Fast Ferroelectric L-Band Tuner

An Energy Recovery Linac for the electron cooler of the Relativistic Heavy Ion Collider at Brookhaven National Laboratory is now being developed to provide a necessary luminosity upgrade for the collider. But a new means is needed to stabilize the linac on a rapid time scale against fluctuations in beam loading and microphonics ¿ current ferrite tuners are not fast enough for this application. This project will develop a fast 700 MHz tuner for this application that will employ ferroelectric phase shifters, which can be rapidly tuned by application of an external voltage. This tuner will have two ferroelectric phase shifters in the arms of a magic-T waveguide element, which can effect independent amplitude and phase control of the power incident on the cavities. The fast tuner, which will maintain superconducting cavity matching to the radio frequency (RF) feed lines in the Energy Recovery Linac, will be designed in Phase I and will be built and tested in Phase II. Commercial Applications and other Benefits as described by the awardee: For the Energy Recovery Linac, four ferroelectric tuners would be required, providing a modest return on the R&D investment. However, once the first version of the tuner is demonstrated, a far larger market should exist for the tuning of superconducting cavities in many other accelerators, cooling rings, and related devices.