High Precision Integrated Beam Position and Emittance Monitor

72755-Beam position and emittance are critical parameters for accelerator applications, including colliders and radiation generation, as in free-electron lasers. A high precision emittance measurement requires precise beam position at the measurement location. At present there is no existing technique, commercial or otherwise, for non-destructive, pulse-to-pulse, simultaneous beam position and emittance measurement. This project will develop a high precision, cavity-based system for simultaneous, pulse-to-pulse beam position and emittance measurements, without beam interception or moving parts. A multi-cavity standing wave structure will be designed, fabricated, and tested, in which the quadrupole and the dipole standing wave modes resonate at harmonics of the beam operating frequency. Phase I designed an optimized 9-cavity standing wave system for simultaneous high precision beam position and emittance measurements. An integrated system was designed so that the quadrupole of the system operates with the pi-mode resonating at the 16th harmonic of the bunch frequency at the Next Linear Collider (NLC), and with the 3pi/4 dipole mode resonating at 12th harmonic. The output field amplitude of the system was close to 9 times that of a single cavity system, resulting in better resolution. In Phase II, the 9-cavity standing wave structure will be fabricated. The complete system will be tested using the beams at the NLC Test Accelerator at the Stanford Linear Accelerator Center. Commercial Applications and Other Benefits as described by awardee: The high precision, integrated, position-emittance measurement technique should be applicable to all particle accelerators where maintaining beam quality is crucial, from high energy physics accelerators to medical application accelerators. The system should offer superior functionality (pulse-to pulse resolution) at a much lower cost (a factor of ten or more) compared to presently available wire scanner systems.