Cosmic ray produced beryllium isotopes in rain water

Abstract

The two known radioactive isotopes of Beryllium (Be⁷ and Be¹⁰) are produced in the atmosphere in nuclear disintegrations initiated by cosmic radiation. The long lived Be¹⁰ (half life 2.7 million years) is difficult to detect and has not yet been isolated. The short lived isotope Be⁷ (half life 53 days) is easily detected in rain water and should, therefore, be of interest in meteorological studies. The average concentration of Be⁷ in 8 monsoon rains in Bombay amounted to 2400 atoms per cm³ and is consistent with the production rates predicted by Paters).