Solar proton events in cosmogenic isotope data

A possible contribution of solar energetic particle events to the production of cosmogenic Be-10 and C-14 in the atmosphere is studied. The solar particle effect is negligible in the C-14 data, but extreme events may be detectable in high-resolution C-14 data. Although the overall effect is small in the Be-10 data, strong events may contribute notably on the inter-annual time scale. In combination with the 11-year solar modulation of galactic cosmic rays, it may lead to an intermittent 5.5-year periodicity, which is seen in high resolution Be-10 data. We have identified ten episodes during 1750-1950 when Be-10 may hold signatures of strong solar proton events. This opens a new possibility to study extreme solar particle events in the past using high resolution cosmogenic isotope data.