This work examines the multi-pass steering of six electron beams in an FFA arc ranging from approximately 10.5 GeV to 22 GeV. Shown here is an algorithm based on singular value decomposition (SVD) to successfully steer all six beams through the arc given precise knowledge of all beam positions at each of one hundred and one diagnostic locations with one hundred individual corrector magnets: that is successive application of SVD to different 100 × 101 response matrices—one for each beam energy. Further, a machine learning scheme is developed which only requires knowledge of the energy-averaged beam position at each location to provide equivalent steering. Extension of this scheme to other beam optics quantities as well as transverse and longitudinal coupling is explored.

A single wide-momentum-acceptance FFA beam line allows for recirculating a beam several times through a linac. Such a scheme provides an efficient path towards high-energy, high-power continuous beams. This paper describes the development of a conceptual design of an FFA RLA focusing on but not limited to a high-power hadron beam case. We present a complete optics design including arc, linac, and matching sections. The matching sections are implemented following the adiabatic approach whereby matching of all beam passes occurs simultaneously within a single beam line. Harmonic correction is applied for precise orbit and optics control of the individual passes. We discuss approaches to optimization of the linac timing and control of the longitudinal beam dynamics.

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 Continuous Electron Beam Accelerator Facility (CEBAF) is a 12 GeV recirculating electron accelerator at the Thomas Jefferson National Accelerator Facility (JLAB). Major upgrades to the accelerator are being investigated which include a new 650 MeV injection beamline and state-of-the-art fixed-field alternating (FFA) gradient recirculation arcs. The upgrade will extend the energy of the electron beam to over 20 GeV. In this paper, we provide an error and tolerance simulation study of the amended beam optics transport of the existing accelerator tuned for 22 GeV operation. The study is conducted with the particle tracking codes elegant and Bmad in two parts. In the first part, we treat each section of the accelerator (electromagnetic arcs and linacs) modularly with ideal conditions at the beginning. The second part is a pseudo start-to-end (S2E) simulation with accumulated errors propagating from one beamline to the next.

An upgrade to the Continuous Electron Beam Accelerator Facility (CEBAF) at the Thomas Jefferson National Accelerator Facility (JLAB) to extend its energy reach from 12 GeV to 22 GeV is being explored. The upgrade pushes the boundaries of the current CEBAF facilities and will require several state-of-the-art beamline components. The first of which is nonscaling Fixed Field Alternating (FFA) Gradient recirculation arcs, using novel Halbach-style permanent magnets. These new arcs would replace the current highest-energy recirculating arcs and allow up to six new beam passes spanning approximately a factor of two in energy. Matching into these arcs will require the design of splitter bend systems proceeding the north and south linac sections. Matching from these arcs into the proceeding linac section will be achieved using a novel transition section. Additionally, several major changes to the existing CEBAF accelerator will be implemented including a 650 MeV recirculating injector, a new multi-pass linac optics design based on a triplet focusing lattice, and a newly designed spreader/recombiner bend systems to accommodate the higher energy requirement.

This work examines the multi-pass steering of six electron beams in an FFA arc ranging from approximately 10.5 GeV to 22 GeV. Shown here is an algorithm based on singular value decomposition (SVD) to successfully steer all six beams through the arc given precise knowledge of all beam positions at each of one hundred and one diagnostic locations with one hundred individual corrector magnets: that is successive application of SVD to different 100 × 101 response matrices—one for each beam energy. Further, a machine learning scheme is developed which only requires knowledge of the energy-averaged beam position at each location to provide equivalent steering. Extension of this scheme to other beam optics quantities as well as transverse and longitudinal coupling is explored.

As Thomas Jefferson National Accelerator Facility (Jefferson Lab) looks toward the future, we are considering expanding our energy reach by using Fixed-Field Alternating Gradient (FFA) technology. Significant efforts have been made to design a hybrid accelerator which combines conventional recirculating electron LINAC design with permanent magnet-based FFA technology to increase the number of beam recirculations, and thus the energy. In an effort to further this progress, Jefferson Lab awarded a Laboratory Directed Research and Development (LDRD) grant to focus not on the design, but on detailed simulations of the designs created by the larger collaboration. This document will summarize the work performed during this LDRD, and direct the reader to other proceedings which describe elements of the work in greater detail.

The Electron-Ion Collider (EIC) Hadron Storage Ring (HSR) will use strong hadron cooling to maintain the beam brightness and high luminosity during long collision experiments. An Energy Recovery Linac is used to deliver the high-current high-brightness electron beam for cooling. For the best cooling effect, the electron beam requires low emittance, small energy spread, and uniform longitudinal distribution. In this work, we simulate and optimize the longitudinal laser-beam distribution shaping at the photo-cathode, modeling space charge forces accurately. Machine parameters such as RF cavity phases are optimized in conjunction with the beam distribution using a genetic optimizer. We demonstrate the improvement to the cooling distribution in key parameters.

The Electron-Ion Collider (EIC) is a cutting-edge accelerator designed to collide highly polarized electrons and ions. For enhanced luminosity, the ion beam is cooled via an electron beam sourced from an energy recovery linac (ERL). The current ERL design accommodates one RF cavity per cryomodule, presenting both beam transport and cost-related challenges. This study investigates the feasibility of reducing the cavity size to accommodate two cavities within a single cryomodule. We analyze two compact cavity design options through frequency scaling, assuming constant loaded quality factor Q and R/Q scaling proportional to the square of the frequency ratio. Our analytical and tracking Beam BreakUp (BBU) model predicts the threshold current for each option. While a smaller cavity footprint is advantageous, maintaining sufficient damping of Higher Order Modes (HOMs) is crucial. We compare the HOM damping effectiveness of the proposed compact design to the existing configuration, which achieves sufficient damping within a slightly larger footprint.

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.

Thomas Jefferson National Accelerator Facility (Jefferson Lab) currently studies the feasibility of upgrading its energy to 22GeV. It considers addition of six more linac passes. The highest energy passes will share two new arcs designed using the Fixed-Field Alternating Gradient (FFA) technology. The FFA arcs are built using permanent combined-function magnets. They will be connected to the linacs through transition sections that will match the optics of all six passes to the linacs. With the high number of constraints and the limited space available, we are investigating a parametric resonance technique to match the optics quasi-independently at each energy. A resonance is excited at each individual energy to selectively control its optics. The resonant dipole and quadrupole kick harmonics are imposed for all energies simultaneously using Panofsky corrector magnets placed throughout the FFA arcs. This paper presents the current progress on that transition section design.

Thomas Jefferson National Accelerator Facility (Jefferson Lab) is currently studying the feasibility of an energy upgrade based upon Fixed-Field Alternating Gradient (FFA) permanent magnet technology. The current plan is to replace the highest-energy recirculation arcs with FFA arcs, increasing the total number of beam recirculations, thus the energy. In order to accommodate multiple passes in the FFA arcs, horizontal splitters are being designed to control the beam parameters entering the FFA arcs, as well as time-of-flight and R56. In the current design, six passes will recirculate through the FFA arcs, necessitating the design of six independent beamlines to control the optics and beam dynamics matching into the arcs. These beamlines must fit into the current CEBAF tunnel while allowing for personnel and equipment access. They must also be flexible enough to accommodate the beam under realistic operational conditions and fluctuations. The constraints on the system are highly restrictive, complicating the design. This document will describe the current state of the design and indicate the work remaining for a complete conceptual design.

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.

The Continuous Electron Beam Accelerator Facility (CEBAF) is a 12 GeV recirculating electron accelerator at the Thomas Jefferson National Accelerator Facility (JLAB). Major upgrades to the accelerator are being investigated which include a new 650 MeV injection beamline and state-of-the-art fixed-field alternating (FFA) gradient recirculation arcs. The upgrade will extend the energy of the electron beam to over 20 GeV. In this paper, we provide an error and tolerance simulation study of the amended beam optics transport of the existing accelerator tuned for 22 GeV operation. The study is conducted with the particle tracking codes elegant and Bmad in two parts. In the first part, we treat each section of the accelerator (electromagnetic arcs and linacs) modularly with ideal conditions at the beginning. The second part is a pseudo start-to-end (S2E) simulation with accumulated errors propagating from one beamline to the next.

In late 2023, Thomas Jefferson National Accelerator Facility (Jefferson Lab) funded a Laboratory Directed Research and Development (LDRD) grant dedicated to investigating the impact of radiation on permanent magnet materials. This research initiative is specifically geared towards assessing materials slated for use in the CEBAF energy upgrade. The experimental approach involves strategically placing permanent magnet samples throughout the accelerator, exposing them to varying radiation doses. The simulation code BDSIM is used to first validate the data and then to simulate the effects on future higher energy passes to study the degradation effects on the permanent magnets. In this paper we present the progress of that work.

As the FFA@CEBAF energy upgrade study progresses, it is important to investigate the impact of radiation exposure on the permanent magnet materials to be used in the upgraded fixed field alternating gradient (FFA) arcs. To address this, Jefferson Lab has awarded a Laboratory Directed Research and Development (LDRD) grant to study the resiliency of several permanent magnet materials placed in a radiation environment similar to that in which they are expected to operate. Samples of NdFeB and SmCo are to be placed alongside appropriate dosimetry in a variety of radiation environments in the beam enclosure and experimental halls at CEBAF. The magnet degradation will be measured, and extrapolated to the higher energies expected during operations after the energy upgrade. This document will describe the current status of the LDRD study, as well as describe the upcoming plans. It will also direct the readers to other proceedings which further detail the work thus far.

This work is part of a larger program to study the effects of radiation on permanent magnets in an accelerator environment. In order to be sure that the permanent magnet samples are accurately placed, measured, and catalogued we have developed a system of sample racks, holders and measuring apparatuses. We have combined these holders and measurement racks with electronics to allow a single computer to catalogue the position and intensity of the magnet measurements. We outline the design of the apparatus, the collection software, and the methodology we will use to collect the data.