A P Garyaka et al 2008 J. Phys. G: Nucl. Part. Phys. 35 115201 doi:10.1088/0954-3899/35/11/115201
An all-particle primary energy spectrum in the 3–200 PeV energy range
A P Garyaka1, R M Martirosov1, S V Ter-Antonyan2, A D Erlykin3, N M Nikolskaya3, Y A Gallant4, L W Jones5 and J Procureur6
Show affiliationsWe present an all-particle primary cosmic-ray energy spectrum in the 3 × 106–2 × 108 GeV energy range obtained by a multi-parametric event-by-event evaluation of the primary energy. The results are obtained on the basis of an expanded EAS data set detected at mountain level (700 g cm−2) by the GAMMA experiment. The energy evaluation method has been developed using the EAS simulation with the SIBYLL interaction model taking into account the response of GAMMA detectors and reconstruction uncertainties of EAS parameters. Nearly unbiased (<5%) energy estimations regardless of a primary nuclear mass with an accuracy of about 15–10% in the 3 × 106–2 × 108 GeV energy range respectively are attained. An irregularity ('bump') in the spectrum is observed at primary energies of ~7.4 × 107 GeV. This bump exceeds a smooth power-law fit to the data by about 4 standard deviations. By not rejecting the stochastic nature of the bump completely, we examined the systematic uncertainties of our methods and conclude that they cannot be responsible for the observed feature.
- PACS
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96.50.sb Composition, energy spectra and interactions
96.50.sd Extensive air showers
98.70.Sa Cosmic rays (including sources, origin, acceleration, and interactions)
- Subjects
- Dates
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Issue 11 (November 2008)
Received 2 April 2008
Published 12 August 2008
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An all-particle primary energy spectrum in the 3–200 PeV energy range
A P Garyaka et al 2008 J. Phys. G: Nucl. Part. Phys. 35 115201
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