Abstract
The nucleosynthetic origin of ( Myr) in the early solar system is still an open question. Several models predict that short-lived radionuclides could be produced by irradiation of circumsolar material by light charged particles emitted by the young sun. Within some models, most of the is produced by -induced reactions on . Little experimental data exist on reactions so that irradiation models have had to rely on theoretical cross sections deduced from statistical nuclear reaction codes. We performed a direct measurement of the production on Mg target by means of ray spectroscopy and accelerator mass spectrometry (AMS). The data indicate that the theoretical cross section used in previous approaches was overestimated by a factor of 3. Taking the particle spectra considered in theoretical approaches these data lead to a net reduction of the production of a factor of 2. We calculated the relative contribution of the different production channels depending on the irradiation scenario. We show that extremely large particles fluxes would be necessary to reach the canonical in solids that were present in the early solar system. An in situ origin of this important isotopic chronometer by irradiation is unlikely.
5 More- Received 22 June 2008
DOI:https://doi.org/10.1103/PhysRevC.78.044613
©2008 American Physical Society