| Electron Diffraction is a unique method for studies of matter structure and phase transitions, and a promising approach to analyze the basic process in the nature, such as the transformations of matter properties and matter structure, the chemical reactions and the biologic reactions. The time-resolved electron diffraction becomes a more preferred method because it can provide real-time information of the matter's physical, chemical and biological characteristics. With the constantly understanding of the micro-world, the demand of the system's time resolution becomes higher and higher.In recent years, many foreign laboratories are engaged in this field, and developed the picosecond electron diffraction systems and femtosecond electron diffraction systems successfully.A sweeping and synchronizing circuit of the femtosecond electron diffraction system (FED) is designed and fabricated. The falling edge of the output waveform is fast and sharp, so the sweeping speed of the whole system is promoted and the time resolution is decreased. This circuit can be used to measure the pulse width of the electron bunch.In this thesis, the construction of the FED system is introduced, and the components of the femtosecond electron gun are explained in detail. According to the demand of the system time resolution, the parameters of the circuit are decided. Then the circuit design is analyzed detailedly, such as the theory of avalanche transistors and the theory of coplanar waveguide transmission line. Finally the output of this circuit is measured. The slope of the falling edge is 5.6kV/ns, and the trigger delay is 9ns. |
