Undergraduate Research at Jefferson Lab

Investigation of Microphonics in C100-0 Cryomodule

Student: Victoria Lagerquist

School: Old Dominion University

Mentored By: Tomasz Plawski

The Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab uses high frequency electromagnetic fields in superconducting resonators (called cavities) to accelerate electrons for experiments. However, these cavities are experiencing major disruptions in operation due to microphonics increasing the radio frequency (RF) power needs beyond what can be delivered by the system. In order to determine the source of the microphonics, accelerometers were placed near the cavity housing (cyromodule) measuring vibrations. Data from the accelerometers was collected in tandem with data on cavity detuning and analyzed for correlation. Piezo tuners were also characterized for potential use in dynamic canceling of detuning. The measurements indicated a lack of correlation between environmental vibrations and the disruptive events. Current evidence points to helium instabilities as the culprit which may still require active cancellation. The initial characterization of the piezo shows promise towards that goal, but will require more investigation.