83 research outputs found
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
Probability of a Solution to the Solar Neutrino Problem Within the Minimal Standard Model
Tests, independent of any solar model, can be made of whether solar neutrino
experiments are consistent with the minimal Standard Model (stable, massless
neutrinos). If the experimental uncertainties are correctly estimated and the
sun is generating energy by light-element fusion in quasi-static equilibrium,
the probability of a standard-physics solution is less than 2%. Even when the
luminosity constraint is abandoned, the probability is not more than 4%. The
sensitivity of the conclusions to input parameters is explored.Comment: PRL, Revtex, 1 figure, 5 page
A Measurement of Gamow-Teller Strength for 176Yb -> 176Lu and the Efficiency of a Solar Neutrino Detector
We report a 0-degree 176Yb(p,n)176Lu measurement at IUCF where we used 120
and 160 MeV protons and the energy dependence method to determine GT matrix
elements relative to the Fermi matrix element which can be calculated model
independently. The data show that there is an isolated concentration of GT
strength in the low lying 1+ states making the proposed Low Energy Neutrino
Spectroscopy (LENS) detector (based on neutrino captures on 176Yb) sensitive to
7Be and pp neutrinos and a promising detector to resolve the solar neutrino
problem.Comment: 11 pages, LATEX, 4 eps figure
Measurement of the solar neutrino capture rate with gallium metal
The solar neutrino capture rate measured by the Russian-American Gallium
Experiment (SAGE) on metallic gallium during the period January 1990 through
December 1997 is 67.2 (+7.2-7.0) (+3.5-3.0) SNU, where the uncertainties are
statistical and systematic, respectively. This represents only about half of
the predicted Standard Solar Model rate of 129 SNU. All the experimental
procedures, including extraction of germanium from gallium, counting of 71Ge,
and data analysis are discussed in detail.Comment: 34 pages including 14 figures, Revtex, slightly shortene
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
The commissioning of the CUORE experiment: the mini-tower run
CUORE is a ton-scale experiment approaching the data taking phase in Gran Sasso National Laboratory. Its primary goal is to search for the neutrinoless double-beta decay in 130Te using 988 crystals of tellurim dioxide. The crystals are operated as bolometers at about 10 mK taking advantage of one of the largest dilution cryostat ever built. Concluded in March 2016, the cryostat commissioning consisted in a sequence of cool down runs each one integrating new parts of the apparatus. The last run was performed with the fully configured cryostat and the thermal load at 4 K reached the impressive mass of about 14 tons. During that run the base temperature of 6.3 mK was reached and maintained for more than 70 days. An array of 8 crystals, called mini-tower, was used to check bolometers operation, readout electronics and DAQ. Results will be presented in terms of cooling power, electronic noise, energy resolution and preliminary background measurements
Results from the Cuore Experiment
The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay that has been able to reach the 1-ton scale. The detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers, each of them made of 52 crystals. The construction of the experiment was completed in August 2016 and the data taking started in spring 2017 after a period of commissioning and tests. In this work we present the neutrinoless double beta decay results of CUORE from examining a total TeO2 exposure of 86.3kg yr, characterized by an effective energy resolution of 7.7 keV FWHM and a background in the region of interest of 0.014 counts/ (keV kg yr). In this physics run, CUORE placed a lower limit on the decay half- life of neutrinoless double beta decay of 130Te > 1.3.1025 yr (90% C. L.). Moreover, an analysis of the background of the experiment is presented as well as the measurement of the 130Te 2vo3p decay with a resulting half- life of T2 2. [7.9 :- 0.1 (stat.) :- 0.2 (syst.)] x 10(20) yr which is the most precise measurement of the half- life and compatible with previous results
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