Jefferson Lab, Newport News, Virginia
IUCF, Bloomington, Indiana
BTG, New York
BNL, Upton, Long Island, New York
ANL, Argonne, Illinois
Experiments on the study of fundamental quark-gluon structure of nucleons require an electron-light ion collider of a center of mass energy from 20 to 65 GeV at luminosity level of 1035 cm-2s-1 with both beams polarized. A CEBAF accelerator based ring-ring collider of 7 GeV electrons/positrons and 150 GeV light ions is envisioned as a possible next step after the 12 GeV CEBAF Upgrade. The developed ring-ring scheme takes advantage of the existing polarized continuous electron beam and SRF linac, the green-field design of the collider rings and the ion accelerator complex with electron cooling. We report results of our design studies of the ring-ring version of an electron-light ion collider of the required luminosity.
Tech-X, Boulder, Colorado
BNL, Upton, Long Island, New York
ORNL, Oak Ridge, Tennessee
AES, Princeton, New Jersey
Fermilab, Batavia, Illinois
Jefferson Lab, Newport News, Virginia
BINP SB RAS, Novosibirsk
JINR, Dubna, Moscow Region
The physics interest in a luminosity upgrade of RHIC requires the development of a cooling-frontier facility. Detailed cooling calculations have been made to determine the efficacy of electron cooling of the stored RHIC beams. This has been followed by beam dynamics simulations to establish the feasibility of creating the necessary electron beam. Electron cooling of RHIC at collisions requires electron beam energy up to about 54 MeV at an average current of between 50 to 100 mA and a particularly bright electron beam. The accelerator chosen to generate this electron beam is a superconducting Energy Recovery Linac (ERL) with a superconducting RF gun with a laser-photocathode. An intensive experimental R&D program engages the various elements of the accelerator: Photocathodes of novel design, superconducting RF electron gun of a particularly high current and low emittance, a very high-current ERL cavity and a demonstration ERL using these components.
Fermilab, Batavia, Illinois
The Recycler is the primary antiproton repository for the Tevatron collider at Fermilab. Stored antiproton beam intensity has been steadily increased to about 450·1010 over the last three years. We have used the technique of longitudinal momentum mining* in the Recycler to extract constant intensity and constant longitudinal emittance antiproton bunches for collider operation since early 2005. Since then, the Recycler has played a critical role in the luminosity performance of the Tevatron; the peak proton-antiproton luminosity has been raised by a factor of about three and a world record luminosity of 2.31·1032cm-2s-1 has been achieved. Recently, many improvements have been implemented in the antiproton mining and stacking schemes used in the Recycler to handle higher intensity beam. In this paper we discuss morphing during antiproton stacking, reducing longitudinal emittance dilution, and use of soft mining buckets to maintain low peak density and control the beam instability during mining. In addition we present past and current performance of mining and beam stacking RF manipulations.
* C. M. Bhat, Phys. Letts. A Vol. 330 (2004), p 481