101 research outputs found
Systematic Comparison of the MINOS Near and Far Detector Readout Systems
The MINOS experiment is a neutrino oscillation baseline experiment intending to use high resolution L/E neutrinos to measure the atmospheric neutrino oscillations parameters to unprecedented precision. Two detectors have been built to realize the measurements, a Near detector, located about 1km downstream from the beam target at the Fermi Laboratory, and a Far detector, located at 736km, at the Soudan Laboratory. The technique relies on the Near detector to measure the un-oscillated neutrino spectrum, while the Far detector measures the neutrino spectrum once oscillated. The comparison between the two measurements is expected to allow MINOS to measure {Delta}m{sup 2} beyond 10% precision level. The Near and Far detectors have been built similarly to minimize possible systematic effects. Both detectors have been endowed with different readout systems, as the beam event rates are very different. The MINOS calibration detector (CalDet), installed at CERN, was instrumented with both readout systems such that they can simultaneously measure and characterize the energy deposition (response and event topology) of incident known particle from test-beams. This thesis presents the investigations to quantify the impact of the performance of both readout systems on the MINOS results using the measurements obtained with CalDet. The relative comparison of the responses of both readout systems have been measured to be consistent with being identical within a systematic uncertainty of 0.6%. The event topologies have been found to be negligibly affected. In addition, the performance of the detector simulations have been thoroughly investigated and validated to be in agreement with data within similar level of uncertainties
Reactor Neutrino Flux Uncertainty Suppression on Multiple Detector Experiments
This publication provides a coherent treatment for the reactor neutrino flux
uncertainties suppression, specially focussed on the latest
measurement. The treatment starts with single detector in single reactor site,
most relevant for all reactor experiments beyond . We demonstrate
there is no trivial error cancellation, thus the flux systematic error can
remain dominant even after the adoption of multi-detector configurations.
However, three mechanisms for flux error suppression have been identified and
calculated in the context of Double Chooz, Daya Bay and RENO sites. Our
analysis computes the error {\it suppression fraction} using simplified
scenarios to maximise relative comparison among experiments. We have validated
the only mechanism exploited so far by experiments to improve the precision of
the published . The other two newly identified mechanisms could
lead to total error flux cancellation under specific conditions and are
expected to have major implications on the global knowledge
today. First, Double Chooz, in its final configuration, is the only experiment
benefiting from a negligible reactor flux error due to a 90\% geometrical
suppression. Second, Daya Bay and RENO could benefit from their partial
geometrical cancellation, yielding a potential 50\% error suppression,
thus significantly improving the global precision today. And
third, we illustrate the rationale behind further error suppression upon the
exploitation of the inter-reactor error correlations, so far neglected. So, our
publication is a key step forward in the context of high precision neutrino
reactor experiments providing insight on the suppression of their intrinsic
flux error uncertainty, thus affecting past and current experimental results,
as well as the design of future experiments
Synergies and Prospects for Early Resolution of the Neutrino Mass Ordering
The measurement of neutrino Mass Ordering (MO) is a fundamental element for
the understanding of leptonic flavour sector of the Standard Model of Particle
Physics. Its determination relies on the precise measurement of and using either neutrino vacuum oscillations, such
as the ones studied by medium baseline reactor experiments, or matter effect
modified oscillations such as those manifesting in long-baseline neutrino beams
(LBB) or atmospheric neutrino experiments. Despite existing MO indication
today, a fully resolved MO measurement (5) is most likely to
await for the next generation of neutrino experiments: JUNO, whose stand-alone
sensitivity is 3, or LBB experiments (DUNE and
Hyper-Kamiokande). Upcoming atmospheric neutrino experiments are also expected
to provide precious information. In this work, we study the possible context
for the earliest full MO resolution. A firm resolution is possible even before
2028, exploiting mainly vacuum oscillation, upon the combination of JUNO and
the current generation of LBB experiments (NOvA and T2K). This opportunity
is possible thanks to a powerful synergy boosting the overall sensitivity where
the sub-percent precision of by LBB experiments is found
to be the leading order term for the MO earliest discovery. We also found that
the comparison between matter and vacuum driven oscillation results enables
unique discovery potential for physics beyond the Standard Model.Comment: Entitled in arXiv:2008.11280v1 as "Earliest Resolution to the
Neutrino Mass Ordering?
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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
Neutrino Physics with JUNO
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 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
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 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
LiquidO: First Opaque Detector for Decay?
International audienceThe novel LiquidO detection for neutrino and rare decay physics has been released for the first time to the international community in the NOW conference (Sept.~2018) in Italy. The presentation summarised the LiquidO potential only and the new detection principle. This document aims to briefly summarise the most important features of LiquidO in the context of its application. Further details are to be provided in forthcoming publications
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