Discussion the Location of Simulation Crystal in Microwave Bragg Diffraction Experiments

The microwave wavelength was determined by Michelson interference experiment at first,and then by changing the location of simulation crystal and the relationship between the incident angle and the diffraction intensity of( 110) crystal plane was measured,the situation was studied to agree with the Bragg's law. When the position of the crystal is located in the center of the experimental apparatus of microwave integrated optical,the data meet the Bragg's law very well. When the crystal is located in the front of the center,the Bragg diffraction peak moves to the right and the diffraction angle increases. Instead,when the crystal is located in the back of the center,the Bragg diffraction peak shifts to the left and the diffraction angle decreases. Compared with the actual crystal powder X-ray diffraction experiment,in theta-2theta scanning mode,when the sample amount is too little,i. e. sample sag,the diffraction angle becomes smaller and diffraction peak shifts to the left. As well,the sample amount is too much,i. e. sample projection,the diffraction angle becomes larger and diffraction peak shifts to the right. These results are similar nature in these experiments. However,the microwave Bragg diffraction experiment is a visual image to facilitate students understanding of X-ray diffraction experiment.