Highly Efficient RING-Cavity Laser Wire Scanner for Intense CW Electron Beams

High-current, high-power particle beam collider facilities require non-intrusive means for measuring the quality of their beams—especially the transverse emittance. Previously invented means—including wire scanners, scintillating screens, optical transition radiation screens, pepper pots, and emittance slits—all suffer from the same vulnerability: any material object placed in the beams path will be destroyed by the beam. An alternative means of measuring the beam’s transverse phase space is required so that operators can properly tune the beam for maximum efficiency, power, and luminosity. Building on prior projects, RadiaBeam proposes to design a laser wire scanner system that can measure high-intensity beams without fear of the beam damaging the system, nor of the system spoiling the beam. The laser wire scanner uses a unique beam recirculation design (Recirculation Injection by Non- linear Grating, or RING) to build up a high-intensity laser beam that will increase the scattering signal and reduce the required laser power compared to previous laser wire scanner designs. The proposed research will advance this type of beam diagnostic by greatly enhancing the efficiency of the interaction. Phase I of this project will consist of designing the major components of the system: the RING laser cavity, the vacuum chamber, the detection system, and, at the request of Jefferson Lab, integrating a Compton scattering electron beam polarimeter. The work in this phase will result in a set of specification that will guide the engineering effort of Phase II. Commercial Applications and Other Benefits: The RING cavity is a critical technology for the high repetition rate laser wire scanner application. Such systems can also find a broader use in the creation of extreme ultraviolet light or X-rays for solid state semiconductor and medical imaging and treatment applications.