Prior to establishing operation of the world’s first multiturn superconducting energy recovery linac, the Cornell-BNL energy recovery test accelerator was configured for one-turn energy recovery. In this setup, direct measurement of the beam loading in each of the main linac cavities demonstrated high energy recovery efficiency. Specifically, a total one-turn power balance efficiency of 99.4%, with per cavity power balances ranging from 99.2–99.8% was measured. When accounting for small particle losses occurring in the path length adjustment sections of the return loop, the per cavity power balances correspond to per cavity single particle energy recovery efficiencies ranging from 99.8 to 100.5%. A maximum current of $70\mu \mathrm{A}$, limited by the an incomplete radiation shielding installation around the main beam stop at the time of these measurements, was energy recovered.

• Received 26 October 2020
• Accepted 4 January 2021

DOI:https://doi.org/10.1103/PhysRevAccelBeams.24.010101

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Published by the American Physical Society