Study Of Large Incident Face Electron Gun In The Simulation Of Space Geomagnetic Substorm Environment

Space charging effect is one of the major threats on spacecraft operational safety. In ground study, the design and utilization of dispersive electron guns as simulation sources is a challenging job. This thesis focuses on the designing and testing of an electron gun with large incident face.Chapter 1 reviews the correlated background, and provides the scope along with the guideline for the author's study.Chapter 2 introduces the space environment of geomagnetic substorm and its detrimental surface charging effects.Chapter 3 describes the pre-design computation for optimization. Discussion is made on the CAD results.Chapter 4 concentrates on the practical design of the electron gun with large incident face which includes cathode selection and structure finalizing. The influence of geomagnetic field and its countermeasure is analyzed. The power supply for the electron gun is described in brief.Chapter 5 demonstrates the preliminary examination process on the electron gun in question in the F 1.2m vacuum chamber including HV resistance validation and measuring of cathode emission and beam current on the target plane. Factors influencing emission stability and beam current uniformity are discussed. The result lay the basis for following testing.Chapter 6 presents the approach for testing of the electro gun in the large space geomagnetic substorm simulation device. Emphases are made on the nano-Amp current measuring scheme together with the design of the specific cables, flange, electrodes and insulative envelopes of HV transmission.The conclusion remark summarizes the originality of this thesis, and gives recommendation for the furthering work.