The Electron-Ion Collider (EIC), hosted by Brookhaven National Laboratory, is designed to deliver a peak luminosity of 1x 10(34) cm(-2)sec(-1). The interaction region (IR) of the EIC imposes several constraints in terms of field quality, aperture, and spatial layout, which necessitates the development of several unique superconducting serpentine direct wind magnets. These magnets are constructed using either a single strand or a small-diameter 6-around-1 NbTi cable, presenting unique challenges for design and optimization. This paper introduces a new computational code specifically developed to streamline and integrate the design process for these magnets, enabling faster design iterations while addressing their complex requirements. In this paper, we first introduce the code, which builds on established electromagnetic fundamentals. The code incorporates tools for optimizing winding patterns and for correcting magnetic multipoles; additionally, it interfaces with established magnet design software. We also present the design of several serpentine magnets for the EIC IR, demonstrating the code's capability to deliver precise and efficient solutions. These designs highlight the code's ability to accelerate the development cycle, ensuring the serpentine magnets meet the demanding specifications of the EIC project.

The electron ion collider (EIC) is under design to collide the high energy and highly polarized hadron with electron beams with luminosities up to 1034 cm-2s-1. The superconducting magnet designs at the interaction region (IR) are quite challenging due to the close proximity of the hadron and electron beams. Several serpentine types of superconducting magnets have been designed due to the space restrictions at the IR. To validate the designs in terms of the mechanical strength, structural integrity, as well as the allowed deformations, a detailed structural mechanical analysis for a 12-layer superconducting quadrupole serpentine magnet (Q1BpR) in the rear side hadron beams has been carried out using the finite element method (FEM) considering the pretension stress, shrinking due to cool down, and the electromagnetic force on the conductors. Anisotropy material properties and individual roving tension have been considered. The electro-magnetic (EM) simulations were performed using COMSOL, confirmed with RAT, the structural mechanical analysis were performed using COMSOL by considering the contact elements.

The Electron-Ion Collider (EIC), a new facility to be built in the United States at the U.S. Department of Energy's Brookhaven National Laboratory in collaboration with Thomas Jefferson National Accelerator Facility-will be the only new particle collider in the U.S. for the next 10 similar to 20 years. The EIC project will investigate the origin of mass and building blocks of the Universe. It will accelerate and collide beams of electrons with protons and nuclei. Unlike any collider that has ever existed before, both EIC's particle beams will be polarized, meaning their spins will be aligned in a controlled way to allow for precision measurements. Different types of new superconducting magnets will be required near the interaction region (IR) of EIC. A 6-around-1 NbTi cable will be used for some of those new superconducting magnets. Given the relatively smaller conductors used for those direct wind magnets, the overall engineering current density will be 2-3 times higher in comparison to traditional collared superconducting magnets in other accelerator magnets. This is technically challenging and potentially represents high risks for quench protection. In this paper we use different tools and methods for quench simulation for several EIC direct wind magnets. We also present results of a sensitivity study, exploring different material properties and Jc curves. This paper also discusses and validates the quench simulation results with measurement results from a small-scale serpentine magnet tested at BNL in October 2024.

The Electron-Ion Collider (EIC) is a proposed machine to explore the behaviour of the fundamental particles and forces that bind atomic nuclei together. The design and construction of the EIC are underway at Brookhaven National Laboratory in collaboration with Thomas Jefferson National Accelerator Facility. EIC will use several different types of superconducting strands for magnets near the interaction region (IR). At beam injection, the magnetic field is usually very low compared with its maximum operating field. This usually creates considerable field errors mainly generated from magnetization current in superconducting strands even using very fine filament. The accurate magnetization measurement results from those superconducting strands will be critical for the calculation and future correction of magnetic field for EIC. In this work, we characterized three billets of superconductor NbTi strands. The magnetization was measured at 4.2 K and 1.9 K in magnetic fields below 1.5 T. The critical current at 4.2 K and in magnetic field down to 5 T were also measured. Other properties that are important for the safety margin of superconducting magnet fabrication, operation, and quench protection such as residual-resistance-ratio (RRR), filament diameter, Cu to non-Cu ratio, twist pitch, and mechanical properties at 77 K will also be presented.

The Electron-Ion Collider (EIC) at Brookhaven National Laboratory (BNL) is designed to deliver a peak luminosity of 10(34) cm(-2)s(-1). An electron storage ring (ESR) will be installed in the existing Relativistic Heavy Ion Collider (RHIC) tunnel and will store polarized electron beams from 5 to 18 GeV. The ESR will have 750 dipole magnets with varying field requirements, including 576 super-bend triplets consisting of two magnets D1/D3 and D2. This paper presents on the engineering design of the D1/D3 dipole magnets within the arcs, with special focus on the coil design that allows the magnet to be configured for variable ampere-turns per energy.

The Electron-Ion Collider (EIC), a powerful new facility to be built in the United States at the U.S. Department of Energy's Brookhaven National Laboratory in collaboration with Thomas Jefferson National Accelerator Facility, will explore the most fundamental building blocks of nearly all visible matter. There are many different types of superconducting magnets near the interaction region (IR) of EIC. Due to space constraints and special lattice requirements, Tapered CCT (canted-cosine theta) magnets have been used for EIC. At beam injection, the magnetic field is only similar to 5.5% of the maximum operating field. Considerable field errors will be generated from persistent current in superconducting strands even using very fine filament for those superconductors. A tapered CCT demonstrator magnet has been built and tested successfully at BNL since July 2020 to evaluate the key technologies for future tapered CCT magnets. In October 2023, BNL team also measured the persistent current in this demonstrator magnet. To validate the persistent current simulation methods for CCT magnets in EIC, this paper used a full 3D Opera Model and measured magnetization data from superconducting strand for the simulation. Simulation results showed reasonable agreement with recent measurement results.

To avoid unacceptable proton emittance growth via beam-beam interaction, the EIC electron storage ring (ESR) requires very stringent tolerances for beam position and size stability at the interaction point. These tolerances imply tight specifications for several accelerator systems, including magnet power supplies (PS). While the magnetic field ripple requirements are most stringent at the betatron frequency and harmonics, the main PS challenges occur below ~1 kHz, where the ripple attenuation due to the vacuum chamber is insufficient. In the original ESR dipole powering scheme with ~20 families, the dipole PS current ripple specifications were found to be near or beyond the state-of-the-art. A recently adopted scheme with a single ESR main dipole PS relaxes these requirements to ~10 parts per million (ppm) rms, which is achievable. Additionally, the vacuum chambers of non-standard cross-sections required at some dipoles must be modified to match the field penetration time constant to that of the standard vacuum chamber. The paper presents the physics reasoning and simulations behind the latest PS ripple specifications, ranging from 5 to 100 ppm rms, depending on the magnet type.

Brookhaven National Laboratory is hosting the Electron Ion Collider (EIC). B1APF dipole is the last magnet near the interaction point #6. The longitudinal geometrical space available for this magnet is 1.5 m. The diameter of the coil mandrel is 370 mm. The 3-dimensional coil ends design is particularly challenging because of this large aspect ratio. The coil operating current and operating temperature are 12600 A and 1.9 K respectively. It produces an integrated dipole field of 4.05 Tm. The coil is wound with a NbTi Rutherford cable which is 15.1 mm wide and 1.8 mm thick. The parameters for the 3D end design optimization are obtained after a series of winding tests on a real mandrel with the given cable. This study discusses the latest design based on 1) sensitivity studies on variations in wedge thicknesses and variations in B-H data, and 2) experimental data from the winding trials, analysis and its implementation in the 3D design of this magnet.

The electron-ion collider (EIC), under design at Brookhaven National Laboratory, will consist of two storage rings for collisions of polarized electron and hadron beams. Dynamic aperture (DA) of 10 sigma is required in the electron storage ring (ESR) for the design beam energies from 5 GeV to 18 GeV to ensure an adequate beam lifetime. The DA is limited by chromatic and error effects in a strong optics with a low-beta interaction region. We present results of dynamic aperture studies for the latest ESR lattice (v6.3), which include compensation of non-linear chromaticity, the impact of field imperfections in dipoles, and the effects of dipole orbit.

The design of interaction region (IR) magnets for the Electron Ion Collider (EIC), demands tight boundary conditions on the magnet design given by the high field requirements and the proximity of electron and hadron beams within a common yoke and resultant crosstalk. This paper discusses the electromagnetic design of the superconducting collared magnet B1pF. The magnet will be built as the prototype for several collared magnets (dipoles and quadrupoles) for the hadron beam in the forward direction of the IR. The magnet design is based on a single layer coil with an inner diameter of 300 mm over a slot length of 3 m. The magnet produces an integral field of 10.34 T.m at a current of 11.9 kA to produce a nominal field of about 3.96 T at its center. Given by the common Rutherford cable parameters, the magnet will be used as a baseline for optimization of all the collared magnets. The paper further discusses yoke optimizations, quench analysis, coil end design and efforts on fine tuning of field quality.

Brookhaven National Laboratory has been chosen to host the Electron-Ion Collider (EIC). Part of this is to install an additional electron ring to the existing RHIC tunnel. The electron hadron Interaction Region (IR) will host nine superconducting magnets on the forward side and six superconducting magnets on the rear side of the Interaction Point (IP). B1APF dipole is the last magnet of the near IR in the outgoing hadron direction. The magnet has a physical aperture of 370 mm diameter and is 1.5 m long. This large aspect ratio makes this magnet particularly challenging. It is a collared magnet and uses a NbTi Rutherford cable with 15.1 mm X 1.9 mm. It is expected to operate at a maximum current of 13400 A at 2 K. The required integrated dipole field is 4.05 Tm. This paper discusses the current design status of the B1ApF dipole and presents the electromagnetic analysis and thermal quench propagation analysis.

A copper-clad stainless steel beam screen will be installed in each of the Relativistic Heavy Ion Collider (RHIC) superconducting (SC) magnets used for making the Electron-Ion Collider (EIC) Hadron Storage Ring (HSR). Eddy currents are induced within conductors to oppose a changing magnetic flux. Eddy currents will appear on the EIC HSR beam screens during ramp up and ramp down, after a magnet quenches and when reversing the polarity of the γ transition jump quadrupoles during γ transition crossing. This study evaluates the magnitude of the eddy currents, the temperature increase due to Joule heating and the stress at the beam screens from the eddy-current induced force.

The possibility of two interaction regions (IRs) is a design requirement for the Electron Ion Collider (the EIC). There is also a significant interest from the nuclear physics community in a 2nd IR with measurements capabilities complementary to those of the first IR. While the 2nd IR will be in operation over the entire energy range of ~20GeV to ~140GeV center of mass (CM). The 2nd IR can also provide an acceptance coverage complementary to that of the first. We present a brief overview and the current progress of the 2nd IR design in terms of the parameters, magnet layout, and beam dynamics.

The Electron-Ion Collider (EIC) is aiming at a design luminosity of 1 × 1034 cm−2sec−1 with collision with 10 GeV electrons and 275 GeV protons. To maintain such a high luminosity, both beams need an acceptable beam lifetime in presence of beam-beam interaction. For this purpose, we carried out weak-strong element-by-element particle tracking to evaluate the long-term dynamic aperture for the Hadron Storage Ring (HSR) lattice. We improved our simulation code SimTrack to treat some new lattice design features, such as crossing collision with crab cavities, a radially offset on-momentum orbits, etc. In this article, we present the preliminary dynamic aperture calculation results with crossing collision with crab cavities and magnetic field errors in interaction region.

The planned electron-ion collider (EIC) at Brookhaven National Laboratory (BNL) is designed to deliver a peak luminosity of 1×1034 cm−2sec−1. This paper presents an overview of the magnets required for the interaction region of the BNL EIC. To reduce risk and cost the IR is designed to employ conventional NbTi superconducting magnets. In the forward direction the magnets for the hadrons are required to pass a large neutron cone and particles with a transverse momentum of up to 1.3 GeV/c, which leads to large aperture requirements. In the rear direction the synchrotron radiation fan produced by the electron beam must not hit the magnet apertures, which determines their aperture. For the forward direction a mostly interleaved scheme is used for the optics, whereas for the rear side 2-in-1 magnets are employed. We present an overview of the EIC IR magnet design including the forward spectrometer magnet B0.