Study On Control And Acquisition System Of Laser Speckle Interferometry Diagnosis Of The First Wall Morphology Of Tokamak

During the tokamak operation,the in-situ online diagnosis of the plasma facing materials(PFMs)is very important to ensure the tokamak operation safety and prolong the operation cycle.The main contents of this thesis include the development of speckle interferometry for the automated control of the wall topography diagnosis of tokamak and related experimental studies.The non-contact,full-field measurement technology of laser speckle interferometry has great application prospects in real-time on-line diagnosis of the topography of tokamak devices.Therefore,in this thesis an automatic sequence control and data acquisition system based on the LabVIEW program has been established on a laser speckle interference experimental platform.The specific research content and the resulting conclusions include the following aspects:(1)The measurement principle of laser speckle interferometry was introduced and a single wavelength laser speckle interference experimental system based on Michelson interference and Mach-Zehnder tetragonal interferometry was established.Through the experimental measurement of the two interference modes,the advantages and disadvantages of the different interference modes are obtained,which lays the foundation for improving the measurement accuracy of the experiment.(2)Using the LabVIEW program,the remote integrated control and data acquisition functions of the experimental platform has been realized.First,an independent LabVIEW subroutine for each experimental device(laser,piezoelectric ceramic,and CCD camera),and then integrated the three subroutines was been carried out.The program sets the timing and implements their timing control functions.Finally,the MATLAB program is called in the Lab VIEW program to achieve the docking of the data acquisition topology output.All the program segments were integrated and debugged,and the integrated program was applied to the speckle interference experimental platform.The remote timing control of the experimental platform was realized,and the remote real-time monitoring of the morphology of the wall sample to be measured was initially completed.(3)To build an improved Mach-Zehnder four-corner interferometer,laser ablation to simulate the erosion of plasma-facing materials(PFMs),such as molybdenum(Mo)and tungsten(W)was applied.Different kinds of samples were tested experimentally,and the morphology and information of the ablation craters obtained with the different laser ablation pulses for the two samples were investigated.The experimental feasibility tests of laser ablation morphology of the craters on Mo and W materials were successfully completed by laser speckle interferometry.