ACCELERATOR MEASUREMENTS OF BE-10 - THE 11 YEAR SOLAR-CYCLE FROM 1180-1800 AD

In order to investigate the extent to which **1**0Be concentrations in polar ice record solar activity on the level of individual Schwabe solar cycles, **1**0Be concentrations have been measured over the interval from 1180 to 1800 A. D. in an ice core from Greenland, using the accelerator mass spectrometer of the ETH Zurich. The data were analyzed using the cyclogram method of time series analysis which showed that **1**0Be concentrations varied with a period which ranged between 9 and 11. 4 y. **1**0Be concentrations were higher during the Maunder Minimum than during minima in the 11 y Schwabe cycle. This suggests the presence of residual solar modulation even during Schwabe solar cycle minima.