Energy recovery linacs in high-energy and nuclear physics

Energy recovery linacs (ERL) have significant potential uses in high energy physics and nuclear physics. We describe some of the potential applications which are under development by our laboratories in this area, and the technology issues that are associated with these applications. The applications that we discuss are electron cooling of high-energy hadron beams and electron-nucleon colliders. The common issues for some of these applications are high currents of polarized electrons, high-charge and high-current electron beams and the associated issues of high-order modes. The advantages of ERLs for these applications are numerous and will be outlined in the text. It is worth noting that some of these advantages are the high brightness of the ERL beams and their relative immunity to beam-beam disturbances.