The Electron-Ion Collider (EIC) at Brookhaven National Laboratory will feature a 3.8-kilometer electron storage ring (ESR) that will circulate polarized beams with energies ranging from 5 to 18 GeV for collision with hadrons from a separate ring at luminosities up to 10^34 cm^{-2} s^{-1}. This contribution focuses on several recent changes to the lattice design of the ESR. Super-bend dipole triplets are used in the arc cells to increase the damping decrement and horizontal emittance at 5 GeV. Their lengths have recently been optimized to balance these two requirements. The interaction region has been modified to accommodate the requirements of a Compton polarimeter. Major changes have been made to IR8, which is the location of a possible second interaction region and detector that may be installed in a future upgrade. A design for a non-colliding IR8 has been developed that simplifies the setup to reduce initial costs and complexity. The latest lattice design of the ESR is presented here, and the major design choices are discussed.

We present an update on the design of the Interaction Region (IR) for the the Electron Ion Collider (EIC) being built at Brookhaven National Laboratory (BNL). The EIC will collide high energy and highly polarized hadron and electron beams with a center of mass energy up to 140 GeV with luminosities of up to 10^34 /cm^2/s. The IR, located at RHIC's IR6, is designed to meet the requirements of the nuclear physics community as outlined in [1]. A second IR is technically feasible but not part of the project. The magnet apertures are sufficiently large to allow desired collision products to reach the far-forward detectors; the electron magnet apertures in the rear direction are chosen to be large enough to pass the synchrotron radiation fan. In the forward direction the electron apertures are large enough for non-Gaussian tails. The paper discusses a number of recent recent changes to the design. The machine free region was recently increased from 9 to 9.5 m to allow for more space in the forward direction for the detector. The superconducting magnets on the forward side now operate at 1.9 K, which helps crosstalk and space issues.

Provisions are being made in the Electron Ion Collider (EIC) design for future installation of a second Interaction Region (IR), in addition to the day-one primary IR. The envisioned location for the second IR is the existing experimental hall at RHIC IP8. It is designed to work with the same beam energy combinations as the first IR, covering a full range of the center-of-mass energy of ~20 GeV to ~140 GeV. The goal of the second IR is to complement the first IR, and to improve the detection of scattered particles with magnetic rigidities similar to those of the ion beam. To achieve this, the second IR hadron beamline features a secondary focus in the forward ion direction. The design of the second IR is still evolving. This paper reports the current status of its parameters, magnet layout, and beam dynamics and discusses the ongoing improvements being made to ensure its optimal performance

One of the challenges of designing the Electron-Ion Collider (EIC) is to mitigate beam-induced heating due to the intense electron and hadron beams. Heating of the Electron Storage Ring (ESR) vacuum chamber components is mainly due to beam-induced resistive wall loss and synchrotron radiation. For the Hadron Storage Ring (HSR) components, heating is mainly due to resistive wall loss because of the large radial offset, electron cloud formation, and heat conduction from room temperature to cryo-components. In this paper, we provide an update on the beam-induced heating and thermal analysis for some EIC vacuum chamber components including the RF-fingers module of HSR cryogenic interconnect assembly. In addition, we provide simulation update for the HSR snake BPM, and abort kicker along with the change in ESR vacuum chamber profile. Similar analysis for other HSR and ESR components are available in Ref.~\cite{sangroulalocalized_NAPAC22, sangroula2023beam}. Our approach for thermal analysis involves calculating resistive wall losses using CST, evaluating heat loss due to synchrotron radiation and electron cloud formation and incorporating these losses into ANSYS for finding the temperature distribution.

A new high-luminosity Electron-Ion Collider (EIC) is being developed at BNL. Beam collisions occur at IP-6, involving two rings: the Electron Storage Ring (ESR) and the Hadron Storage Ring (HSR). The vacuum system of both rings is newly developed and impedance optimization is progressing. Beam-induced heating and thermal analysis are performed for both rings to manage and control thermal distribution. The study explores collective effects across the Rapid Cycling Synchrotron (RCS), ESR, and HSR using simulated single bunch wakefields. Discussions encompass impedance analysis, collective effects and beam interactions, and the impact of ion and electron clouds on beam dynamics.