arXiv subjects
Publications and source records attributed to J. Stamenov.
A muon telescope based on 8 water cherenkov detectors was mounted at Basic Environmental Observatory - Moussala - Institute for Nuclear Research and Nuclear Energy - Bulgarian Academy of Science. The telescope will be used for continuous measuring the intensity of the muon component of cosmic rays, exploring its variations and possible correlations with environment parameters. A detailed description of the device is presented in this paper.
The general aim of this work is to obtain the lateral distribution of atmospheric Cherenkov light in extensive air showers produced by different primary particles precisely by. protons, Helium, Iron, Oxygen, Carbon, Nitrogen, Calcium, Silicon and gamma quanta in wide energy range at high mountain observation level of Chacaltaya cosmic ray station. The simulations are divided generally in two energy ranges 10GeV-10 TeV and 10 TeV-10 PeV. One large detector has been used for simulations, the aim being to reduce the statistical fluctuations of the obtained characteristics. The shape of the obtained lateral distributions of Cherenkov light in extensive air showers is discussed and the scientific potential for solution of different problems as well.
The studies realized in INRNE (Institute for Nuclear Research and Nuclear Energy) particulary in cosmic rays detection and construction of Muonic Cerenkov Telescope in University of Blagoevgrad [1] shows the need to develop a theoretical model based on observed phenomenon and to refine it for the detection system optimisation. The effect was introduced in EGS4 code system. The first simulations were consecrated to different geometry of water tank in total reflection. The model was compared with experimental data realised with gamma source using the telescope. A simple atmospheric model is introduced in EGS4. The comparison between CORSIKA and EGS4 codes was realised.
In this paper we present a new method for ground based gamma ray astronomy based only on atmospheric Cherenkov light flux analysis. The Cherenkov light flux densities in extensive air showers (EAS) initiated by different primaries are simulated, precisely primary protons in the energy range 100 GeV – 100 PeV, primary gamma quanta in the energy range 10 GeV – 10 PeV and primary iron nuclei in the energy range 10 TeV –100 PeV using the CORSIKA 6 code at high mountain observation level of 536 g/cm2. An approximation of lateral distribution of Cherenkov light in extensive air showers is obtained. The obtained approximation is a nonlinear fit such as Breit-Wigner with few parameters. A detailed study of the energy dependence of the proposed model function parameters is carried out and the fit of model parameters as a function of the primary energy is obtained as well. On the basis of the difference between the model parameters, precisely their behavior as a function of the energy, the strong no linearity of the model, we propose a method, which permits to make the distinction between gamma ray primaries from hadronic primaries. The possible backgrounds for ground based gamma ray astronomy are studied and the efficiency of the method is calculated. Different detector displacements are analyzed using the simulation of simplified mass spectrum of cosmic ray. The detector response is simulated taking into account the physical fluctuation of the processes, the statistical and possible systematic errors. The simulated and reconstructed events are compared and the accuracy in energy and primary mass reconstruction is obtained. Moreover the accuracy in shower axis determination is studied and criteria in shower axis position estimation are proposed.
The Basic Ecological Observatory (BEO) Moussala is located at 2925m above sea level and one of the main activities is connected with gamma background and neutron dose rate monitoring. The neutron and gamma measurements are carried out with help of site radiation monitor Harwell Type 3208-1. The dose rate of ambient gamma background is measured with SBN-90, improved with the embedded microprocessor system using automatic PC based system. A cross check and inter calibration with existing TLD (thermo luminescent dosimeters) at BEO Moussala which is a part of the monitoring network of INRNE is presented. A polyethylene sphere with a layer of lead serving as a neutron breeder, extending the energy range from about 40 MeV to several hundred MeV is presented as a project in development. Another project in development is the construction of active detector based on SNM-15 detectors for a dose rate measurement of cosmic neutrons is described. Preliminary study of the performances of the detectors are carried out. A further project for muonic telescope similar to the yet developed is discussed.
A new method for energy and mass composition estimation of primary cosmic ray radiation based on atmospheric Cerenkov light flux in extensive air showers (EAS) analysis is proposed. The Cerenkov light flux in EAS initiated by primary protons and iron nuclei is simulated with CORSIKA 5.62 code for Chacaltaya observation level (536 g/cm2) in the energy range 10 TeV - 10 PeV. An adequate model, approximation of lateral distribution of Cerenkov light in showers is obtained. Using the proposed model and solution of overdetermined system of nonlinear equations based on Gauss Newton method with autoregularization, two different array detector arrangements are compared. The detector response for the detector sets is simulated. The accuracies in energy and shower axis determination are studied and the corresponding selection criteria are proposed. An approximation with nonlinear fit is obtained and the energy dependence of the proposed model function parameters is studied. The approximation of model parameters as function of the primary energy is carried out. This permits, taking into account the properties of the proposed method and model, to distinguish proton primaries from iron primaries. The detector response for the detector sets is simulated and the accuracies in energy determination are calculated. Moreover the accuracies in shower axis determination are studied and criteria in shower axis position estimation are proposed.