• Key publications:
    • A.P. Garyaka, R.M. Martirosov, S.V. Ter-Antonyan, N. Nikolskaya, Y.A. Gallant, L. Jones, J. Procureur, "Rigidity-dependent cosmic ray energy spectra in the knee region obtained with the GAMMA experiment", Astroparticle Physics 28, 2 (2007) 169,  arXiv: 0704.3200inSPIRE.

    • S.V. Ter-Antonyan, "Mutually compensative pseudo solutions of primary energy spectra in the knee region", Astroparticle Physics 28, 3 (2007) 321 ,  ,  arXiv:0706.4087inSPIRE.

    • A.P. Garyaka, R.M. Martirosov, S.V. Ter-Antonyan, A.D. Erlykin, N. Nikolskaya, Y.A. Gallant, L. Jones, and J. Procureur, "All-particle primary energy spectrum in the 3-200 PeV energy range", Journal of Physics G: Nuclear and Particle Physics, 35 (2008) 115201. IOPSCIENCE,  , arXiv:0808.1421inSPIRE.

    • Romen M. Martirosov, Samvel V. Ter-Antonyan, Anatoly D. Erlykin, Alexandr P. Garyaka, Natalya M. Nikolskaya, Yves A. Gallant and Lawrence W. Jones, "Galactic diffuse gamma-ray flux at the energy about 175 TeV", Proceedings of 31st International Cosmic Ray Conference, Lodz, Poland (2009),   arXiv:0905.3593,  inSPIRE.

    • Anatoly Erlykin, Romen Martirosov and Arnold Wolfendale, "The origin of cosmic rays", CERN Courier,  (2011) 51 (1) p.21.

    • Samvel Ter-Antonyan, "Sharp knee phenomenon of primary cosmic ray energy spectrum", Physical Review D 89, 123003 (2014),  arXiv:1405.5472,  inSPIRE .

  • References to the GAMMA RESULTS
  • GAMMA in WikipediA
  • Selected Presentations:
  • Selected Reports:
    • Primary P, He, O-like, Fe-like nuclei energy spectra in the knee region
    • All-particle primary energy spectrum in 1-200 PeV energy range  
    • Pseudo solutions of cosmic ray inverse problems  
  • Selected Posters: ECRS Kosice (2008), ECRS Lisbon (2006)



    GAMMA experiment is a study of:

    • Galactic diffuse gamma-ray intensity at energies 1014Eγ≲1015eV    ;
    • Primary cosmic-ray energy spectra and elemental composition at energies 1015EA≲1018eV for primary nuclei AH, He, and AO-like, AFe-like nuclei species,       ,    ;
    • Extensive Air Showers (EAS) at the mountain level (700 g/cm² atmosphere depth) by the ground-based scintillation EAS array and underground muon scintillation carpet    ,    ;
    • Hard jet productions at energies E ≳ 1016eV by the muon multi-core EAS events (see Undergr. Muon Hall in Menu).

    GAMMA Array is deployed on the South side of Mount Aragats in Armenia (Cosmic Ray Observatory at the Yerevan Physics Institute, 3200 m above sea level, 700 g/cm²) and was established in 1986 as a part of ANI project in the frameworks of the Yerevan Physics Institute and Moscow Lebedev Physical Institute (Russia) collaboration. The ANI project has a long history of realization of the cosmic ray experiments. Three experiments were ran (PION-EAS, MAKET-ANI and GAMMA) between 1980 and 2003 using novel approach in the investigations of EAS, such as the detection of all (hadron, muon, electron-photon) high energy shower components at the observation level.

    Since 2003, the GAMMA experiment is a stand-alone project in the range of High Energy Astroparticle and Cosmic-Ray Physics. For proposals and comments please visite contact page.

    GAMMA detector: Ground-based EAS array and Biblical Ararat (background)

    The 33 registration stations of EAS array are disposed on the 5 concentric circles (Rmax = 100 m). Each station contains 3 plastic scintillators (1×1×0.05) m³ to detect the energy deposit of EAS charged particles and one fast-timing detector to record a time of the flight of shower front. The zenith angular accuracy is Δθ ≤ 1.5°. EAS core coordinate reconstruction accuracy is less about 1m. The EAS size (Nch) measurement range is about 10⁵-10⁸, which corresponds to 0.5≲E≲200 PeV primary nuclei energies,  . The EAS size measurement errors are ΔNch/Nch ~ 10%.

    GAMMA detector: Underground Muon Hall

    Underground Muon Hall (under ~2500 g/cm² of rock and concrete) includes Computer Center for experiment management, data acquisition, preliminary data processing and muon scintillation carpet  with 150 (200 since 2012) compactly arranged plastic scintillators (1×1×0.05) m³ to detect EAS muon component with energies Eμ (4.5 GeV)/cosθ. The measurement range of truncated (Rμ≤50 m) EAS muon size is 103Nμ≲105. Corresponding muon shower size reconstruction accuracies are ΔNμ / Nμ ~ 30-20%,    .

    Voyage round GAMMA Experiment   

    North Aragats peak.
    Elevation: 13420 ft (4090 m) and 3 mi northward GAMMA experiment

  • Last update: Nov. 20, 2015