Experimental test of the anomalous density spectrum of cosmic ray showers, as an adjunct to the South Pole air shower experiment

• Published in: AIP Conference Proceedings (American Institute of Physics); (USA) Vol. 198:1
• Main Author: Hillas, A.M.
• Format: Conference Proceeding
• Language: English
• Published: United States 15.01.1990
• Subjects: 640101 - Astrophysics & Cosmology- Cosmic Radiation; 640201 - Atmospheric Physics- Auroral, Ionospheric, & Magetospheric Phenomena; ANTARCTIC REGIONS; ANTARCTICA; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COSMIC GAMMA SOURCES; COSMIC RADIATION; COSMIC RAY SOURCES; COSMIC SHOWERS; DENSITY; ENERGY RANGE; ENERGY SPECTRA; EXTENSIVE AIR SHOWERS; IONIZING RADIATIONS; MEASURING METHODS; PEV RANGE; PHYSICAL PROPERTIES; POLAR REGIONS; RADIATIONS; SECONDARY COSMIC RADIATION; SHOWERS; SPECTRA
• ISSN: 0094-243X; 1551-7616

Several very simple experiments on air showers, performed 20--25 years ago, gave indications of an unexpected behavor of the shower core. If the particle density on a single small area was recorded, without regard to its position in the shower, its spectrum exhibited a sharp knee, apparently related, though not in a simple way, to the knee in the shower size spectrum. The position of this knee changed rapidly with altitude in a manner which implies that the primary particles have a very short interaction mean free path. To check the correctness of these indications that heavy nuclei may dominate the spectrum here and may generate unexpectedly dense and narrow showers at PeV energies, an experiment is being developed to measure this density spectrum with much better statistics than was done in the early work, at mountain altitudes, under various thicknesses of atmosphere. The location and nature of the SPASE array offers the possibility to test this phenomenon with simple addition to the existing array.