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 Physics , 2015, Abstract: We has set up a light scattering spectrometer to study the depolarization of light scattering in linear alkylbenzene. From the scattering spectra it can be unambiguously shown that the depolarized part of light scattering belongs to Rayleigh scattering. The additional depolarized Rayleigh scattering can make the effective transparency of linear alkylbenzene much better than it was expected. Therefore sufficient scintillation photons can transmit through the large liquid scintillator detector of JUNO. Our study is crucial to achieving the unprecedented energy resolution 3\%/$\sqrt{E\mathrm{(MeV)}}$ for JUNO experiment to determine the neutrino mass hierarchy. The spectroscopic method can also be used to judge the attribution of the depolarization of other organic solvents used in neutrino experiments.
 Borexino Collaboration Physics , 2004, Abstract: We report on the study of a new liquid scintillator target for neutrino interactions in the framework of the research and development program of the BOREXINO solar neutrino experiment. The scintillator consists of 1,2-dimethyl-4-(1-phenylethyl)-benzene (phenyl-o-xylylethane, PXE) as solvent and 1,4-diphenylbenzene (para-Terphenyl, p-Tp) as primary and 1,4-bis(2-methylstyryl)benzene (bis-MSB) as secondary solute. The density close to that of water and the high flash point makes it an attractive option for large scintillation detectors in general. The study focused on optical properties, radioactive trace impurities and novel purification techniques of the scintillator. Attenuation lengths of the scintillator mixture of 12 m at 430 nm were achieved after purification with an alumina column. A radio carbon isotopic ratio of C-14/C-12 = 9.1 * 10^{-18}$has been measured in the scintillator. Initial trace impurities, e.g. U-238 at 3.2 * 10^{-14} g/g could be purified to levels below 10^{-17} g/g by silica gel solid column purification.  Physics , 2014, Abstract: We examine the prospects for detecting supernova$\nu_e$in JUNO, RENO-50, LENA, or other approved or proposed large liquid scintillator detectors. The main detection channels for supernova$\nu_e$in a liquid scintillator are its elastic scattering with electrons and its charged-current interaction with the$^{12}$C nucleus. In existing scintillator detectors, the numbers of events from these interactions are too small to be very useful. However, at the 20-kton scale planned for the new detectors, these channels become powerful tools for probing the$\nu_e$emission. We find that the$\nu_e$spectrum can be well measured, to better than$\sim 40\%$precision for the total energy and better than$\sim 25\%$precision for the average energy. This is adequate to distinguish even close average energies, e.g., 11 MeV and 14 MeV, which will test the predictions of supernova models. In addition, it will help set constraints on neutrino mixing effects in supernovae by testing non-thermal spectra. Without such large liquid scintillator detectors (or Super-Kamiokande with added gadolinium, which has similar capabilities), supernova$\nu_e$will be measured poorly, holding back progress on understanding supernovae, neutrinos, and possible new physics.  Physics , 2011, DOI: 10.1016/j.astropartphys.2012.02.011 Abstract: We propose the liquid-scintillator detector LENA (Low Energy Neutrino Astronomy) as a next-generation neutrino observatory on the scale of 50 kt. The outstanding successes of the Borexino and KamLAND experiments demonstrate the large potential of liquid-scintillator detectors in low-energy neutrino physics. LENA's physics objectives comprise the observation of astrophysical and terrestrial neutrino sources as well as the investigation of neutrino oscillations. In the GeV energy range, the search for proton decay and long-baseline neutrino oscillation experiments complement the low-energy program. Based on the considerable expertise present in European and international research groups, the technical design is sufficiently mature to allow for an early start of detector realization.  F. L. Villante Physics , 2014, DOI: 10.1016/j.physletb.2015.01.043 Abstract: Neutrinos produced in the Sun by electron capture reactions on$^{13}{\rm N}$,$^{15}{\rm O}$and$^{17}{\rm F}$, to which we refer as ecCNO neutrinos, are not usually considered in solar neutrino analysis since the expected fluxes are extremely low. The experimental determination of this sub-dominant component of the solar neutrino flux is very difficult but could be rewarding since it provides a determination of the metallic content of the solar core and, moreover, probes the solar neutrino survival probability in the transition region at$E_\nu\sim 2.5\,{\rm MeV}\$. In this letter, we suggest that this difficult measure could be at reach for future gigantic ultra-pure liquid scintillator detectors, such as LENA.