26–31 Oct 2025
Wang Center
America/New_York timezone

BBU Thresholds and Digital Feedback Suppression for Frequency-Scaled BNL Cavities in the EIC Energy-Recovery Linac

THC2
30 Oct 2025, 13:30
30m
Wang Center

Wang Center

Stony Brook University campus, Stony Brook, New York
Contributed Oral Presentation COOL'25 Cooling Technology

Speaker

Sadiq Setiniyaz (Thomas Jefferson National Accelerator Facility)

Description

The Electron–Ion Collider (EIC) achieves its design luminosity by cooling the ion beam with a high-current electron beam generated in an energy-recovery linac (ERL). The baseline ERL lattice employs a BNL five-cell cavity that is frequency-scaled to 197 MHz, 591 MHz, and 1.773 GHz, raising concerns about multibunch beam-breakup (BBU) instabilities. Threshold currents for each frequency option are established with two independent BBU tracking codes, providing cross-validated operating margins that guide cavity selection. To further increase the current limit, we incorporate a digital transverse feedback (FB) system that targets the dominant higher-order modes (HOMs). Simulations show the FB raises the BBU threshold by roughly an order of magnitude: power-spectral-density analysis of the beam centroid at the linac exit confirms strong suppression of the aliased HOM peak, although some spectral growth appears at secondary frequencies. This combined study quantifies baseline BBU limits, demonstrates effective active mitigation, and charts a practical path toward robust, high-current operation of the EIC ERL.

Funding Agency

This work was produced in part by Jefferson Science Associates, LLC under Contract No. AC05-06OR23177 with the U.S. Department of Energy.

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Authors

Isurumali Neththikumara (Thomas Jefferson National Accelerator Facility) Kirsten Deitrick (Thomas Jefferson National Accelerator Facility) Dr Nicholas Sereno (Argonne National Laboratory) Sadiq Setiniyaz (Thomas Jefferson National Accelerator Facility)

Presentation materials

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