Study of Cosmic Ray Produced Short-Lived P³², P³³, Be⁷, and S³⁵in Tropical Latitudes

Abstract

ABS>The fall-out rate of the four short-lived isotopes P/sup 32/, ons of cosmic ray particles with air nuclei, is measured at a number of stations in India and compared with the calculated rate of production. In the case of Be/sup 7/, the agreement between the calculated and measured values is good. The fall- out rates of P/sup 32/ and P/sup 33/ are not inconsistent with the calculated values; that of S35, however, is about five times higher than expected. The absolute concentrations of an individual isotope in various rainfalls are found to vary by more than a factor of forty; relative concentrations of the different isotopes, however, stay within fairly narrow limits. The ratio of the concentration of Be/sup 7/ to that of P/sup 32/ in individual rain samples is used to determine the periods for which various air masses are irradiated in the interval between two successive precipitations. The mean period of irradiation is found to be about thirty-five days. The results are consistent with the view that, in these tropical latitudes~ intrusions of stratospheric air into the troposphere are either rare or weak in intensity. (auth)