Investigation of the Radiation Resistivity of Large Scale Integrated CMOS-RAM´s

The investigations we report here were intended to show if LSI-CMOS-RAM´s are able to survive the passage through the radiation belt of Jupiter during the fly-by phase of the ISPM-mission. Attempts were made to obtain samples of all the 1024 word × 4 Bit and 2048 word × 8 Bit RAM´s currently on the market. There are still no CMOS-RAM´s commercially available that survive this degree of irradiation. We found considerably different radiation resistancy depending upon the mode of usage of the CMOS-RAM´s. The best procedure is to switch them off during fly-by phase.