• 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 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 run (PION-EAS, MAKET-ANI and GAMMA) between 1980 and 2003 using novel approach in the study of EAS - the detection of all high energy shower components at the observation level such as the shower hadrons (Eh≳1 TeV), muons (Eμ≳4-5 GeV) and electron-photons (Ech≳6-8 MeV).

    Since 2003, the GAMMA experiment is a stand-alone project in the realm 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

    The underground Muon Hall (under ~2500 g/cm² of rock and concrete) includes the 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: Dec. 9, 2015