Theoretical study of deflection-scan subsystem of femtosecond electron diffraction system based on relativistic correction

The deflection-scan subsystem of the femtosecond electron diffraction system was theoretically studied and an exact solution of the deflection distance was got. The numerical calculations under relativistic correction and non-relativistic correction show that the difference of the deflection distances is about 61.4 mm, and the difference of the electron pulse widths is about 65 fs. The result can be useful for the design of the subsystem and the test of the time resolution of the ultra-fast electron diffraction system, especially for the synchronization process of the test.