrino Observatory (JUNO) is a multipurpose liquid scintillator-based experiment with a target mass of 20 kt. It aims to determine the neutrino mass hierarchy with at least 3σ significance, through a measurement of the oscillation pattern of reactor neutrinos over 53 km baseline.The sensitivity of JUNO to the mass ordering could be enhanced through the atmospheric neutrino channel. As one of the largest LS detectors, JUNO might be able to measure with high precision the atmospheric neutrino events and their oscillation parameters at MeV-scale as well at GeV-scale. This work represents the current methods used in the reconstruction of atmospheric neutrinos with JUNO
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