Calibration method for ESR signal intensity of calcitic shells

A practical method of calibrating intensities of ESR signals with a single crystal of copper pentahydrate (CuSO4. 5H(2)O) has been developed for calci tic shells containing a large amount of manganese (Mn2+). A sample holder i s designed to insert the crystal from the bottom of the cavity for use as a standard sample. The signal of Cu2+ in the standard does not interfere wit h the Mn2+ signals. The Cu2+ signal and dating signal of the shell are reco rded simultaneously: the ratio of their intensities is the basis for calibr ation. It is shown that this calibration method reduces the errors attribut ed to both coupling and unloaded Q factors of the cavity resonator to withi n 2%.