| Laser probe,also known as laser-induced breakdown spectroscopy(LIBS),is a material composition analytical technology that based on emission spectrum of laser-induced plasma.LIBS has numerous advantages such as less sample preparation,fast,real-time,in situ,and simultaneous multi-element analysis.,and it has great potentials for applications in many fields,such as metallurgy,environmental protection,space exploration,biological medicine and materials science.However,the conventional LIBS system is inconvenient when it applied in the occasion of in situ and fast detections due to its large size and high energy consumption.Those problems restricts its wider applications.In this thesis,a handheld laser probe analyser and a compact synchronizer for LIBS were designed and realized to miniaturize LIBS.The detailed contents are as follows:A compact synchronizer with 5 channels and 55 ps resolution was designed and realized using a microcontroller unit and simple circuits.It could reduce the size,energy consumption and cost of the synchronizer sharply,which are the key points of LIBS system controlled by the conventional general digital delay generator of DG535.Compared with DG535,the self-developed synchronizer has the almost same performance and more suitable for compact LIBS instrument,which satisfies the requirements of in situ and fast LIBS applications.A handheld laser probe analyser was designed and integrated by a compact pulse laser,a mini fiber optic spectrometer and a embedded computer.The analyzing and controlling software running on customized embedded Linux system is developed for this analyser.And then the integreation of hardware and software system was accomplished successfully.The practical test results show that the analyser is portable,easy-to-use,and capable of fast analysis.which meets the demand of in suit analusis.A fast identification model that based on principal component analysis and mahalanobis distance discrimination was built and integrated the handheld laser probe analyser.For applying in the identification of seven different kinds of reference samples of aluminum alloy,the results show that the accuracy is more than 93.33%,and the analytical time of one test is about 4 seconds. |
