1. Other issues and concepts under study Conclusions References
Thomas Jefferson National Accelerator Facility
Newport News, Virginia, USA
Ion Beam Stability
Short Ion Bunches and Low *
Cooled p-bunches in a ring with SRF cavities
Final focus of ELIC with short bunches (p/e)
Strong SRF -> high synchrotron tune (0.06) which helps stabilize short ion bunches against microwave instabilities and beam-beam interaction.
Crab Crossing
Short bunches make feasible the Crab Crossing
SRF deflectors 1.5 GHz can be used to create a proper bunch tilt
Parasitic collisions are avoided without loss of luminosity
Spin in ELIC
Other issues and concepts under study
Ion Complex
Polarized He and Li sources (cooperating with IUCF)
Stacking intense low emittance polarized ion beams from negative and positive sources overcoming space charge limitations (cooperating with IUCF and ORNL)
SRF control in ion ring
Electron complex
High current (2-25 mA) polarized source
Multi GeV energy recovery (recovery of 1 GeV has been demonstrated successfully at CEBAF)
SRF control and beam stability in ERL
Fast kickers for ERL with circulator ring
CSR in circulator ring
“Figure-8” boosters and collider rings:
Zero spin tune avoids intrinsic spin resonances
No spin rotators required
Longitudinal to transverse ion spin control, stabilization and fast flipping can be provided for all polarized species at all energies by the weak steering dipole magnets (distributed around arcs) in cooperation with solenoids in straights
Spin stability issue is practically gone
  Solenoids in electron arcs and helical Siberian Snakes in ion arcs can be used to obtain longitudinal spin for electrons and protons at 4 interaction points simultaneously
Conclusions
An excellent scientific case starts developing for a high luminosity, polarized electron-light ion collider, to address fundamental questions in Hadron Physics
JLab design studies have led to an approach that promises luminosities from 1033 cm-2 sec-1 up to nearly 1035 cm-2 sec-1, for electron-light ion collisions at a center-of-mass energy between 20 and 65 GeV
This design can be realized using energy recovery on the JLab site and can be integrated with a 25 GeV fixed target program for physics
Planned R&D will address open readiness issues
References
L. Merminga, Ya. Derbenev, ELIC: A High Luminosity and Efficient Spin Manipulation Eliectron-Light Ion Collider at CEBAF, CIPANP 2003
Ya. Derbenev, et.al, ELIC Design, 2nd EIC Workshop, JLab 2004
Ya. Derbenev, Feasibility of Electron Cooling and Luminosity Potentials of Colliders, NIM A 2004