SHIELDING CONSIDERATIONS FOR SATELLITE MICROELECTRONICS

Shielding for space microelectronics needs to provide an acceptable do se rate with minimum shield mass. The analysis presented here shows th at the best approach is, in general, to use a graded-Z shield, with a high-Z layer sandwiched between two low-Z materials. A graded-Z shield is shown to reduce the electron dose rate by more than sixty percent over a single-material shield of the same areal density. For protons, the optimal shield would consist of a single, low-Z material layer. Ho wever, it is shown that a graded-Z shield is nearly as effective as a single-material shield, as long as a low-Z layer is located adjacent t o the microelectronics. A specific shield design depends upon the deta ils of the radiation environment, system model, design margins/levels, compatibility of shield materials, etc. Therefore, we present here ge neral principles for designing effective shields and describe how the computer codes are used for this application.