A new method was developed for AMS measurement of 126Sn. Major features of the method include the preparation of SnF2 samples, the use of SnF2 as target material, the selection of SnF 3 - molecular ions for the AMS measurements, and the quantitative calibration of our Beijing HI-13 AMS measurements by using samples with 126Sn determined by γ-ray spectrometry. The results indicate that the relative uncertainty of the 126Sn/Sn calibrated by γ-ray spectrometry is better than 4% for samples with 126Sn/Sn of 10−8 to −9. A beam current of 126Sn up to 400 nA can be obtained by the combination of SnF2/ SnF 3 - (target sample, selected ions), while 126Te interference was reduced by 2–3 orders of magnitude. A perfect linearity (R2 = 0.99975) between measured and nominal 126Sn/Sn values was obtained by using three standard samples (diluted from the one calibrated by γ-ray spectrometry) with 126Sn/Sn ratios of 1.033 × 10−8, 4.54 × 10−9, 6.43 × 10−10, respectively. A sensitivity of (1.92 ± 1.13) × 10−10 (126Sn/Sn) has been reached by measuring a blank sample.
