Search for 59Ni of extraterrestrial origin in deep sea sediments

Abstract Ni-59 was measured with an extremely low background X-ray spectrometer in 0.5 g of nickel which was isolated chemically from deep sea sediments. The obtained specific activity of Ni-59 in the sediments was (0.26 ± 0.14) dpm/g Ni. However, the Ni-59 activity induced by proton and alpha particle irradiation in outer space with a few assumptions can be estimated as 13.0 dpm/g Ni in cosmic dusts. The maximum contribution of extraterrestrial nickel to the nickel component in deep sea sediments is ∼2%.