Factors affecting the stability of gadolinium- and neodymium-loaded liquid organic scintillators intended for use in large-scale experimental facilities for neutrino physics and astrophysics are ...examined. The effect of composition (type and structural formula of gadolinium and neodymium compounds) on the optical properties of such scintillators is analyzed. It is shown that the oxidation of alkylbenzenes is one of the reasons for the degradation (decrease in transparency) of the scintillators. Gadolinium and neodymium compounds may be catalysts for the oxidation processes.
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).
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.
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.
Metal β-diketonates and carboxylates have been studied with the aim to use them in element-containing liquid organic scintillators. Their effect on the light yield and transparency of scintillators ...has been studied. Absorption spectra of neodymium and zirconium β-diketonates and neodymium and gadolinium 3,5,5-trimethylhexanoates have been reported. In terms of specific light yield of scintillators with added β-diketonates and carboxylates, it has been concluded that the high values of specific light yield at large concentrations of β-diketonates (50%) can be achieved only on addition of considerable amounts of scintillation additives (up to 100 g/L). The stability of metal-containing scintillators related to the structure of added compounds, purity of all components of scintillator, and effect of metal carboxylates and β-diketonates on alkylbenzene oxidation have been studied.
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.
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.
The energy resolution is calculated for a neodymium-containing liquid organic scintillation detector (Nd-OS) with a volume of several liters to search for neutrinoless double beta decay of
150
Nd as ...a function of the neodymium concentration up to 5 g/L. The results are presented in detailed tables and graphs.
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