Meteorites as space probes for testing the spatial constancy of cosmic radiation

An experiment has been performed to test the spatial constancy of cosmic radiation within the solar system by measuring a short-lived and long-lived cosmic-ray-induced radioactivity in a recently fallen stone meteorite. The measurement was performed on the Hamlet chondrite that fell in Indiana on October 13, 1959. The ratio of the 35-day argon 37 to the 325-year argon 39 was found to be 2.0±0.3. The relative production rates for these isotopes was determined by bombarding the meteorite with 3-bev protons. The ratio of the argon 37 to argon 39 production rates was found to be 1.5±0.2. Since the ratios were the same within experimental uncertainty, it was concluded that the flux of cosmic radiation is constant in the space between the earth and the asteroidal belt. The argon 39 contents of four other chondrites were measured. The values obtained were as follows: Richardton 7.1±0.6, Murray 9.4±0.5, Forest City 11.9±0.5, Benton 9.0±0.4, and Hamlet 7.8±0.2 dis/min kg.