Testing electronic parts from flight lots on dose effects for the hardness guarantee of spacecraft onboard equipment

The main results for radiation testing electronic parts of flight lots on dose effects of long-time low-intensive influence of space ionizing radiation is observed. Such test approach provides for the given component a computational-experimental radiation design margin estimation, which is based on part's experimental radiation hardness determination at the stage of the spacecraft onboard equipment acquisition. The test complex includes two Co-60 panoramic gamma apparatuses with adjustment of gamma-radiation dose rate in a range from 0,1 rad/s to 0,01 rad/s, and a dosimetry system for calibration of a gamma-radiation field in terms of the dose absorbed in silicon with uncertainty no more than 2,5 %. The results of testing bipolar parts manufactured in Russia have shown that as the dose rate decreases, radiation hardness depending on the change in the dose rate may either increase or decrease. Incidental uncontrollable changes in the production technologies of parts occurring within a period of time less than a year and causing changes in radiation hardness of parts on dose effects to an order of magnitude are found out. If the absorbed dose is less 30 krad for bipolar parts the dose rate effect can be found out on the basis of a higher recovery rate of parts parameters after irradiation at high dose rate in the course of the subsequent annealing at room or raised to 100 °С temperature. It is shown that under the conditions of the time-varying dose rate that models aftereffects of high-power Sun flash, the bipolar parts characterized by the effect opposite to ELDRS, temporary parametric failure is detected. The discovered dose effects are offered to be taken into consideration when updating the standard test methods.