Supplementary Figure 5: Dismantled CaO trap.

a Stainless steel cylinder that can hold 4 kg of CaO with top open. b Inside of a just emptied CaO trap showing the inlet tube going all the way to the bottom. The tube has an outlet for HF at the bottom and small holes in the bottom last third of the tube for a better distribution of HF. c & d The top of the CaO trap displaying the outlet to the vacuum pump as well as the O-ring required for a good seal.