Relevant Studies Of Supernova Neutrinos With The JUNO Experiment

The only one fortunate observation of the sparse neutrino data from the Supernova 1987A explosion in the Large Magellanic Cloud is a milestone in both neutrino physics and neutrino astronomy.Currently many worldwide neutrino detectors runnning or under construction have better detection capbilities of core collapse supernova neutrinos,which can provide high statistics,good energy resolution and more accurate flavor information.As one of the future large liquid scintillator detectors,the detetor of Jiangmen Underground Neutrino Observatory(JUNO)is designed with a 20kt fiducial mass.Given a typical galactic distance of 10 kpc and typical core-collapse SN parameters,JUNO will register about 5000 events from the inverse beta decay(IBD),2000 events from all-flavor elastic netrino-proton scattering(pES),as well as more than 300 events from neutrino-electron scattering(eES),and the charge current and neutral current interaction of neutrinos on the 12C nuclei.This thesis proposes a more realistic and accurrate reconstruction of supernova neutrino energy spectra for different channels in the large liquid scintillator detectors with the singular value decomposition(SVD)unfolding method.Then combining the IBD channel with the other two full flavor elastic scattering channels v +p ? v + p and v+ e-? v + e-,it can also separate the flux spectra for different flavor neutrinos.To demonstrate the validity of this approach,we also attempt to reconstruct the neutrino spectra by using the time-integrated neutrino data from the latest numerical simulations of delayed neutrino-driven supernova explosions.Supernova is a rare astronomy scenario and this urges that JUNO detector should record as much information as possible once there is a supernova burst neutrino emission.Therefore,one on board supernova trigger strategy using the IBD channel is suggested in this thesis.The selection criteria of SN IBD events are disscussed with simulation and the electronics logic of this strategy are illustrated.Since the electronics for JUNO experiment is not settled,this thesis also present how to determine the parameters of the supernova trigger strategy and the corresponding supernova false alert rate as well as supernova trigger efficiency.Following this strategy,JUNO can trigger a Supernova event with a similar distance as SN1987A and has the ability to trigger a supernova at?100kpc.Except the energy information,the JUNO can also provide the neutrino time dis-tribution once a supernova triggered.This thesis comes up with a number luminosity distribution parameteriztion for all falvor supernova neutrinos at the source place,ac-cording to the supernova neutrino numerical models of Garching group.As currently the supernova simulation consumes a large mount of time and computing resources,the time distribution parameterization can simplify the phemonenology study for theorists.