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Pulse-to-Pulse Emittance Measurement System--FARTECH, Inc., 3146 Bunche Avenue, San Diego, CA 92122-2247; 619-455-6607
Dr. Jin-Soo Kim, Principal Investigator
Dr. Jin-Soo Kim, Business Official
DOE Grant No. DE-FG03-98ER82574
Amount: $600,000
Beam emittance is a critical parameter for accelerator applications, including colliders and radiation-generation instrumentation (e.g., free-electron lasers). Currently, there is no technique for non-destructive, pulse-to-pulse emittance measurement. The only present technique for high-energy electron beams employs wire-scanners, requiring multiple machine pulses (large beam-time requirement for tune-up) and large capital costs ($100k per scanner for 8 scanners). In addition, these systems are mechanically fragile, necessitating continual maintenance. A quad-cavity based technique, permitting measurement of beam quadrupole moments on a single pulse, without beam interception and without moving parts, has been conceived. This system can reduce the beam tune-up time from days to seconds, resulting in enormous cost-reduction and enhancement of beam luminosity. During Phase I, the systematics of the cavity pickup (common-mode, electronics), via electromagnetic modeling of the cavity, were analyzed and structure dimensions (cavity and couplers) were calculated. A conceptual design was also produced, including the magnetic lattice and cavity placement in the beamline. This emittance measurement system, accounting for magnetic lattice and cavity-derived systematic errors, was shown to determine 30-micron rms emittance. In Phase II, radio frequency properties of the quad-cavity, with and without the coupling network, will be measured, and the results compared with the calculations from Phase I. Then, a prototype quad-cavity system will be fabricated, bench-tested, and tested at the Next Linear Collider Test Accelerator (NLCTA) beamline. These tests will include the calibration of electronics via corrector scans, the performance of quad scans, assess resolution, and dynamic range.
Commercial Applications and other Benefits as described by the awardee: The technique for in-line, non-destructive, pulse-to-pulse, measurement of beam emittance can be applied to all particle accelerators where maintaining beam quality is crucial, from high energy physics accelerators to medical application accelerators. The quad-cavity system should offer superior functionality (pulse to pulse resolution) at a much lower cost (a factor of ten of more) than presently available wire scanner systems.