Intercalibration

For small volume mass spectrometric tritium measurement an intercalibration with the Heidelberg low-level β-counting laboratory was done. For this purpose samples taken on a station in the Arctic Ocean were measured both mass spectrometrically and using the low-level counting technique. The accuracy of the βcounting results is ±5% with a detection limit (1 σ) of about 0.08 TU (Weiss et al., 1976). From the result (Fig. 22) it is evident that the errors of the mass spectrometric measurements are smaller than those of the β-counting results, and that within the errors the data show a good agreement. The slope of the fit curve (0.998 ±0.014) is not significantly different from 1, and no significant offset at zero intercept (0.019±0.023 TU) can be observed. This is evidence that within the accuracies of the single measurement techniques the two data sets are in full agreement.