WP2 “LIBS development” focused on the design and analysis of the LIBS system in order to be ready for manufacturing and large-scale testing. Furthermore, the main pressure housing of the LIBS system which will integrate all the main components was designed. Its structure was analyzed for primary hydrostatic and cyclic loads with the Finite Element Method (FEM). In order for the LIBS system to work in 6000 m water depth, all the connections and requisites was studied and assessed and final guidelines and drawings was accomplished. 


Figure 1: Stress and displacement distributions of pressure housing parts (Figure: ALS)

The chemical concentration and composition of Atlantic manganese nodules, Pacific manganese nodules and Massive sulphide has been analysed by using EDX measurements. Based on these results LIBS measurements have been performed under atmospheric conditions to study and identify relevant emission lines. The spectra have been compared with reference spectra. For example, the emission line at 481 nm allows the detection of zinc.

Figure 2: Comparison between massive sulphide and reference samples (Figure: LZH)

To carry out LIBS experiments under the conditions of 6000 m water depth, a 650 bar pressure chamber has been designed and constructed. The pressure chamber allows realistic experiments with a water pressure of up to 650 bar and salinity of <40 PSU without using a ROV or an AUV. 

Figure 3: Pressure chamber for LIBS experiments (Figure: LZH)