The procedure for Grand Unified Theory (GUT) monopole searches by means of the NT200 Baikal neutrino detector is described. Event-selection and background-suppression algorithms are discussed in ...detail. Limits on the flux of slow monopoles are presented and are compared with theoretical predictions and with the results of other experiments.
We consider issues related to the determination of integral characteristics of the scattering phase function for media with a highly forward directed scattering function. We show that, as a rule, the ...standard method of calculation of the average cosine of the scattering angle does not take into account the contribution that is important for scattering in the direction of small angles. We present a technique that makes it possible to obtain necessary corrections for the integral scattering characteristics in this case.
An approach allowing one to calculate the spatiotemporal intensity distribution of light from a point source with the use of integral scattering characteristics is considered. Using this approach in ...practice has an undeniable advantage because it does not require knowing the scattering function for the whole range of angles, in particular, in the region of small angles where the measurement of the scattering phase function for media with predominantly forward scattering involves considerable experimental difficulties.
We reanalyze the dataset collected during the years 1998–2003 by the deep underwater neutrino telescope NT200 in the lake Baikal with the low energy threshold (10 GeV) in searches for neutrino signal ...from dark matter annihilations near the center of the Milky Way. Two different approaches are used in the present analysis: counting events in the cones around the direction towards the Galactic Center and the maximum likelihood method. We assume that the dark matter particles annihilate dominantly over one of the annihilation channels bb¯,W+W−,τ+τ−,μ+μ− or νν¯. No significant excess of events towards the Galactic Center over expected neutrino background of atmospheric origin is found and we derive 90% CL upper limits on the annihilation cross section of dark matter.
We have analyzed a data set taken over 2.76years live time with the Baikal neutrino telescope NT200. The goal of the analysis is to search for neutrinos from dark matter annihilation in the center of ...the Sun. Apart from the conventional annihilation channels bb¯, W+W- and τ+τ- we consider also the annihilation of dark matter particles into monochromatic neutrinos. From the absence of any excess of events from the direction of the Sun over the expected background, we derive 90% upper limits on the fluxes of muons and muon neutrinos from the Sun, as well as on the elastic cross sections of dark matter scattering on protons.
Current status of the BAIKAL-GVD project Avrorin, A.V.; Aynutdinov, V.M.; Belolaptikov, I.A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2013, Letnik:
725
Journal Article
Recenzirano
We present a status of the Baikal-GVD Project. The objective of this project is a construction of a km3-scale neutrino telescope in the Lake Baikal. As an important milestone, the first GVD ...engineering array has been deployed and ran in April, 2011. Application of a completely new technology gave us an opportunity to study all the basic elements of the future full detector and to finalize the GVD technical design. We discuss the configuration and the design of the engineering array as well as data performance with the preliminary results.
The first stage of the GVD-cluster composed of five strings was deployed in April 2014. Each string consists of two sections with 12 optical modules per section. A section is the basic detection unit ...of the Baikal neutrino telescope. We will describe the section design, review its basic elements – optical modules, FADC readout units, slow control and calibration systems, and present selected results for section in-situ tests in Lake Baikal.
We analyze sensitivity of the gigaton volume telescope Baikal-GVD for detection of neutrino signal from dark matter annihilations or decays in the Galactic Center. Expected bounds on dark matter ...annihilation cross section and its lifetime are found for several annihilation/decay channels.
The Prototyping phase of the BAIKAL-GVD project has been started in April 2011 with the deployment of first autonomous engineering array which comprises all basic elements and systems of the Gigaton ...Volume Detector (GVD) in Lake Baikal. The prototyping phase will be concluded with deployment of the GVD demonstration cluster “DUBNA” in 2015, which will comprise 192 light sensors arranged at 8 strings. The first stage of the GVD demonstration cluster which consists of three strings was deployed in April 2013 and successfully operated up to February 2014. We review the prototyping phase of the BAIKAL-GVD project and describe the configuration and design of the 2013 engineering array.
We have studied the enhancement of luminescence of (CdSe)ZnS core−shell quantum dots on gold colloids as a function of semiconductor nanocrystal−metal nanoparticle distance. Using a layer-by-layer ...polyelectrolyte deposition technique to insert well-defined spacer layers between gold colloids and quantum dots, a distance-dependent enhancement and quenching of quantum dot photoluminescence has been observed. The maximum enhancement by a factor of 5 is achieved for a 9-layer spacer (≈11 nm). The efficient quantum dot excitation within the locally enhanced electromagnetic field produced by the gold nanoparticles is evidenced by the observation of the surface plasmon resonance in the photoluminescence excitation spectrum of (CdSe)ZnS nanocrystals.
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