We study the influence of the temperature and composition of the feed water of ammonia–hydrazine control on the corrosion-electrochemical behavior of 08Kh18N10T stainless steel. It is shown that, as ...temperature increases from 25 to 300°С, the corrosion currents increase by more than an order of magnitude for hydrazine concentrations of 0–2.0 mg/kg, by 1.5–2 orders of magnitude depending on the concentration of chlorides, and by two orders of magnitude within the рН range 6.9–9.0. We plot the dependences of the susceptibility of steel to pitting and repassivation on temperature, on the concentrations of hydrazine and chloride ions, and on the рН value. It is shown that, for a content of chloride ions of 2.0 mg/kg and рН 6.9, the analyzed steel is most susceptible to the initiation of pits within the range 25–300°С.
The Silicon Photomultiplier (SiPM) is a novel semiconducting photodetector which can detect single photons. It consists of many microcells (pixels) operating in the so-called Geiger mode. At present, ...there are two principal designs among such devices: surface pixel and deeply buried pixel (microwell) structures. The cellular structure decreases the device’s effective photosensitive area, expressed in terms of the geometrical fill factor. It is very important to take it into account when developing new constructions with high pixel densities that are necessary for increasing the dynamic range. It is believed that the fill factor of deep microwell SiPMs is close to unity. In this work, the technique and results of studying the zonal response of different SiPMs by scanning (moving) with micron laser spot are presented. It is shown that the geometrical fill factor of the deep microwell SiPM is less than 100% when detecting the red light (λ = 632 nm).
Recent Results from Daya Bay Vorobel, V.
Physics of particles and nuclei,
07/2018, Letnik:
49, Številka:
4
Journal Article
Recenzirano
The Daya Bay Reactor Neutrino Experiment was designed to measure θ
13
, the smallest mixing angle in the three-neutrino mixing framework, with unprecedented precision. The experiment consists of ...eight functionally identical detectors placed underground at different baselines from three pairs of nuclear reactors in South China. Since Dec. 2011, the experiment has been running stably for more than 4 years, and has collected the largest reactor anti-neutrino sample to date. Daya Bay greatly improved the precision on θ
13
and made an independent measurement of the effective mass splitting in the electron antineutrino disappearance channel. Daya Bay also performed a number of other precise measurements, such as a high-statistics determination of the absolute reactor antineutrino flux and spectrum, as well as a search for sterile neutrino mixing, among others. The most recent results from Daya Bay are discussed in this paper, as well as the current status and future prospects of the experiment.
Measurement of the background in the NEMO 3 double beta decay experiment Argyriades, J.; Arnold, R.; Augier, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2009, Letnik:
606, Številka:
3
Journal Article
Recenzirano
Odprti dostop
In the double beta decay experiment NEMO 3 a precise knowledge of the background in the signal region is of outstanding importance. This article presents the methods used in NEMO 3 to evaluate the ...backgrounds resulting from most if not all possible origins. It also illustrates the power of the combined tracking-calorimetry technique used in the experiment.
We construct the solution of the problem on the steady-state vibrations of a finite boxed shell of square cross-section with symmetry conditions at the shell ends. We present the dispersion curves, ...find the natural frequencies, and study the stress distribution in the shell. We obtain a simple formula for the approximate analysis of the shell in the case of low-frequency vibrations on the basis of the expansion of the solution in two small parameters and on the Lagrange interpolation formula.
We study the corrosion-electrochemical behavior of 15Kh2NMFA steel in borate-buffered reactor water within the temperature range 22–300°C and establish the relationship between the temperature ...dependences of the corrosion-fatigue crack growth rates and the electrochemical behavior of steel. The influence of the galvanic couple formed by the refreshed and passivated surfaces on the acceleration of growth of corrosion-fatigue cracks is revealed. It is shown that this type of steel is susceptible to passivation in the entire temperature range.
We are reporting about a scintillating fibre tracking detector which is proposed for the precise determination of the absolute luminosity of the CERN LHC at interaction point 1 where the ATLAS ...experiment is located. The detector needs to track protons elastically scattered under
μ
rad
angles in direct vicinity to the LHC beam. It is based on square shaped scintillating plastic fibres read out by multi-anode photomultiplier tubes and is housed in Roman Pots. We describe the design and construction of prototype detectors and the results of a beam test experiment at DESY. The excellent detector performance established in this test validates the detector design and supports the feasibility of the proposed challenging method of luminosity measurement.
Abstract The full data set of the NEMO-3 experiment has been used to measure the half-life of the two-neutrino double beta decay of $$^{100}$$ 100 Mo to the ground state of $$^{100}$$ 100 Ru, ...$$T_{1/2} = \left 6.81 \pm 0.01\,\left( \text{ stat }\right) ^{+0.38}_{-0.40}\,\left( \text{ syst }\right) \right \times 10^{18}$$ T1/2=6.81±0.01stat-0.40+0.38syst×1018 year. The two-electron energy sum, single electron energy spectra and distribution of the angle between the electrons are presented with an unprecedented statistics of $$5\times 10^5$$ 5×105 events and a signal-to-background ratio of $$\sim $$ ∼ 80. Clear evidence for the Single State Dominance model is found for this nuclear transition. Limits on Majoron emitting neutrinoless double beta decay modes with spectral indices of $$\mathrm{n}=2,3,7$$ n=2,3,7 , as well as constraints on Lorentz invariance violation and on the bosonic neutrino contribution to the two-neutrino double beta decay mode are obtained.
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