Research On Numerical Simulation And Application Of Deep Dielectric Charging Effect

Deep Dielectrics Charging effect due to interactions between high energy electrons and spacecraft dielectric materials seriously threatens the objects of long life and high reliability for on-orbit spacecraft missions, and also is a hot research direction in Spacecraft Charging Effect and Protection Technology field in recent years. Currently, it becomes a common numerical simulation method to solve analysis and evaluation of spacecraft environmental effects by introducing Monte Carlo particle transfer simulation into concrete space environmental effect models.The paper firstly reviews state of art and developing trends for current space deep dielectrics charging effect research and puts forward an new GEANT4-RIC numerical method in that GEANT4 particle transfer simulation package is used to realize radiation simulation in deep dielectrics charging process and Radiation-Induced Conductivity model is used to calculate internal electric field of dielectrics. It is studied that the physical processes and statistical method of detecting parameters involving in the internal charging with GEANT4 simulation. Moreover, RIC equations of dielectric structures are derived for deep dielectrics charging simulation. Through calculating examples of publish literature, the effectiveness of this evolution method is verified by contrast in charge density and surface voltage and profile of internal field.On the basis of GEANT4-RIC method, influence of density and thickness and conductivity of dielectric for deep dielectrics charging effect is investigated. The FR4 and TEFLON law deep dielectrics charging is obtained in space electron environment model of FLUMIC2, result indicate that (1) density of dielectric have affected profile of charge density in deep dielectrics charging, charge density will increase with density of dielectric; (2) thickness of dielectric have affected profile of internal field, internal field will increase with thickness of dielectric when thickness less than electron distance; (3) conductivity of dielectric have obviously affected internal field, dielectric will bring serious charging problem when conductivity less than 1e-14Ω-1m-1.The paper firstly use the method of GEANT4-RIC in manufacture of Internal Discharging Monitor(IDM). Charging process of FR4 print circuit board using in IDM is simulate under rear grounding, result indicate average discharging time of sample under 1MeV,10pA/cm2 energetic electron radation is 4.6 munites. It is very close to testing result of average discharging time.According to the structure features of discal ring and operation, RIC maths model of 3-D is established and calculate the three charging state without radiation and ideal dielectric RIC model diectric under radiation, primarily validate ability that GEANT4-RIC deal with deep dielectrics charging of 2-D and 3-D complex structure as a universal method.Finally, the GEANT4-RIC method is also introduced to research proton induced internal charging problem. The simulations prove its feasibility on predicting and evaluating dielectric intenal charging effect and also provide an alternative way for proton induced internal charging research.