The design of the electron-ion collider (EIC) at Brookhaven National Laboratory is well underway, aiming at a peak electron-proton luminosity of 10e+34 cm^-1·sec^-1. This high luminosity, the wide center-of-mass energy range from 29 to 141 GeV (e-p) and the high level of polarization require innovative solutions to maximize the performance of the machine, which makes the EIC one of the most challenging accelerator projects to date. The complexity of the EIC will be discussed, and the project status and plans will be presented.

Two distinct crab cavities are planned to compensate the luminosity loss of the 25 mrad crossing angle at the Electron Ion Collider (EIC) interaction point. The crab cavity systems being developed will operate at either 197 MHz or 394 MHz and the 197 MHz system will provide up to 11.5 MV of transverse voltage with up to 60 kW of fundamental mode power with a coaxial coupler. The 197 MHz crab cavity fields and high power transmission characteristics of the coaxial coupler require water cooling of the inner conductor. To introduce water into the inner conductor a coaxial tee with a quarter-wavelength stub is proposed with the water supply/return located at the zero voltage plane. This paper provides an overview of the current design, electromagnetic, thermal and structural analyses for the Quarter Wave Stub.

The Normal-Conducting Radio-Frequency (NCRF) systems for the Electron-Ion Collider Hadron Storage Ring (EIC HSR) consist of 4 unique cavity resonators. The HSR NCRF systems are composed of a 24.6 MHz capture and acceleration system, a combined 49.2 MHz and 98.4 MHz bunch splitting system, and a 197 MHz storage system for collider operations. This paper presents the preliminary design of the HSR NCRF systems. We describe the unique approach taken to optimize HSR performance while limiting the total number NCRF systems, reducing the NCRF systems contributions to the total HSR impedance while reducing operating complexity.

The Electron Ion Collider (EIC), to be built at BNL, is a unique high-energy, high-luminosity, polarized electron-proton/ion collider. High-Order-Mode (HOM) damping is a big challenge for EIC electron accelerators, especially for 17 single-cell 591 MHz SRF cavities in EIC Electron Storage Ring (ESR) because of its high electron beam current (up to 2.6 A). Room temperature SiC Beamline HOM absorbers (BLA) were chosen as the baseline of the HOM absorber, due to its broadband and high power capability. A SiC HOM absorber was prototyped to test a preparing process and high power handling capability. The high power test demonstrates 0.3 W/mm^2 of power handing capability by far, and we are going higher power to test its limit. This paper will present the preparing process (shrink fit, cleaning and outgassing test) and high power test results of the SIC HOM absorber prototype.

The Electron-Ion Collider (EIC) requires 34, 500 kW continuous-wave (cw), 591 MHz Fundamental Power Couplers (FPCs) to compensate the Electron Storage Ring’s (ESR) 10 MW of synchrotron radiation and other beam driven losses. This paper will describe the FPC design and fabrication status, particularly the technical challenges associated with 500 kW cw operation and the innovative design addressing this. Of important note, the RF window based on 99.5% purity alumina window was designed to be wide operating bandwidth, which makes it applicable to FPCs for the EIC’s RF systems outside of the ESR with frequencies ranging from 197 MHz-591 MHz. This results in significant savings by eliminating the need to design multiple different RF windows for the different RF systems. This paper will describe the design and prototype progress of the High Power FPC for EIC.

The electron storage ring (ESR) in the Electron Ion Collider (EIC) requires a challenging 591 MHz fundamental 17-cavity RF system to provide up to 10 MW CW power to the beam with up to 2.5 A beam current and a wide range of voltage. In this paper, we will report the latest RF and mechanical design status, as well as the prototyping and testing results.