We report the first measurement of coherent elastic neutrino-nucleus scattering (CEvNS) on argon using a liquid argon detector at the Oak Ridge National Laboratory Spallation Neutron Source. Two ...independent analyses prefer CEvNS over the background-only null hypothesis with greater than 3σ significance. The measured cross section, averaged over the incident neutrino flux, is (2.2±0.7)×10^{-39} cm^{2}-consistent with the standard model prediction. The neutron-number dependence of this result, together with that from our previous measurement on CsI, confirms the existence of the CEvNS process and provides improved constraints on nonstandard neutrino interactions.
The coherent elastic scattering of neutrinos off nuclei has eluded detection for four decades, even though its predicted cross section is by far the largest of all low-energy neutrino couplings. This ...mode of interaction offers new opportunities to study neutrino properties and leads to a miniaturization of detector size, with potential technological applications. We observed this process at a 6.7σ̃ confidence level, using a low-background, 14.6-kilogram CsINa scintillator exposed to the neutrino emissions from the Spallation Neutron Source at Oak Ridge National Laboratory. Characteristic signatures in energy and time, predicted by the standard model for this process, were observed in high signal-to-background conditions. Improved constraints on nonstandard neutrino interactions with quarks are derived from this initial data set.
Objective:
Synthesis of a series of methylene-imidazolones with complexing groups.
Methods:
The formation of imines with the following 2+3-cycloaddition and recycling. The use of phosphazene to form ...an acyclic analogue. The optical properties were studied with and without ions of metals. The spectrofluorimetric titration was carried out to evaluate the binding constants.
Results and Discussion:
We discovered that for hydroxyquinolinidene-imidazolone and difluorobenzimidazolidene-imidazolone, which practically did not exhibit fluorescence in the free form, a noticeable increase in fluorescence was observed when binding to the Cd
2+
and Zn
2+
cations.
Conclusions:
Two compounds from a new synthesized series were found to be promising fluorescent sensors of cadmium and zinc ions and potential labels for monitoring intracellular processes.
Study of Xe-doping to LAr scintillator Akimov, D; Belov, V; Burenkov, A ...
Journal of physics. Conference series,
01/2017, Letnik:
798, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Liquid argon (LAr) is an inorganic scintillator widely used in experimental physics. In this paper, the experimental study of Xe-doping as a volume-distributed wavelength shifter in LAr is described. ...The efficiency of light collection and the pulse shapes has been measured for the concentrations of Xe in Ar from few ppm to 24−9+16ppm. The stability of the data has been measured for the 24−9+16ppm concentration during 31 hours.
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It is shown that the working volume of the RED-100 two-phase emission detector, which operates in a ground-based laboratory with liquid xenon used as a working substance, is a source of ...single-electron noise signals with a characteristic frequency of ~200 kHz. Possible mechanisms of generation of these noises and methods for their suppression are discussed.
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A combined passive shield of the RED-100 two-phase emission neutrino detector has been developed and built for suppressing the background of external γ rays and neutrons. The shield is composed of ...a 5‑cm-thick copper layer (the inner layer is adjacent to the detector) and a water layer with a total thickness of approximately 70 cm (including the water inside the copper shield). The Monte Carlo simulation of the shielding efficiency has been performed. The obtained attenuation factor of the copper shield for the γ-ray background has been experimentally verified in a laboratory test using a NaI(Tl) scintillator detector. The γ‑ray background rejection factor of the full shield has also been calculated.
An integral method is described for processing xenon used as a working medium in the RED-100 two-phase emission detector constructed in the NRNU MEPhI to study the process of elastic coherent ...neutrino scattering off atomic nuclei. The developed technology for purifying xenon and the detector has made it possible to increase the lifetime of quasi-free electrons in the 205-kg liquid xenon from ≤0.1 to ≥400 μs in fields of 50−500 V/cm. The entire procedure takes approximately 1000 h. The method can be used to process working media for new-generation two-phase emission detectors designed to conduct basic research, in particular, searching for dark matter in the form of weakly interacting massive particles, detecting boron solar neutrinos, and searching for neutrinoless double-beta decay.
The RED-100 (Russian Emission Detector) is being constructed for the experiment to search for elastic coherent neutrino scattering off atomic nuclei. This fundamental process was predicted several ...decades ago by the Standard Model of electroweak interactions but has not been discovered yet. The RED-100 is a two-phase emission xenon detector containing ∼200 kg of the liquid Xe (∼ 100 kg of that is in a fiducial volume). One of the possible sites to carry out the experiment is the SNS (Spallation Neutron Source) facility at Oak Ridge National Laboratory, USA. SNS is the world's most intense pulsed source of neutrinos and unique place to study neutrino properties. The energy spectrum of neutrinos produced at the SNS extends up to ∼ 50 MeV and satisfies coherence condition. These neutrinos give kinetic energies of Xe recoils up to a few tens of keV where the response of nuclear recoils is well-known from neutron calibrations of dark matter detectors. The detector will be deployed in the basement under the experimental hall at a distance of ∼30 meters from the SNS target. The expected signal and background (neutron and gamma) are estimated for this specific location. The detector details, current status and future plans are provided.
A procedure for spark-discharge purification of a liquid xenon sample with a mass of 55 kg is described. The average lifetime of ionization electrons before capture by electronegative impurities in ...liquid xenon increased from ≤ 0.1 μs to ≥ 50 μs for an electric field of 50–500 V/cm as a result of the procedure. The xenon purified with this method is intended for use in the RED-100 detector for observation of the process of coherent elastic neutrino scattering off xenon nuclei.
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