Measurement of the cosmic ray composition at the knee with the SPASE-2/AMANDA-B10 detectors

J. Ahrens, M. Ackermann, E. Andres, X. Bai, S. W. Barwick, R. C. Bay, T. Becka, K. H. Becker, E. Bernardini, D. Bertrand, F. Binon, A. Biron, D. J. Boersma, S. Böser, O. Botner, A. Bouchta, O. Bouhali, T. Burgess, S. Carius, T. CastermansD. Chirkin, J. Conrad, J. Cooley, D. F. Cowen, A. Davour, C. de Clercq, T. DeYoung, P. Desiati, J. P. Dewulf, E. Dickinson, P. Ekström, R. Engel, P. Evenson, T. Feser, T. K. Gaisser, R. Ganugapati, M. Gaug, H. Geenen, L. Gerhardt, A. Goldschmidt, A. Hallgren, F. Halzen, K. Hanson, R. Hardtke, T. Hauschildt, M. Hellwig, P. Herquet, G. C. Hill, J. A. Hinton, D. Hubert, B. Hughey, P. O. Hulth, K. Hultqvist, S. Hundertmark, J. Jacobsen, A. Karle, J. Kim, L. Köpke, M. Kowalski, K. Kuehn, J. I. Lamoureux, H. Leich, M. Leuthold, P. Lindahl, I. Liubarsky, J. Lloyd-Evans, J. Madsen, K. Mandli, P. Marciniewski, H. S. Matis, C. P. McParland, T. Messarius, T. C. Miller, Y. Minaeva, P. Miočinović, P. C. Mock, R. Morse, R. Nahnhauer, T. Neunhöffer, P. Niessen, D. R. Nygren, H. Ögelman, P. Olbrechts, C. Pérez de los Heros, A. C. Pohl, R. Porrata, P. B. Price, G. T. Przybylski, K. Rawlins, E. Resconi, W. Rhode, M. Ribordy, S. Richter, K. Rochester, J. Rodríguez Martino, D. Ross, H. G. Sander, T. Schmidt, K. Schinarakis, S. Schlenstedt, D. Schneider, R. Schwarz, A. Silvestri, M. Solarz, G. M. Spiczak, C. Spiering, M. Stamatikos, T. Stanev, D. Steele, P. Steffen, R. G. Stokstad, K. H. Sulanke, I. Taboada, S. Tilav, C. Walck, W. Wagner, Y. R. Wang, A. A. Watson, C. H. Wiebusch, C. Wiedemann, R. Wischnewski, H. Wissing, K. Woschnagg, W. Wu, G. Yodh, S. Young

Research output: Contribution to journalArticle

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The mass composition of high-energy cosmic rays at energies above 1015 eV can provide crucial information for the understanding of their origin. Air showers were measured simultaneously with the SPASE-2 air shower array and the AMANDA-B10 Cherenkov telescope at the South Pole. This combination has the advantage to sample almost all high-energy shower muons and is thus a new approach to the determination of the cosmic ray composition. The change in the cosmic ray mass composition was measured versus existing data from direct measurements at low energies. Our data show an increase of the mean log atomic mass 〈lnA〉 by about 0.8 between 500 TeV and 5 PeV. This trend of an increasing mass through the "knee" region is robust against a variety of systematic effects.

Original languageEnglish
Pages (from-to)565-581
Number of pages17
JournalAstroparticle Physics
Issue number6
Publication statusPublished - 1 Sep 2004
Externally publishedYes



  • Cosmic Rays
  • Mass composition
  • Neutrino astronomy

ASJC Scopus subject areas

  • Astronomy and Astrophysics

Cite this

Ahrens, J., Ackermann, M., Andres, E., Bai, X., Barwick, S. W., Bay, R. C., Becka, T., Becker, K. H., Bernardini, E., Bertrand, D., Binon, F., Biron, A., Boersma, D. J., Böser, S., Botner, O., Bouchta, A., Bouhali, O., Burgess, T., Carius, S., ... Young, S. (2004). Measurement of the cosmic ray composition at the knee with the SPASE-2/AMANDA-B10 detectors. Astroparticle Physics, 21(6), 565-581.