Technical challenges for forming the double intensity section of JLEIC ion beam Jiquan Guo

Options to form double intensity sections in JLEIC ion ring Interleaved transfer Circulating Bunches Abort Gap Circulating Bunches Second Injection Second Injection Bunch train transfer Kicker Gaps Andrew Hutton HL-LHC Collaboration Meeting Oct 2018

Using RF deflector to merge two beam Hutton, 2017 RF Separator with Superposed Magnetic Field Septum Magnet Recirculated Beam Injected Beam Injected Bunch Recirculated Bunch

Challenge for using ion RF merging at JLEIC: RF curvature The ion bunches are kept long due to space charge limit at merging energy Assuming 0.75A beam current, with 3584 bunches circulating (267ns gap, 267ns of 952MHz reprate, and the rest will be 476MHz reprate), and each bunch is cooled to 0.5µm normalized emittance, compressed to rms bunch length of 5.2cm or 1/6 of 952MHz bucket length, the Laslett tuneshift will hit 0.15 if the proton Ek is 15GeV Only 38% of particles are within ±0.5σ, 68% within ±1σ σz Injected Bunch Recirculated Bunch

Scaling of TW RF deflector power X-band (11.424GHz) TW deflector design examples by SLAC (J. Wang) Scaling to 476MHz 𝑟 ⊥ = 𝑄 𝑉 ⊥ 2 𝜔𝑈𝐿 ∝𝑄𝜔~8.5𝑀Ω/𝑚 𝑄∝ 𝜔 − 1 2 ~30000 𝑇 𝑓 =𝐿/ 𝑣 𝑔 L=4m, fill time ~420ns For const 𝑟 ⊥ TW structures, total kick 𝑉 ⊥ = 2𝑟 ⊥ 𝑃 0 2𝑄 𝑣 𝑔 𝜔 (1− 𝑒 − 𝜔𝐿 2𝑄𝑣 𝑔 ) To get 2mrad kick (RHIC uses 1.86mrad) at 15 GeV/c, 1mrad RF and 1mrad DC kicker, we need 15MV and 3.34MW (maybe a 1MW klystron + SLED, however the use of SLED will make the rise/fall sync of DC kicker and RF kicker much more difficult)