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MEMS and Microstructures in Aerospace Applications - Robert Osiander et al (Eds) Part 5

Tham khảo tài liệu 'mems and microstructures in aerospace applications - robert osiander et al (eds) part 5', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Space Radiation Effects and Microelectromechanical Systems 93 Where no test data exist radiation testing of parts identical to those intended for space is the next step. The parts chosen for testing should have the same date and lot codes as those selected for the mission because it is well known that performance degradation during and following exposure to radiation is very device- and processdependent. Ground testing involves the use of particle proton or heavy ion accelerators for SEE and displacement damage testing and radioactive sources Co60 or x-rays for total ionizing dose testing.7 8 The kinds of degradation are identified and their dependence on particle fluence and deposited energy measured to quantify the degradation. That information is then used to predict the operation of the device in the charged particle environment of interest. Finally subsystem and system-level analyses must be undertaken to determine how the specific device degradation affects the overall spacecraft performance. Some radiation-induced effects may have no adverse effects on the system whereas others may cause system failures. In those cases where the effects are pernicious one can adopt any one of a host of measures that have been used successfully to mitigate them. Such measures might include the use of cold spares or extra shielding for devices that are sensitive to TID or protecting data with error-detecting-and-correcting codes in devices found to be SEE sensitive. When such measures are not possible the device should be discarded and an alternate one used in its place. 5.2.1 Space Radiation Interaction with Materials and Devices Ionization This section deals primarily with radiation damage by charged particles including electrons protons and heavy ions Z 2 . Most of the investigations of radiation damage have been in electronic opto-electronic and optical devices. Those results will be applied to the case of radiation damage in MEMS. The first step is to investigate the .