Secondly, the selected area is isolated using the energetic gallium ion beam. Once the area is isolated, the milling process begins using a high current ion beam, and then the ion beam current is reduced as the lamella becomes thin (down to 0.8-1 mm). The lamella is then removed from the substrate with a micro-manipulator and transferred to a TEM sample grid. A second milling process using very low ion beam currents, is performed to thin the lamella until its thickness is about 150-200 nm. The lamella obtained is then removed from the FIB and put under a controlled atmosphere into a transfer coffer in order to avoid air exposure during sample handling. These samples were then transferred in a sealed box to the STXM chamber for measurements.