Using a simplified multi spin resonances model we study the how the interference of spin resonances near a strong intrinsic spin resonance crossing effect the polarization transmission as a function of emittance for a lattice with more than two snakes.

Strong Hadron Cooling (SHC), utilizing the coherent electron cooling scheme, has been extensively investigated for the Electron Ion Collider (EIC). Throughout our cooling optimization studies, we realized that a Super-Gaussian electron bunch offers enhanced performance in comparison to a Gaussian bunch. Our approach involves initiating the electron beam distribution in a double peak form, transitioning them into a Super-Gaussian distribution due to the longitudinal space charge. Subsequently, a chicane within the linac section compresses the bunch to meet the required bunch length. We tuned a third harmonic cavity amplitude to reduce the nonlinear term of the chicane. Moreover, given the low initial current leading to a small but non-uniform slice energy spread, we evaluated utilizing laser heating techniques to achieve a uniformly distributed slice energy spread. In this report, we discuss the concepts and simulation results.

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.

The Electron-Ion Collider (EIC) plans to utilize the local crabbing crossing scheme. This paper explores the feasibility of adopting a single crab cavity with adjusted voltage, inspired by the successful global crabbing scheme in KEKB, to restore effective head-on collisions. Using weak-strong simulations, the study assesses the potential of this global crabbing scheme for the EIC while emphasizing the need for adiabatic cavity ramping to prevent luminosity loss. Additionally, the research outlines potential risks associated with beam dynamics in implementing this scheme.

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.

The Electron-Ion Collider (EIC) utilizes the existing Relativistic Heavy Ion Collider (RHIC) rings as a Hadron Storage Ring (HSR) with some modifications. However, this presents significant challenges, primarily due to beam-induced Resistive Wall (RW) heating resulting from a larger radial offset and shorter EIC bunches (up to 10 times shorter than RHIC). Additionally, the formation of an electron cloud further complicates matters. To address these issues and operate the HSR effectively, this paper focuses on the RW heating and thermal analysis of the EIC HSR beam screen. Our approach involves the insertion of a copper-coated stainless steel beam screen with cooling channels and longitudinal slots. We conducted a detailed thermal analysis, assessing piecewise RW losses around the beam screen's profile due to an offset beam, employing the 3D commercial code CST. These losses, along with realistic boundary conditions, were then integrated into another code, ANSYS, to determine the thermal distribution.

The Electron Ion Collider (EIC) Hadron Storage Ring (HSR) will reuse most of the existing hardware from the RHIC rings. However, extensive modifications will have to be performed in preparation for the new accelerator parameters and performance required by EIC. The beam vacuum chamber will have to be upgraded and new beam position monitors (BPM) implemented to account for the higher beam intensity and shorter EIC hadron bunches. The RF system will also need to be upgraded and include new cavities to drive the new bunch parameters. In some straight sections, existing superconducting magnets will have to be reshuffled and their cold powering scheme modified to accommodate the new accelerator lattice. The hadron injection scheme will also be modified to accommodate three time more bunches and the machine protection system will need to include new collimators. This paper aims to give an overview of the engineering modifications required to turn RHIC into the EIC HSR.

The Electron Ion Collider (EIC) hadron storage ring (HSR) requires a beam screen made of 75 μm copper layer on top of a 1 mm thick 316LN stainless steel sheet. The eddy currents produced by the dynamic fields at the beam screens of the transition jump quadrupoles will increase the field response delay. The field response curve depends on the thickness and Residual Resistivity Ratio (RRR) value of the copper layer. Manufacturing variances of thickness and RRR in the beam screens of the gamma transition quadrupole will result in different field response delays. This paper summarizes the effects from the beam screens on transition crossing. From the varying delays, the beta-wave and eta-wave may exceed typical RHIC values. The effectiveness of the jump will be estimated using simulations of the existing RHIC lattice.

At the CERN Large Hadron Collider (LHC), bent crystals play a crucial role in efficiently redirecting beam halo particles toward secondary collimators used for absorption. This innovative crystal collimation method leverages millimeter-sized crystals to achieve deflection equivalent to a magnetic field of hundreds of Tesla, significantly enhancing the machine’s cleaning performance particularly when running with heavy ion beams. Nevertheless, ensuring the continuous effectiveness of this process requires the optimal channeling angle with respect to the beam to be constantly maintained. The primary goal of this study is to improve the monitoring of crystal collimation by providing a tool that detects any deviations from the optimal channeling orientation. These deviations can arise from both crystal movement and fluctuations in beam dynamics. The ability to adapt and compensate for these changes is crucial for ensuring stable performance of crystal collimation during LHC operation. To achieve this, a feedforward neural network (FNN) was trained using data collected during the 2023 lead ion physics run at the LHC. The results demonstrate the network’s capability to supervise these crystal devices, accurately classifying when the crystal is optimally aligned with respect to the circulating beam. Furthermore, the model provides valuable insights into how to adjust the crystal’s position to restore optimal channeling conditions when required.

The LBNF Absorber consists of thirteen 6061-T6 aluminum core blocks. The core blocks are water cooled with de-ionized (DI) water which becomes radioactive during beam operations. The cooling water flows through gun-drilled channels in the core blocks. A weld quality optimization was performed to produce National Aeronautical Standard (NAS) 1514 Class I [1] quality welds on the aluminum core blocks. This was not successful in all cases. An existing Gas Tungsten Arc Welding (GTAW) Welding Procedure Specification (WPS) was fine tuned to minimize, in most cases, and eliminate detectable tungsten inclusions in the welds. All the weld coupons, how-ever passed welding inspection as per the piping code: ASME B31.3 Normal Fluid Service [2]. Tungsten electrode diameter, type, and manufacturer were varied. Some of the samples were pre-heated and others were not. It was observed that larger diameter electrodes, 5/32 in., with pre-heated joints resulted in welds with the least number of tungsten inclusions. It is hypothesized that thinner electrodes breakdown easily and get lodged into the weld pool during the welding process. This breakdown is further enhanced by the large temperature differential be-tween the un-preheated sample and the hot electrode.

Hadron therapy uses scanning magnets to precisely deliver therapeutic beams, minimizing the damage to healthy tissues and reducing side effects. A collaboration between CNAO, CERN, INFN and MedAustron is developing an innovative gantry design with superconducting magnets and a downstream scanning system. The project features two compact scanning dipoles, each with a central field of 1 T – about three times higher than current magnets used in clinical practice. The heightened magnetic field, together with the large rate of varying currents required for operation during treatments, prompts an investigation into non-linearities, necessitating a careful study of their impact on the performances of the system. This contribution provides insights into the dynamic behavior of a prototype scanning magnet with a FeCo yoke, with measurements of saturation, hysteretic effects, and eddy currents performed at Frascati National Laboratories, elucidating the feasibility of the proposed model. Additionally, in view of clinical implementation, the study explores methods of fast degaussing.

Various initiatives in Europe have been launched to study superconducting magnets for a rotatable gantry suitable to deliver up to 430 MeV/u carbon ions for hadron therapy. Different technologies and layouts are being considered: the baseline solution is developed within the EuroSIG collaboration and consists of a strongly curved cos-$\theta$ dipole based on the classical NbTi superconductor. The HITRIplus and I.FAST projects are dedicated to the study of the novel Canted Cosine Theta (CCT) dipoles based on NbTi and also HTS. Common design targets were set to allow a direct comparison of the different solutions: 4 T central field in an 80 mm bore, a curvature radius of 1.65 m, and a ramp rate of 0.15 – 0.4 T/s. The progress in the construction of four different demonstrator magnets is discussed and a preliminary comparison is proposed.

Designing the cryogenic BPM pick-up for the Hadron Storage Ring (HSR) of the Electron-Ion Collider (EIC) is a challenging task as it needs to provide reliable beam position measurements over a variety of beam species and operating modes with various energies. The existing RHIC BPM stripline pick-up are not compatible with the planned HSR beam parameters as the HSR beam, compared to RHIC, will have a factor of 10 shorter bunch length (to 6 cm rms), a factor of 3 more currents (0.69 Amps, with 290 bunches), and will have a large radial offset (±20 mm) to adjust the path length for different beam energies. The BPM pick-up design takes into consideration the potential elevated heating concerns caused by resistive wall loss due to radial beam offset and heat conduction through cryogenic BPM signal cables. The geometric impedance associated with the button configuration and housing transition to the adjacent HSR beam screen must also be minimized. This paper focuses on the design of the HSR cryogenic BPM pick-up and describes simulation results of the position-related voltage signals, and beam-induced losses on the metallic BPM buttons due to the radial offsets.

A new Rapid Cycling Synchrotron (RCS) [1] is designed to accelerate the electron bunches from 400 MeV up to 18 GeV for the Electron Ion Collider (EIC) [2] being built at Brookhaven National Laboratory (BNL). One of the two Relativistic Heavy Ion Collider (RHIC) rings will serve as the Hadron Storage Ring (HSR) of the EIC. Beam physics simulations for the RCS demonstrate that the electron beam is sensitive to the outside magnetic field in the tunnel. Significant magnetic fields are expected due to the HSR and the Electron Storage Ring (ESR) being at full energy during the RCS operation. The earth magnetic field at the location of the RCS center was measured throughout the circumference of 3870 m tunnel without RHIC operation. In addition, the fringe magnetic field from RHIC magnets at several locations during RHIC operation was measured and compared with simulation at different ramping currents. A robotic technology is being developed to automatically measure the stray magnetic field at any location during the RHIC (or future EIC) operation.

In order to prevent emittance growth during long stores of the proton beam at the future Electron-Ion Collider (EIC), we need to have some mechanism to provide fast cooling of the dense proton beams. One promising method is coherent electron cooling (CeC), which uses an electron beam to both ``measure'' the positions of protons within the bunch and then apply energy kicks which tend to reduce their longitudinal and transverse actions. In this work, we discuss the underlying physics of this process. We then discuss simulations which constrain the electrons to move only longitudinally in order to perform fast optimizations and long-term tracking of the bunch evolution, and benchmark these results against fully 3D codes. Additionally, we discuss practical challenges, including the necessity of a high-quality electron beam and sub-micron alignment of the electrons and protons.

The Electron-Ion Collider (EIC) is currently under development to be built at Brookhaven National Lab and requires cooling during collisions in order to preserve the quality of the hadron beam despite degradation due to intra-beam scattering and beam-beam effect. An Energy Recovery Linac (ERL) is being designed to deliver the necessary electron beam for Coherent electron Cooling (CeC) of the hadron beam, with an electron bunch charge of 1 nC and an average current of 100 mA; two modes of operation are being developed for 150 and 55 MeV electrons, corresponding to 275 and 100 GeV protons. The injector of this Strong Hadron Cooler ERL (SHC-ERL) is shared with the Precooler ERL, which cools lower energy proton beams via bunched beam cooling, as used in the Low Energy RHIC electron Cooling (LEReC). This paper reviews the current state of the design.