Locating mineral resources on the seabed has so far been associated with very high costs. The Laser Zentrum Hannover e.V. (LZH), together with eight other partners in the EU project ROBUST, has developed a laser-based analysis system to examine soil samples in the deep sea almost non-destructively. The system has already passed its first practical tests.
The system for laser-induced breakdown spectroscopy (LIBS) makes it possible to examine material samples almost non-destructively for their atomic composition. The LIBS system developed by the LZH successfully withstood a pressure of 400 bar during practical tests in the deep sea. The laser, control system and software functioned perfectly. At up to 500 bar, the LIBS system was able to detect copper and zinc in real massive sulphide samples. The measurements under deep-sea conditions took place at the company Nautilus in Buxtehude. During a research cruise in the Baltic Sea on GEOMAR's research vessel Littorina, the system was able to reliably detect copper and zinc in the prepared samples, even in relatively turbid water. This is a promising basis for further tests under real conditions in the deep sea.
LIBS is a non-contact and virtually non-destructive method for analyzing chemical elements. It can be used to analyze solids, liquids and gases. The method is based on the generation and analysis of a laser-induced plasma. A high-energy laser beam is focused on the sample. The energy of the laser beam at the focal point is so high that a plasma is created. The plasma in turn emits element-specific radiation, which is measured using a spectroscope. The emission lines in the spectrum can be assigned to the chemical elements of the sample. The "Robotic Subsea Exploration Technologies - ROBUST" project (funding code: 690416) was funded by the European Union as part of the "Horizon 2020" program.
