e: Growth of concern for proton effects over the past decade Topic IEEE TNS, Vol. 35, No. 6, 1988 IEEE TNS, Vol. 45, No. 6, 1998 Environments Dosimetry Displacement Damage "Traditional" SEE New Effects Total 9 (~10% of total) 26 (~30% of total) In the recent Transactions, four papers were devoted to effects that were either unknown or considered unimportant a decade earlier. These include soft errors from direct ionization by protons [Mars-98, Reed-98] and from nuclear elastic scattering events [Ingu-97, Savage-98, Johnston-98], along with hard failure SEE mechanisms such as latch-up [Norm- 98] and dielectric breakdown in power MOS devices [Titu-98]. The aggregate level of concern is obvious with a total of 26 papers, or about one third of the articles, in the 1998 December TNS dealing substantially with proton-related issues. In this Short Course segment we will attempt to survey the important developments that have taken place in the past few years. The material we cover emphasizes the developments affecting design tradeoffs for current satellite systems with the recognition that any given component can potentially be used SO long as the risks are identified adequately and mitigated appropriately. We approach this task by citing the studies that identify the various effects that protons can have, and then by indicating and demonstrating the tools available to radiation effects experts and knowledgeable designers to quantify the associated risks. To place the material in the context of the needs of the satellite design engineer, we offer the following list of reasons that might motivate the need for proton testing of a given device or circuit. Reasons to test with protons: Expect proton SEEs and have no satisfactory means of predicting response without proton test data. Have no SEE data on part type and need to characterize for a proton rich environment Have heavy ion SEE data and correlation approaches indicate "marginal" performance Need to gain general idea of heavy ion sensitivity and have package penetratio