HIGH HEAT LOAD OPTICS - AN HISTORICAL OVERVIEW

As power levels of synchrotron beamlines increase, the heat flux on optical components attains or exceeds levels of that for high-energy laser (HEL) optics. The synchrotron technical community may benefit from the experiences gained as a result of the development activities associated with cooled mirrors for HELs. Such activities span a period of about 25 years, consider numerous design concepts, and evaluate many construction materials along with related fabrication processes. The quantity of work performed on cooled mirrors for HELs is too extensive to allow a single paper to summarize all potentially useful information. The purpose of this overview is to highlight much of the past work, with emphasis on more recent technology, and to provide a bibliography that should aid in accessing pertinent literature. Although heat loads are similar, hundreds of watts per square centimeter, some aspects of the laser and synchrotron application differ. Generic characteristics of each are summarized before prior cooled laser mirror technology is discussed. This should allow a meaningful assessment of the applicability of prior heat exchanger designs, material selections, and operational experiences to synchrotron beamline usage.