and electron degradation. The fits are shown in figure 28, and we see the proton data correlate well with NIEL over the energy range from 0.2 to 9.5 MeV. For electrons, they find that the best agreement of the data over the largest energy range is obtained when the calculated NIEL was raised to the 1.7 power. As a result, they define the equivalent 1 MeV electron displacement damage dose as the product of the particle fluence with NIEL raised to the 1.7 power. This example illustrates one method of modifying the NIEL correlation in order to perform an on-orbit prediction for a quantity that does not exhibit the energy dependence predicted by NIEL. Obviously, other fitting approaches can also be employed to describe the measured device degradation after irradiation, and all require measurements of the device degradation for a set of particle energies. IV-98 4.0 SUMMARY Section IVB begins by examining the process by which incident protons displace atoms in semiconductor material and ultimately produce electrically active defect levels. The impact of displacement damage induced defects on the operation of semiconductor devices is described. In general, devices whose primary characteristics depend on the minority carrier lifetime will be most sensitive to displacement damage. The concept of the non-ionizing energy loss rate (NIEL) is introduced, and it is shown that in many cases device degradation as a function of proton energy is approximately linearly dependent on the NIEL for a variety of materials. This means that the NIEL is the displacement damage equivalent of the LET for total ionizing dose effects. We present displacement damage tools (based on NIEL or experimental damage functions) that allow on-orbit prediction of device degradation based on a small number of laboratory measurements. Limitations in the application of NIEL are also discussed. We find that experimental data for Si and GaAs devices show that NIEL overpredicts device degradation at higher proton energies. Finally, we presented a series of cas