[en] The neutron capture cross sections of ¹¹⁴Sn, ¹¹⁵Sn, ¹¹⁶Sn, ¹¹⁷Sn, ¹¹⁸Sn, and ¹²⁰Sn were measured in the enrgy range from 3 to 225 keV at the Karlsruhe 3.75 MV Van de Graaff accelerator. Neutrons were produced via the ⁷Li(p, n)⁷Be reaction by bombarding metallic Li targets with a pulsed proton beam. Capture events were registered with the Karlsruhe 4π Barium Fluoride Detector, which was improved by replacing crystals with high α background. This allowed to lower the threshold in sum energy and resulted in a significantly increased efficiency for capture events. The experiment was difficult due to the small (n, γ) cross sections of the proton magic tin isotopes, and due to the comparably low enrichment of the rare isotopes ¹¹⁴Sn and ¹¹⁵Sn. This caused significant corrections for capture of scattered neutrons and for isotopic impurities, but the high efficiency and the spectroscopic quality of the BaF₂ detector allowed to determine these corrections reliably. Typical overall uncertainties of 1-2% could be achieved for the cross section ratios, five times smaller compared to existing data. Based on these results, Maxwellian averaged (n, γ) cross sections were calculated for thermal energies between kT=10 keV and 100 keV. (orig.)