25 research outputs found
Metal-loaded organic scintillators for neutrino physics
Organic liquid scintillators are used in many neutrino physics experiments of
the past and present. In particular for low energy neutrinos when realtime and
energy information are required, liquid scintillators have several advantages
compared to other technologies. In many cases the organic liquid needs to be
loaded with metal to enhance the neutrino signal over background events.
Several metal loaded scintillators of the past suffered from chemical and
optical instabilities, limiting the performance of these neutrino detectors.
Different ways of metal loading are described in the article with a focus on
recent techniques providing metal loaded scintillators that can be used under
stable conditions for many years even in ton scale experiments. Applications of
metal loaded scintillators in neutrino experiments are reviewed and the
performance as well as the prospects of different scintillator types are
compared.Comment: 46 pages, 5 figure
Time Response of Water-based Liquid Scintillator from X-ray Excitation
Water-based liquid scintillators (WbLS) present an attractive target medium
for large-scale detectors with the ability to enhance the separation of
Cherenkov and scintillation signals from a single target. This work
characterizes the scintillation properties of WbLS samples based on LAB/PPO
liquid scintillator (LS). X-ray luminescence spectra, decay profiles, and
relative light yields are measured for WbLS of varying LS concentration as well
as for pure LS with a range of PPO concentrations up to 90 g/L. The
scintillation properties of the WbLS are related to the precursor LAB/PPO:
starting from 90 g/L PPO in LAB before synthesis, the resulting WbLS have
spectroscopic properties that instead match 10 g/L PPO in LAB. This could
indicate that the concentration of active PPO in the WbLS samples depends on
their processing.Comment: 6 pages, 7 figures, 2 tables. Submitted to Materials Advances, a
journal of the Royal Society of Chemistr
Production of Gadolinium-loaded Liquid Scintillator for the Daya Bay Reactor Neutrino Experiment
We report on the production and characterization of liquid scintillators for
the detection of electron antineutrinos by the Daya Bay Reactor Neutrino
Experiment. One hundred eighty-five tons of gadolinium-loaded (0.1% by mass)
liquid scintillator (Gd-LS) and two hundred tons of unloaded liquid
scintillator (LS) were successfully produced from a linear-alkylbenzene (LAB)
solvent in six months. The scintillator properties, the production and
purification systems, and the quality assurance and control (QA/QC) procedures
are described.Comment: 15 pages, 11 figures. Submitted to Nuclear Instruments and Methods in
Physics Research Section
Lifetimes in \u3csup\u3e124\u3c/sup\u3eTe: Examining Critical-Point Symmetry in the Te Nuclei
The Doppler-shift attenuation method following inelastic neutron scattering was used to determine the lifetimes of nuclear levels to 3.3-MeV excitation in 124Te. Level energies and spins, γ-ray energies and branching ratios, and multipole-mixing ratios were deduced from measured γ-ray angular distributions at incident neutron energies of 2.40 and 3.30 MeV, γ-ray excitation functions, and γγ coincidence measurements. The newly obtained reduced transition probabilities and level energies for 124Te were compared to critical-point symmetry model predictions. The E(5) and β4 potential critical-point symmetries were also investigated in 122Te and 126Te
Physics Potential of a Few Kiloton Scale Neutrino Detector at a Deep Underground Lab in Korea
The demand for underground labs for neutrino and rare event search
experiments has been increasing over the last few decades. Yemilab, constructed
in October 2022, is the first deep (1~km) underground lab dedicated to
science in Korea, where a large cylindrical cavern (D: 20~m, H: 20~m) was
excavated in addition to the main caverns and halls. The large cavern could be
utilized for a low background neutrino experiment by a liquid
scintillator-based detector (LSC) where a 2.26 kiloton LS target would be
filled. It's timely to have such a large but ultra-pure LS detector after the
shutdown of the Borexino experiment so that solar neutrinos can be measured
much more precisely. Interesting BSM physics searches can be also pursued with
this detector when it's combined with an electron linac, a proton cyclotron
(IsoDAR source), or a radioactive source. This article discusses the concept of
a candidate detector and the physics potential of a large liquid scintillator
detector.Comment: 63 pages, 36 figures, 8 table
Letter of Intent: Jinping Neutrino Experiment
Jinping Neutrino Experiment (Jinping) is proposed to significantly improve
measurements on solar neutrinos and geoneutrinos in China Jinping Laboratory -
a lab with a number of unparalleled features, thickest overburden, lowest
reactor neutrino background, etc., which identify it as the world-best
low-energy neutrino laboratory. The proposed experiment will have target mass
of 4 kilotons of liquid scintillator or water-based liquid scintillator, with a
fiducial mass of 2 kilotons for neutrino-electron scattering events and 3
kilotons for inverse-beta interaction events. A number of initial sensitivities
studies have been carried out, including on the transition phase for the solar
neutrinos oscillation from the vacuum to the matter effect, the discovery of
solar neutrinos from the carbon-nitrogen-oxygen (CNO) cycle, the resolution of
the high and low metallicity hypotheses, and the unambiguous separation on U
and Th cascade decays from the dominant crustal anti-electron neutrinos in
China.Comment: Proposal for the Jinping Neutrino Experimen
Muon Flux Measurement at China Jinping Underground Laboratory
China Jinping Underground Laboratory (CJPL) is ideal for studying solar-,
geo-, and supernova neutrinos. A precise measurement of the cosmic-ray
background would play an essential role in proceeding with the R\&D research
for these MeV-scale neutrino experiments. Using a 1-ton prototype detector for
the Jinping Neutrino Experiment (JNE), we detected 264 high-energy muon events
from a 645.2-day dataset at the first phase of CJPL (CJPL-I), reconstructed
their directions, and measured the cosmic-ray muon flux to be
cms. The observed angular distributions indicate the leakage of
cosmic-ray muon background and agree with the simulation accounting for Jinping
mountain's terrain. A survey of muon fluxes at different laboratory locations
situated under mountains and below mine shaft indicated that the former is
generally a factor of larger than the latter with the same vertical
overburden. This study provides a convenient back-of-the-envelope estimation
for muon flux of an underground experiment