We present the results of a search for high-energy extraterrestrial neutrinos with the Baikal underwater Cherenkov detector NT200, based on data taken in 1998–2003. Upper limits on the diffuse fluxes ...of
ν
e
+
ν
μ
+
ν
τ
, predicted by several models of AGN-like neutrino sources, are derived. For an
E
−2 behavior of the neutrino spectrum, our limit is
E
2
Φ
ν
(
E)
<
8.1
×
10
−7
cm
−2
s
−1
sr
−1
GeV over an neutrino energy range 2
×
10
4–5
×
10
7
GeV. The upper limit on the resonant
ν
¯
e
diffuse flux is
Φ
ν
¯
e
<
3.3
×
10
-
20
cm
-
2
s
-
1
sr
-
1
GeV
-
1
.
A multipurpose deep-water experimental string has been developed for testing new promising techniques and performing methodical tasks of deep-water muon and neutrino detection in Lake Baikal. The ...design of the setup is described, and some experimental results obtained with the pilot sample of the string under field conditions on Lake Baikal are presented.
Measurements of group velocity of light in the lake Baikal water Lubsandorzhiev, B.K.; Pokhil, P.G.; Vasiliev, R.V. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2003, Letnik:
502, Številka:
1
Journal Article
Recenzirano
The results of direct measurements of group velocity of light in the lake Baikal water at the depth of 1100m are presented. The lake Baikal water dispersion has been measured at three wavelengths: ...370, 470 and 525nm. The results are in a rather good agreement with theoretical predictions.
A system for calibrating the external strings located at a distance of ∼100 m from the core of the NT-200+ deep-water neutrino telescope on Lake Baikal is described. The calibration system is ...composed of nanosecond light pulsers based on ultrabright blue LEDs. It is shown that the accuracy in synchronizing the external strings with the central part of the telescope, attained using this system, is 1 ns or better.
Powerful nanosecond light sources based on LEDs have been developed for use in calibration systems of deep underwater neutrino telescopes. The light sources use either matrixes of ultra bright blue ...InGaN LEDs or new generation high power blue LEDs. It is shown that such light sources have light yield of up to 10
10–10
12 photons per pulse with very fast light emission kinetics. The developed light sources are currently used in a number of astroparticle physics experiments, namely: the lake Baikal neutrino experiment, the TUNKA EAS experiment, etc.
Photoelectron backscattering in vacuum phototubes Lubsandorzhiev, B.K.; Vasiliev, R.V.; Vyatchin, Y.E. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2006, Letnik:
567, Številka:
1
Journal Article
Recenzirano
Odprti dostop
In this article we describe results of studies of a photoelectron backscattering effect in vacuum phototubes: classical photomultipliers (PMT) and hybrid phototubes (PH). Late pulses occurring in ...PMTs are attributed to the photoelectron backscattering and distinguished from pulses due to an anode glow effect. The late pulses are measured in a number of PMTs and HPs with various photocathode sizes covering 1–50
cm range and different types of the first dynode materials and construction designs. It is shown that the late pulses are a generic feature of all vacuum photodetectors—PMTs and PHs—and they do not deteriorate dramatically amplitude and timing responses of vacuum phototubes.
The kinetics of scintillation process in Czochralski-grown CaMoO
4
crystals excited by α particles and γ rays from
238
Pu and
137
Cs radioactive isotopes, respectively, is investigated. Kinetics of ...scintillations is shown to be complex and multicomponent in character. Fast and slow scintillation components are observed, and their relative contributions to the total light yield in the scintillator are determined. The possibility is demonstrated of discriminating between scintillator signals due to α particles and γ rays.
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