1. Observation of the ankle and evidence for a high-energy break in the cosmic ray spectrum
- Author
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S. Y. Ben Zvi, Gordon Thomson, J. A.J. Matthews, J. Findlay, John Belz, Steve Schnetzer, B. C. Connolly, L. J. Marek, Michael H. Holzscheiter, C. Song, J. R. Thomas, John N. Matthews, P. Hüntemeyer, M. A. Kirn, C. B. Finley, Lawrence Wiencke, K. M. Simpson, Kevin Reil, William Hanlon, Rasha Abbasi, R. Riehle, B. T. Stokes, W. Deng, N. Manago, Bruce R. Dawson, M. Sasaki, M. D. Roberts, C. M. Hoffman, G. Sinnis, Jose A. Bellido, G. Archbold, Douglas Bergman, C. A. Painter, Z. Cao, A. O’Neill, Konstantin Belov, R. W. Atkins, E.G. Loh, Dale Tupa, R. W. Springer, C. C. H. Jui, G. W. Burt, S. B. Thomas, J. D. Smith, J. F. Amman, R. Snow, L. Perera, S. Westerhoff, K. Kim, Pierre Sokolsky, K. Martens, A. Zech, Gareth Hughes, Tareq Abu-Zayyad, Y. Fedorova, Roger W Clay, and M. M. Maestas
- Subjects
Physics ,Nuclear and High Energy Physics ,Photomultiplier ,Physics::Instrumentation and Detectors ,010308 nuclear & particles physics ,Astrophysics::High Energy Astrophysical Phenomena ,Spectrum (functional analysis) ,Detector ,High resolution ,Cosmic ray ,Astrophysics ,01 natural sciences ,medicine.anatomical_structure ,Computer Science::Systems and Control ,0103 physical sciences ,Calibration ,medicine ,Ankle ,010303 astronomy & astrophysics ,Energy (signal processing) - Abstract
We have measured the cosmic ray spectrum at energies above $10^{17}$ eV using the two air fluorescence detectors of the High Resolution Fly's Eye experiment operating in monocular mode. We describe the detector, PMT and atmospheric calibrations, and the analysis techniques for the two detectors. We fit the spectrum to models describing galactic and extragalactic sources. Our measured spectrum gives an observation of a feature known as the ``ankle'' near $3\times 10^{18}$ eV, and strong evidence for a suppression near $6\times 10^{19}$ eV., Comment: 14 pages, 9 figures. To appear in Physics Letters B. Accepted version
- Published
- 2005