R. V. Novoseltseva

The search for neutrino bursts from core collapse Supernovae at the Baksan Underground Scintillation Telescope

The current status of the experiment on recording neutrino bursts from core collapse stars is presented. The actual observational time T (from June 30, 1980 until December 31, 2009) is 25.58 years. An upper bound of the mean frequency of gravitational collapse in our Galaxy fcol < 0.090 year−1 at a 90% confidence level. The results of studying single events at the facility in the case of muon inelastic interaction of cosmic rays with the matter of the detector are presented.

The search for neutrino bursts from supernovae with Baksan underground scintillation telescope

The current status of the experiment on recording neutrino bursts from core collapse stars is presented. The actual observational time is 29.76 years. An upper bound of the mean frequency of core collapse supernovae in our Galaxy is fcol < 0.077 year–1 (90% CL).

Detection of muon groups with multiplicity nμ > 1500 at the Baksan underground scintillation telescope

Abstract A method of detection of muon groups with multiplicity n μ ( E μ ⩾ 220 GeV) > 1500 is presented. Such events give information about the flux of primary nuclei with energy E N > 10 16 eV. The systematic errors of the method have been studied. The error in determining n μ is ⩾ 15%. Data from detection of muon groups with n μ ( E μ ⩾ 220 GeV) > 1500 obtained over exposure time T = 35410 h are presented.

Observation of “the knee” in cosmic ray energy spectrum with underground muons and primary mass composition in the range 1015–1017 eV

Abstract The method of recalculation from the muon multiplicity spectrum to the extensive air showers spectrum vs the total muon number, nμ, is presented. The method allows the direct comparison of data obtained in different experiments with muon groups. The direct comparison of the data at nμ > 1800 and nμ = 75–660 has been carried out. The data in the region nμ = 75–3500 agree better with the assumption that the slope change in the energy spectrum of primary cosmic rays occurs at the same energy per nucleus E c ⋍ 3 · 10 15 eV and the mass composition in energy range 1015–1017 eV is close to the one observed at 1014 eV.

Neutron flux measurement using activated radioactive isotopes at the Baksan underground scintillation telescope

Preliminary results of a neutron background measurement at the Baksan underground scintillation telescope (BUST) are presented. The external planes of the BUST are fully covered with standard scintillation detectors shielding the internal planes and suppressing thus background events due to cosmogenic and local radioactivity. The shielded internal planes were used as target for the neutron flux registration. The experimental method is based on the delayed coincidences between signals from any of the BUST counters. It is assumed that the first signal is due to inelastic interaction of a neutron with the organic scintillator, while the second signal comes from the decay of an unstable radioactive isotope formed when the fast neutron interacts with the 12C nuclei. Using the Monte-Carlo method (GEANT4) we also simulated propagation of neutrons through a layer of scintillator. The experimentally found muon induced neutron flux is j =1.3 -0.3 +0.7 ×10-10cm-2s-1 for neutron energies E ≥ 22MeV, which is in a qualitative agreement with similar measurements of other underground laboratories as well as with predictions of the GEANT4.

Total cross section for photon-nucleon interaction in the energy range \(\sqrt \mathcal{S} = 40 - 250 GeV\)

AbstractResults obtained by directly measuring the total cross section for photon-nucleon interaction through recording photoproduction processes at the Baksan underground scintillation telescope of the Institute for Nuclear Research (Russian Academy of Sciences, Moscow) are presented. The effect of a faster growth of photon-hadron cross sections in relation to hadron-hadron cross sections is confirmed in the energy range

The search for high energy muon neutrinos from southern hemisphere gamma-ray bursts with BUST

\sqrt \mathcal{S} = 40 - 130 GeV

Temperature effects in high-energy muon fluxes and the problem of reconstructing the atmospheric temperature profile

. It is shown that an increase in the number of additive quarks in photon-hadronization products may be one of the reasons behind this effect. Experimental data on the cross sections for photon-nucleon and photon-photon interactions are subjected to a comparative analysis, and the status of the results obtained from direct and indirect cross-section measurements in the high-energy region is discussed.