ANL, Lemont, Illinois, USA
JLab, Newport News, Virginia, USA
A recent assessment of the scientific merit for a future Electron Ion Collider (EIC) in the US, by the National Academy of Sciences, found that such a facility would be unique in the world and would answer science questions that are compelling, fundamental, and timely. This assessment confirmed the recommendations of the 2015 Nuclear Science Advisory Committee for an EIC with highly polarized beams of electrons and ions, sufficiently high luminosity and variable center-of-mass (CM) energy. The baseline design of Jefferson Lab Electron-Ion Collider (JLEIC) has been updated to 100 GeV CM energy, corresponding to 200 GeV proton energy. We here present a high-energy design for the JLEIC ion complex. It consists of a 135 MeV injector linac, a 6-GeV non figure-8 pre-booster ring and a 40-GeV large ion booster, which could also serve as electron storage ring (e-ring). The energy choice in the accelerator chain is beneficial for a future upgrade to 140 GeV CM energy. The large booster is designed with the same shape and size of the original e-ring allowing for the option of building separate electron and ion rings by stacking them in the same tunnel along with the ion collider ring.
ANL, Lemont, Illinois, USA
Illinois Institute of Technology, Chicago, Illinois, USA
As part of the alternative design approach for the Jeffer-son Laboratory Electron-Ion Collider (JLEIC) ion com-plex, the electron storage ring (e-ring) is consolidated to also serve as a large booster for the ions. The goal of reaching 16 GeV/u or higher for all ions using only room-temperature magnets forces the re-design of the e-ring because of magnetic field and lattice limitations. The new design is challenging due to several imposed constraints: (1) use of room-temperature magnets, (2) avoiding transi-tion crossing, and (3) maintaining the size and shape of the original e-ring design as much as possible. A design study is presented for a 16 GeV/u large ion booster after analyzing different alternatives that use: (1) combined-function magnets, (2) large quadrupoles or (3) quadrupole doublets in the lattice design. This design boosts the injection energy to the collider ring from 8 GeV (proton-equivalent) in the original baseline design to 16 GeV/u for all ions which is beneficial for the high-energy option of JLEIC of 200 GeV or higher. A scheme for adapting the new large ion booster design to also serve as electron storage ring is presented.
ANL, Lemont, Illinois, USA
Illinois Institute of Technology, Chicago, Illinois, USA
One of the requirements for the future Electron Ion Col-lider (EIC) is to collide polarized electrons and light ions with at least 70% polarization for each beam. For light ions, polarized ion sources are used for injection to a linac, which is usually the first accelerator in the collider chain. The Jefferson Lab EIC (JLEIC) ion injector linac consists of a low-energy room-temperature section with quadrupole focusing followed by a superconducting linac with solenoid focusing inside long cryomodules. These two sections have different effects on the spin. Spin dy-namics simulation studies are carried out for the JLEIC injector linac in order to preserve and maintain a high degree of polarization for light ion beams for delivery to the booster. The different options to maintain and restore the spin in the different sections of the linac for hydrogen, deuterium and helium ions are presented and discussed. Results from both the Zgoubi and COSY-Infinity codes are presented and compared for every section of the ion linac but the radio-frequency quadrupole (RFQ). Current-ly, a method to simulate the RFQ using Zgoubi is being investigated.