a. chilingarian yerevan physics institute, yerevan, armenia,

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Operation of the Space Environmental viewing and Analysis Network (Sevan) in 24-th Solar Activity Cycle. A. Chilingarian Yerevan Physics Institute, Yerevan, Armenia, Alikhanyan Brothers 2, Yerevan 375036, Armenia,. Design of the SEVAN basic unit. - PowerPoint PPT Presentation


  • A. ChilingarianYerevan Physics Institute, Yerevan, Armenia, Alikhanyan Brothers 2, Yerevan 375036, Armenia,

  • 100 traversal of the low energy charged particle (250, 200MeV);

  • Starting of SEVANs in Bulgaria and Croatia

  • Modulation of Galactic Cosmic Rays

  • Selection of Secondary Cosmic Rays

  • Purity-Efficiency Diagram

  • SEVAN Count Rates

    Aragats3200 a.s.l.ArNM18NM64SEVAN[100]SEVAN [010]SEVAN [111]Relative Error0.00680.00810.02180.01921/sqrt(N)0.00490.00780.02230.0194

    YerPhI (1200m)NorAmberd (2000m)Aragats (3200m)Zagreb, Croatia(130m)Moussala, Bulgaria, (2925 m)Type of secondary particleMeasuredcount rateSimulatedcount rateMeasuredcount rateSimul. Measuredcount rateSimulatedcount rateMeasuredCount rateMeasuredcount rateLow energy charged particles(100)886210872021159316110220165811301720264158417479136Neutral particles(010)3631935969027795201146158431618111538High energy muon(111 & 101)433767547744739955485534648051382464631578

  • Barometric coefficients, count rates and relative errors of SEVAN monitors

    MonitorAltitude(m)Rc(Gv)BarometricCoeff. %/mbCorrelationCoefficientCount rate [min]Relative errorAragats SEVAN Low energy charged particles (Coincidence 100)32007.1-0.50.0180.995153890.0070.0080Aragats SEVAN High energy muons(Coincidence 111+ Coincidence 101)32007.1-0.3510.0380.9638680.0140.0161Aragats SEVAN neutrons(Coincidence 010)32007.1-0.5110.0180.99519590.0190.0225Nor Amberd SEVAN Low energy charged particles (Coincidence 100)20007.1-0.2810.0220.95759410.0130.0129Nor Amberd SEVANHigh energy muons(Coincidence 111+ Coincidence 101)20007.1-0.2420.0220.95219880.0260.0224Nor Amberd SEVAN neutrons (Coincidence 010)20007.1-0.540.0700.8996740.0370.0385Yerevan SEVAN Low energy charged particles (Coincidence 100)10007.1-0.30.0140.98794460.0100.0102 SEVAN High energy muons(Coincidence 111+ Coincidence 101)10007.1-0.1490.0350.76547140.0150.0145Yerevan SEVAN neutrons(Coincidence 010)10007.1-0.40.0390.9434250.0480.0485

  • 5min simulated enhancements in the Upper and Middle layers of the SEVAN basic unit.

    Detector LayerSolar ProtonsSolar NeutronsUpper 5cm scintillator4.82.6Middle 25 cm scintillator1.76.4

  • Space Weather alerts: SEVAN can estimate on-line Spectral knees of Solar CR

  • High Solar Activity in March 2012

  • March 2012 Fd: on-line data from all SEVANs and all NMs in: http://adei.crd.yerphi.am/

  • SEVAN calibration with gamma rays from Thunderstorm Ground Enhancements (TGEs): Electrons born gamma rays and gamma rays neutrons.

  • Deficit of high energy muons- positive muons stop: evidence of large potential drop in thundercloud~5% deficit in muon flux prove existence of large potential drop in thundercloud accelerated electrons in the direction to Earth surface

  • SEVAN Advantages The hybrid particle detectors, measuring neutral and charged fluxes provide following advantages upon existing detector networks measuring single species of secondary CR:Cheap and simple operation; Probe different populations of primary cosmic rays with rigidities from few GV (neutrons) up to 20-30 GV (muons);Reconstruct SCR spectra and determine position of the spectral knees;Classify GLEs in neutron or proton initiated events;Significantly enlarge the reliability of Space Weather alerts due to detection of 3 particle fluxes instead of only one in existing neutron monitor and muon telescope world-wide networks.Detect Thunderstorm Ground Enhancements both electron and gamma ray fluxes



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