Research On Unit Anti-radiation Modelling Methods

The working components of space systems,military,power,communications and computer system are usually exposed in the radiation environment,which lead to system material damage and performance degradation.And it will affect the system and its sub-system efficiency,as well as the device life and mission reliability.Therefore,to ensure the ability of the system and the corresponding devices,it is very important to verify and evaluate the anti-radiation performance of complex systems or devices scientifically and reasonably,and to analyze and improve the anti-radiation reinforcement design of the system.However,due to the restrictions of fees and conditions,it is difficult to provide a large number of samples for testing the complex system.Only anti-radiation performance verification experiments for key components can be carried out.In view of the small sample and experimental difficulties,it is necessary to carry out the evaluation method and application research for anti-radiation performance of small-sample multi-factor complex system,and improve the system' s anti-radiation reinforcement design to ensure the success of system test or combat mission.Evaluating radical resistance of components or materials is the basis of the system evaluation.Hence,when evaluating the radiation resistance performance of a system,the system is first decomposed into subsystems,then subsystems are decomposed into assemblies and specific components or materials.Under a pre-determined radiation environment and within a pre-determined time period,the unit radiation resistance model depicts the ability of the unit that it meets the requirements and fulfilling its specified function.Establishing radiation resistance models of units are the basis of constructing the system model.The main research works are as follows:(1)We introduce the spatial radiation environment of complex system and related components and the radiation effect of its unit.And we also introduce the basic numerical simulation method of space radiation environment and three types of anti-radiation performance test data(binary data,failure data,degraded data)and their corresponding assessment methods.(2)Based on probabilistic statistical methods,we use the unit radiation test data to establish the unit radiation resistance probability model,and to solve the estimation of the failure/survival probability of the unit at a given radiation level.The specific research includes establishing the probability distribution model of the radiation resistance of the unit,estimating the model parameters;calculating the anti-radiation ability index of the unit that is greater than the posterior probability of a given index;for a given confidence,the unit's confidence limit of the radiation resistance index can be derived.(3)We take the radiation dose as an independent variable,and other factors such as dose rate and bias condition as covariates.Then the degradation model of how the radiation sensitivity parameter of the component changes with the radiation dose(or other equivalent dose such as non-ionization loss)is established.Based on this,we mainly establish the degraded orbit model,the degenerate model based on the Gamma process or the Wiener process,which describe the performance degradation processes of the currently known typical degradation mechanisms and provide a method for establishing these typical degradation process models for specific degradation data.(4)We introduce the data fusion method based on Bayes principle from the perspective of different conditions,different types and different sources of data fusion.The aim is to fuse the radiation performance data of different types and sources,and evaluate the radiation resistance of the unit under predetermined total radiation dose(survival probability).(5)We analyze the working principle and the radiation damage mechanism of the power MOSFET device,and analyze its experimental data and evaluate its performance through the anti-radiation performance evaluation model constructed by this paper.Finally,we summarize the research content of this paper and prospect the further work.