English: The AD 774/5 event in view of 10Be, 14C and 36Cl. Time series for AD 760–810 (a) of 10Be flux from the NEEM-2011-S1, NGRIP and WDC ice cores in addition to the inferred average 10Be flux (thick blue curve), (b) of modelled 14C production rate based on previously published measurements12 and (c) of 36Cl flux21 in addition to an inset with a longer series spanning AD 500–1500 for 36Cl where the grey rectangle represents the time slice investigated. The dashed lines represent the natural background levels which are set as the average values prior to and following the filled areas. The filled areas represent the estimated production enhancements caused by the cosmic-ray event of AD 774/5. The 10Be and 36Cl series have been corrected for a temporal offset between ice-core and tree-ring chronologies (Methods). The right panel shows radionuclide production enhancements caused by the AD 774/5 event in atoms cm−2 s−1 for 1 year for (d) 10Be, (e) 14C and (f) 36Cl. The radionuclide increases are illustrated with arrows corresponding to the ratio between the inferred flux/production enhancements stacked over 1 year (coloured rectangles) and the estimated background levels (white rectangles). Uncertainties are based on error propagation including measurement errors and a background variability of 1σ.