CBETA - the Cornell-BNL ERL Test Accelerator

Steve Peggs

The Cornell-BNL Energy Recovery Linac (ERL) Test Accelerator is under construction at Cornell University. Electrons pass through a Superconducting RF cryomodule 4 times during acceleration from 6 MeV to 150 MeV, and then decelerate 4 times. Most of the 70 m circumference consists of a return loop with a single beam pipe, using Halbach-style permanent magnet quadrupoles configured with very strong focusing optics to enable a four-fold momentum acceptance.

CBETA will be the first accelerator to combine all four key features – 4 passes, SRF, FFAG optics, and Halbach magnets – in a single accelerator. The FFAG optics are unique in demonstrating low-symmetry adiabatic transitions from arc to straight.

These technologies are directly relevant to the electron cooling of hadron beams in a next generation Electron Ion Collider (EIC), whether sited at Brookhaven National Laboratory or at Jefferson Laboratory.

There are opportunities for accelerator physics collaboration in phase 1 beam commissioning, in the design of CBETA phase 2 (and similar ERLs), and in EIC. An emerging collaboration already includes members from Jefferson Lab, STFC and other ERLs.

CBETA is funded solely by the New York State Energy Research & Development Agency, NYSERDA.