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).
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 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.
Because of a high energy of the neutrinoless double-beta decay (0
ν
2
β
) of the isotope
150
Nd and a high value of the daughter-nucleus charge
Z
f
,
150
Nd is one of the most promising isotopes for ...0
ν
2
β
-decay searches. A
150
Nd-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.
At the Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences, Moscow) deployed in the Caucasus mountains, it is proposed to create, at a depth corresponding to 4760 ...mwe, a large-volume neutrino detector on the basis of a liquid scintillator with a target mass of 10 kt. The detector in question is intended for recording natural fluxes of neutrinos whose energy may be as low as 100MeV. Neutrino fluxes from various sources are considered in the present study, and the expected effect in the proposed detector is estimated. The detector hat is being developed at the Baksan Neutrino Observatorywill become part of the world network of neutrino detectors for studying natural neutrino fluxes.
A setup for measuring natural-radioactivity backgrounds and ultralow concentrations of the isotope
14
C in samples of a liquid organic scintillator was created at the low-background laboratory of the ...Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences) at a depth of 4900 mwe. The concentration of the radiocarbon
14C
in a sample of a scintillator based on domestically produced linear alkylbenzene was measured, and it was found that
14
C/
12
C (3.3 ± 0.5) × 10
−17
.
Many extensions of the Standard Model of particle physics explain the dominance of matter over antimatter in our Universe by neutrinos being their own antiparticles. This would imply the existence of ...neutrinoless double-β decay, which is an extremely rare lepton-number-violating radioactive decay process whose detection requires the utmost background suppression. Among the programmes that aim to detect this decay, the GERDA Collaboration is searching for neutrinoless double-β decay of
Ge by operating bare detectors, made of germanium with an enriched
Ge fraction, in liquid argon. After having completed Phase I of data taking, we have recently launched Phase II. Here we report that in GERDA Phase II we have achieved a background level of approximately 10
counts keV
kg
yr
. This implies that the experiment is background-free, even when increasing the exposure up to design level. This is achieved by use of an active veto system, superior germanium detector energy resolution and improved background recognition of our new detectors. No signal of neutrinoless double-β decay was found when Phase I and Phase II data were combined, and we deduce a lower-limit half-life of 5.3 × 10
years at the 90 per cent confidence level. Our half-life sensitivity of 4.0 × 10
years is competitive with the best experiments that use a substantially larger isotope mass. The potential of an essentially background-free search for neutrinoless double-β decay will facilitate a larger germanium experiment with sensitivity levels that will bring us closer to clarifying whether neutrinos are their own antiparticles.
Search for neutrino-less double beta decay of 100 Mo is proposed using active method with Ca 100 MoO 4 scintillation crystals which show the brightest scintillation light among variety of inorganic ...scintillation materials containing Mo. Study of X-ray luminescence and scintillation properties such as energy response, number of photoelectrons/keV, absolute light yield, decay time, pulse shape discrimination and radioactive contamination of CaMoO 4 crystals grown by the Czochralski method with different conditions are presented. Further R&D of resolution optimization, crystal quality improvement and background reduction are underway. Significant improvement of sensitivity to neutrino-less double beta decay can be achieved by using 10 Mo enriched Ca 100 MoO 4 crystals with good energy resolution and low background. Further reduction of background induced by 48 Ca two neutrino double beta decay can be achieved by using 48 Ca depletion. We are planning to install several kilograms of Ca 100 MoO 4 crystals depleted in 48 Ca at underground laboratory for the neutrino-less double beta decay experiment in the near future.
Upgrade for Phase II of the Gerda experiment Agostini, M.; Bakalyarov, A. M.; Balata, M. ...
European physical journal. C, Particles and fields,
05/2018, Letnik:
78, Številka:
5
Journal Article
Recenzirano
Odprti dostop
The
Gerda
collaboration is performing a sensitive search for neutrinoless double beta decay of
76
Ge
at the INFN Laboratori Nazionali del Gran Sasso, Italy. The upgrade of the
Gerda
experiment from ...Phase I to Phase II has been concluded in December 2015. The first Phase II data release shows that the goal to suppress the background by one order of magnitude compared to Phase I has been achieved.
Gerda
is thus the first experiment that will remain “background-free” up to its design exposure (
100 kg
year
). It will reach thereby a half-life sensitivity of more than
10
26
year within 3 years of data collection. This paper describes in detail the modifications and improvements of the experimental setup for Phase II and discusses the performance of individual detector components.
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