| The ocean is becoming an important guarantee of human economic development with its rich natural resources. Metal elements in the seafloor hydrothermal area form minerals after physical and chemical reaction, deposition and aggregation. The mineral must be detected before being mined by human beings. In recent years, the technology of underwater vehicle platform (such as:survey ships, submersibles and underwater robots, etc) has developed rapidly, which greatly benefits the deep-sea situ detection and speeds up the pace of deep-sea exploration. As an emerging technology in deep-sea detection, the laser induced breakdown spectroscopy has attracted much attention from people with features of situ, rapidity, non-contact and so on.Supported by the National High Technology Project (863), Ocean University of China is developing a deep-sea situ detection system based on laser induced breakdown spectroscopy (LIBS), to meet the need of the detection of metal ions in deep-sea hydrothermal. The LIBS system can be mounted on various types of deep-sea exploration vehicles to detect K, Na, Ca, Fe, Mn and other metal ions from deep-sea liquid and sediments under both normal and extreme circumstances. This study is an effective complement to the technology of deep-sea cationic detection, which can enhance our country’s competitiveness in the field of deep-sea exploration.As a part of the research work of deep-sea situ LIBS metal ion detection system, this paper based on the characteristics of deep-sea situ laser induced breakdown spectroscopy detection, initially builds the hardware of deep-sea LIBS metal ion situ detection system. What’s more, the present research has realized the detection and the data recording of laser induced breakdown spectra as well as the working environment monitoring and environment parameter recording of the spectrometer. At the same time, the on-off function of laser devices has been reached.This paper is composed of the following five parts:The first part is devoted to a brief introduction of the research background and significance, the working principles and development of the LIBS, the present analytical methods of deep-sea metal ions and their merits as well as demerits, and the application status in marine research of LIBS technique.The second part deals with the hardware system of the laser induced breakdown spectrometer detection, which stresses on the deck control and underwater detection. The selection of hardware devices (spectrometer, laser, industrial control computer, microcontroller, sensor, etc) is detailedly analyzed through introducing their technical index and performance parameter.The third part focuses on the software system of the laser induced breakdown spectrometer detection, including the software development environment, the compiling of software functional module (Laser switch control, Spectral acquisition, Spectrum display, Spectra recorded, Serial communication), the application of communication protocol, the definition of the RTU frame format and the function code, and the CRC check. Moreover, it introduces the realization of reading temperature, humidity, gesture, voltage and current function. It also introduces the compiling of slave computer procedure.The fourth part focuses on the performance testing and stability testing of the software. The system is verified by experiments in shallow water. In the experiment, the preliminary experiments spectral data and environmental parameters are achieved through remote control. Then the accuracy of the obtained data is analyzed, in order to lay a solid foundation for further experiments.The fifth part mainly summarizes the work of this thesis, points out its deficiencies, put forward the need to perfect suggestion, and conduct a tentative assume for future software. |
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