Causes and Solutions of Pseudo Shift of Diffraction Peak in Short Wavelength Characteristic X-ray Diffraction

The stress of the sample was measured by short wavelength characteristic X-ray diffractometer. It was found that the diffraction angle obviously deviated from the theoretical diffraction angle during test the diffraction peak near the sample surface. The reason for pseudo migration of diffraction peak was analyzed by theory and experiment, and the solutions were put forward. The results show that due to the wave length of the short wavelength characteristic X-ray was short and the diffraction angle was small, the gauge volume cross section formed by the incident collimator and the receiving collimator was a long diamond. When the sample was not filled with the gauge volume, leading to the pseudo shift of diffraction peak, resulting in the error of the diffraction angle measurement and affecting the accuracy of strain calculated results. The influence of pseudo shift of diffraction peak on strain calculated results could be reduced by reducing the width of collimator, using high angle diffraction peak, using symmetry method, turning sample and using ideal reference sample.