Design and fabrication of a ferrite-lined HOM load for CESR-B

The beam tubes on the CESR-B cavity have been designed so that all of the higher order modes (HOM´s) will propagate out of the cavity. To damp these modes to Q values of ~100, we have proposed the use of HOM loads that are an integral part of the beam tube, though located outside the cryostat. The absorbing medium is ferrite tiles which are bonded to the inside of a 304 series stainless steel water-cooled jacket. The bonding agent is an alloy which melts at ~220°C. This alloy provides good thermal, as well as electrical, conductivity. Calculations indicate that these loads will provide the necessary damping and measurements using full-size models have verified this. It is anticipated that each HOM load for CESR-B will have to absorb 10-20 kW of beam induced power. High power tests of a scale model of the CESR-B load have been performed. The full-size load awaits final construction to be followed by testing