ces the same amount of displacement damage dose as the time-integrated transported proton spectrum representing the mission environment. Equation 5 can also be used to calculate the mission equivalent fluence at a proton energy for which there is relevant device data in the literature. In this way, one can assess the suitability of a candidate device for a particular mission, or (as often is the case) to provide an initial assessment of a device already chosen. The NIEL correlation may also be used to estimate the relative damage of protons and neutrons, which is useful since there is a large body of literature concerning neutron induced displacement damage. In the case of solar cell applications, minimal shielding is utilized. As a result such devices are subject to displacement damage dose from both electrons and relatively low energy (and more damaging) protons. In the solar photovoltaic community, it is customary to compare the degradation of various technologies to their response to 1 MeV electron irradiation. The on-orbit proton environment is expressed as a 10 MeV proton equivalent fluence, and then converted to a 1 MeV electron equivalent fluence [Tada82]. 2.3.4 Concept of "Displacement Damage Dose" The concept of non-ionizing energy deposition (e.g., NIEL) plays the same role in displacement damage effects as the ionizing energy deposition (or linear energy transfer (LET)) plays in ionization induced effects [Dale89a]. The units are the same, namely MeV/g. Although displacement damage dose has not yet been treated formally as a unit of dose, the radiation effects engineer may, for practical purposes, define a unit of displacement damage dose as 100 ergs of non-ionizing energy deposited per gram of material. This approach was introduced in 1991 to quantify displacement damage dose effects and simplify on-orbit predictions for the charge transfer efficiency (CTE) in CCDs IV-69 [Dale91, Dale92b]. The advantage of this method is that a single unit provides a simple way to compare the effective amount of disp