Radioactivity and damage studies for next generation colliders

Optimization of the average, generalized luminosity per unit cost of a linear collider requires a detailed study of this Figure-of-Merit. We consider what might be called a triangle inequality between damage, efficiency and cost. Examples over the length of an LC, starting at the source and ending at the dump, suggest that both costs (capital and operating) and environmental issues can be improved in a compatible way. Thus, a RoHS by any other name (WEES or OSHA) need not present thorny problems requiring unexpected R&D but a push to leverage the most recent advances in materials and technology. Further, the true amortized cost may be seriously underestimated by ignoring such issues. As example, the entire, interior surface of a laser driven RF gun involves materials science where the space requires continuous UHV to sustain stable, acceptable quantum efficiency as well as avoid RF breakdown damage in an environment that is also subject to radiation damage. All of these can seriously reduce the gun´s output and an LC´s luminosity. Dealing with them provides opportunities to innovate that can justify the costs.