CBETA Multi-Turn Operation, Correction and Studies

Overview

CBETA was a multi-turn ERL operated at Cornell University in 2019-20. A 36MeV superconducting module was to accelerate up to 4 times to raise electron energies from 6MeV to 150MeV. The electron return loop used permanent magnets and a novel Fixed Field Accelerator (FFA) lattice that allowed all four energies from 42MeV to 150MeV to be returned in the same beam pipe. Tests of energy recovery achieved very high efficiency and 70uA circulating current in single-turn mode and partial beam recovery in 4-turn mode. This seminar also describes some of the correction procedures for the return loop orbit and adjusting path lengths in the machine. Other operational observations such as halo from the source cathode and magnet degaussing tests are also described.

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