IN SITU PRODUCED 10BE MEASUREMENTS AT GREAT DEPTHS: IMPLICATIONS FOR PRODUCTION RATES BY FAST MUONS

Abstract

In situ cosmogenic 10Be values have been used to investigate a Brazilian quartz vein from the surface to a depth of 15 m. At depths greater than 1000 g/cm2, deep enough for neutron-induced reactions to be insignificant, there is only a slight decrease in 10Be concentration with increasing depth. Our results are consistent with deep production of 10Be by a mechanism, presumably induced by fast muons, with an attenuation length of 5300+/-950 g/cm2 and a contribution of 0.65+/-0.25% to the total surface production. Results are compared with values from the literature and implications of this re-evaluation are discussed.