ELIC is an electron-ion collider with center of mass energy of 20 to 90 GeV
and luminosity up to 8x1034 cm-2s-1.
This high luminosity collider is envisioned as a future upgrade of CEBAF, beyond
the 12 GeV Upgrade, and compatible with simultaneous operation of the 12 GeV CEBAF
(or a potential extension to 24 GeV) for fixed-target experiments.
The CEBAF accelerator with polarized injector can be used as a full energy
injector into a 3-9 GeV electron storage ring. A positron source is envisioned
as an addition to the CEBAF injector, for generating positrons that can be
accelerated in CEBAF, accumulated and polarized in the electron storage ring,
and collide with ions with luminosity similar to the electron/ion collisions.
The ELIC facility is designed to produce a variety of polarized light ion
species: p, d, 3He and Li, and unpolarized ion species. To attain the required
ion beams, an ion facility must be constructed, a major component of which is a
225 GeV collider ring located in the same tunnel and below the electron storage
ring. A critical component of the ion complex is an ERL-based continuous electron
cooling facility, anticipated to provide low emittance and simultaneously very
short ion bunches.
ELIC is designed to accommodate up to four interaction regions (IR’s),
consistent with realistic detector designs. Longitudinal polarization is guaranteed
for protons, electrons, and positrons in all four IR’s simultaneously and for
deuterons in up to two IR’s simultaneously.
An alternate design approach for ELIC is based on the linac-ring concept,
in which CEBAF operates as a single-pass Energy Recovery Linac (ERL) providing
full energy electrons for collisions with the ions.
Although this approach promises potentially higher luminosity than the ring-ring
option, it requires significant technological advances and associated R&D.
A linac-ring ELIC design is an ultimate Upgrade of ELIC, fully compatible
with and a natural extension of the ring-ring scheme.