Absorption Mean Free Path of the Nucleonic Component of Cosmic Radiation

Abstract

The absorption mean free path $L$ of star-producing radiation was determined by means of the local production of neutrons in condensed materials; for that purpose a neutron monitor was installed in an aircraft, and two flights were performed at the geomagnetic latitudes 23.3°S (Buenos Aires, República Argentina) and 15°S (Asunción, República del Paraguay). The results show an increase in $L$ of about 20% for an altitude increase of 6000 m in Buenos Aires, and of 40% in Asunción, for the same altitude increase; the total $L$ value in Asunción was found to be 175 g ${\mathrm{cm}}^{-2\mathrm{}}$, while in Buenos Aires it was 163 g ${\mathrm{cm}}^{-2\mathrm{}}$, that is, approximately 8% lower.