Proton Effects and Test Issues for Satellite Designers

This portion of the Short Course is divided into two segments to separately address the two major proton-related effects confronting satellite designers: ionization effects and displacement damage effects. While both of these topics are deeply rooted in "traditional" descriptions of space radiation effects, there are several factors at play to cause renewed concern for satellite systems being designed today. For example, emphasis on Commercial Off-The-Shelf (COTS) technologies in both commercial and government systems increases both Total Ionizing Dose (TID) and Single Event Effect (SEE) concerns. Scaling trends exacerbate the problems, especially with regard to SEEs where protons can dominate soft error rates and even cause destructive failure. In addition, proton-induced displacement damage at fluences encountered in natural space environments can cause degradation in modern bipolar circuitry as well as in many emerging electronic and opto-electronic technologies. A crude, but nevertheless telling, indication of the level of concern for proton effects follows from surveying the themes treated in papers presented at this conference. The table lists themes found in the IEEE Transaction on Nuclear Science (TNS) December issue from the past year and compares them with the December issue's content a decade earlier. Ten years ago there were nine papers, or about 10% of the total, dealing with the four indicated topics. At that time, single event effects from protons were the primary concern, and these were thought to be possible only when a nuclear reaction initiated energetic recoil atoms. This is shown in the table as the 'traditional" SEE subject. A decade later, submissions addressing this topic had doubled, while papers devoted to displacement damage studies had increased from one to nine! More importantly, displacement damage effects in the natural space environments have become a concern for degradation in modern devices (other than solar cells), and this was not so ten years earlier.