28 Cruise Report, RV ATAIR, Cruise 067I033-1, Bremerhaven – Thybor?n – Aberdeen, 23 Jul – 15 Aug 2024 samples were shipped home for later laboratory analysis. First, the water samples were de- gassed using a high-vacuum gas extraction system and subsequently stored in flame-sealed glass containers to accumulate 3He from tritium decay, using the so-called helium ingrowth method. During storage over several months, some of the ?H decays to ?He via ?-decay. After sufficient ?He production, the water samples are connected to a fully automated ultra-high vac- uum system and reopened. Water vapour is then used to transfer the ?He to a cryo-system kept at 14 K to separate ?He from any other possible gases. A high-resolution rare gas mass spectrometer (MAP 215-50) is then used to analyse the 3He. The system is regularly calibrated using atmospheric air standards (the precision for tritium is 3% or 0.02 TU, where TU stands for tritium units). Measurements of blanks and linearity are also performed. Further details of the method can be found in Sültenfuß et al. (2009). Figure 5.11. Distribution of stations carried out during cruise 067I033-1 with tritium sampling (red dots).