Measurement of the depth of maximum of extensive air showers above 10.sup.18./sup. eV

0355260 - FZÚ 2011 RIV US eng J - Journal Article
Abraham, J. - Abreu, P. - Aglietta, M. - Boháčová, Martina - Chudoba, Jiří - Kárová, Tatiana - Mandát, Dušan - Nečesal, Petr - Nožka, Libor - Nyklíček, Michal - Palatka, Miroslav - Pech, Miroslav - Prouza, Michael - Řídký, Jan - Schovancová, Jaroslava - Schovánek, Petr - Šmída, Radomír - Trávníček, Petr
Measurement of the depth of maximum of extensive air showers above 10¹⁸ eV.
Physical Review Letters. Roč. 104, č. 9 (2010), 091101/1-091101/7. ISSN 0031-9007. E-ISSN 1079-7114
R&D Projects: GA MŠMT LC527; GA MŠMT(CZ) 1M06002; GA AV ČR KJB100100904; GA AV ČR KJB300100801; GA MŠMT(CZ) LA08016
Institutional research plan: CEZ:AV0Z10100502; CEZ:AV0Z10100522
Keywords : composition * cosmic rays * Pierre Auger Observatory
Subject RIV: BF - Elementary Particles and High Energy Physics
Impact factor: 7.621, year: 2010

We describe the measurement of the depth of maximum, Xmax, of the longitudinal development of air showers induced by cosmic rays. Almost four thousand events above 1018 eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106+35-21) g/cm2/decade below 1018.24+/-0.05 eV and (24 +/- 3) g/cm2/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm2. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.
Permanent Link: http://hdl.handle.net/11104/0194073