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The internal detector background arising in searches for neutrinoless double-beta decay of the isotope Nd from the two-neutrino beta decay of the same isotope is calculated. The calculation is performed for a detector several liter in volume based on a neodymium-doped liquid organic scintillator and implemented in various configurations and at various neodymium concentrations of up to 5.5 g/l. Limits on the detector sensitivity in searches for neutrinoless double-beta decay of the isotope Nd are obtained. [ABSTRACT FROM AUTHOR]

The article reports on the current status of the Baksan Large Neutrino Telescope project and describes some selective results of the first stage of the project, a detector prototype with a liquid scintillator mass of 0.5 tons. The results of the second stage of the project, a prototype with liquid scintillator mass of 5 tons, and project prospects also presented. [ABSTRACT FROM AUTHOR]

Metal-loaded liquid organic scintillators (MeLS) are discussed from the point of view of light yield at high metal loading (Gd, Nd, Zr, In). It is shown that, when metal -diketonates are introduced into the scintillator, its light yield is always lower than when carboxylates are used, which is explained by the structural difference between these complexes. The nature of the metal in some cases (Nd) also affects the light attenuation length and, consequently, the MeLS light yield. The composition of the solvent (the fraction of aromatics in the main solvent) and the degree of purification of the introduced metal complex also have a significant effect on the light yield. [ABSTRACT FROM AUTHOR]

Low background segmented liquid scintillator detector, doped with an indium as a target for solar neutrino registration, can be used for measuring total solar neutrino spectrum including neutrinos. A detector consisting of small modules filled with liquid scintillator in the volume of 1–2 L is considered. Silicon matrices are used for light collection. The background of indium beta-activity is suppressed by triple coincidences. The detector of such a type can measure Be neutrino flux with high accuracy and independently check the measurement performed by the Borexino Collaboration. [ABSTRACT FROM AUTHOR]

Synthine and T-6 propellant are studied as new basic solvents for creating liquid organic scintillators. The light attenuation length in these solvents (both those obtained from the manufacturer and those subjected to chromatographic purification on Al O ) was measured along with the relative light yield of scintillators based on them. The chemical composition of synthine was determined by the method of chromato-mass spectrometry and UV spectrophotometry. A Nd-loaded scintillator ( 9 g/L) based on a synthine–pseudocumene mixture was created, and its light yield (LY 60 ) was measured with respect to a scintillator based on linear alkyl benzene (LAB). [ABSTRACT FROM AUTHOR]

A modification of the LENS (Low Energy Neutrino Spectroscopy) project for spectroscopy of solar neutrinos with energies above about 715 keV on the basis of new technologies and solutions is examined. The respective detector employs In nuclei as a target for neutrinos. The creation of a detector containing about 200 t of a scintillator loaded with 10 t of indium will make it possible to measure, within five years, the energy spectra of solar neutrinos from Be, neutrinos from the CNO cycle, and neutrinos with small systematic errors. The detector was simulated in the form of a set of cells of a liquid scintillator doped with indium (about 10 in weight). Necessary technical conditions for detector cells are formulated, and the possible counting rate for events induced by internal and external backgrounds and characterized by an energy release of 600 to 1600 keV is estimated. It is shown that such a detector is implementable, in principle. [ABSTRACT FROM AUTHOR]

Because of a high energy of the neutrinoless double-beta decay (0ν2β) of the isotope 150Nd and a high value of the daughter-nucleus charge Zf, 150Nd is one of the most promising isotopes for 0ν2β-decay searches. A 150Nd-containing detector on the basis of a liquid organic scintillator permits employing large isotope masses. Requirements on the radiation purity of the neodymium sample used are determined. The possible design of a large-scale detector of this type and expected results are considered. [ABSTRACT FROM AUTHOR]

The efficiency of removing U and Th from a liquid organic scintillator based on linear alkylbenzene (LAB) by stripping with a 0.02 M aqueous solution of aminomethylenediphosphonic acid and by sorption on aluminum oxide and silica gel was studied. A procedure was developed for purification of scintillation additives (2,5-diphenyloxazole, 2-biphenyl-5-phenyloxazole, p-terphenyl) to remove K. [ABSTRACT FROM AUTHOR]

The results of studies of the scintillation-light emission kinetics of liquid scintillators, which are based on linear alkylbenzene (LAB) and pseudocumene (PC) with various scintillating fluors under irradiation with γ quanta from a Cs radioactive source, are presented. The complex multicomponent character of scintillations that is characterized by the fluorescence time constants τ ∼ 2.2-7.0 ns, τ ∼ 4.4-14.7 ns, τ ∼ 13.8-68.8 ns, and τ > 2.2-120.0 ns is demonstrated. [ABSTRACT FROM AUTHOR]

A low-background scintillation setup situated in the Gran Sasso National Laboratory is described. The facility is composed of nine identical cells, each 2 L in volume. The C content of a PXE-based scintillator has been measured using this setup; the value obtained is R(C/C) = (12.6 ± 0.4) × 10. This result can be used for comprehensive investigation of possible C production channels in organic scintillators. [ABSTRACT FROM AUTHOR]

Properties of domestic linear alkylbenzene were subjected to a physicochemical study in order to enable use of this compound as the main solvent in large-volume liquid organic scintillators intended for neutrino experiments. New compositions of Gd-containing liquid scintillators based on linear alkylbenzene were suggested and examined. [ABSTRACT FROM AUTHOR]

n organic liquid In-loaded scintillator based on a salt of carboxylic (2-methyl valeric) acid was developed. At an In loading of ∼50 g/l, the scintillator characteristics were as follows: the light yield was 9000 photons/MeV, and the attenuation length was ∼1.5 m. Operation of a 1-m-long optical module used as a detector prototype was demonstrated. The scintillator stability was tested under low-background conditions of an underground laboratory. [ABSTRACT FROM AUTHOR]

Complexes of Gd with carboxylic acids C4–C9 were prepared, and their properties were studied: solubility in water and organic solvents in relation to temperature, melting points, and decomposition points. A procedure was developed for removing water from gadolinium 2-methylvalerate Gd(2MVA)3 to a final content not exceeding 0.01%. To increase the solubility of Gd(2MVA)3 in low-polarity organic solvents and to stabilize the resulting organic solutions, it was suggested to add extractants such as 2-methylvaleric acid (H2MVA) or neutral organophosphorus compounds: triisoamylphosphine oxide (TIAPO) or trioctylphosphine oxide (TOPO). Liquid Gd-loaded organic scintillators based on Gd(2MVA)3 solutions with additions of H2MVA, TIAPO, and TOPO in trimethylbenzene (TMB), phenylxylylethane (PXE), and their mixtures with dodecane were prepared. Long-term tests (up to 2 years) of the stability of the optical properties of the scintillators obtained proved their stability at temperatures of up to 30°C. At elevated temperatures (40°C and higher), the scintillators degrade. The previously made suggestion that water in the scintillator negatively affects its optical properties in prolonged storage was confirm [ABSTRACT FROM AUTHOR]