The International Linear Collider (ILC) requires crabbing system to compensate 14 mrad crossing angle. The crabbing system at 1.3 GHz needs to provide 1.845 MV crabbing voltage for 250 GeV case and 7.4 MV for 1 TeV case and needs to be fitted within 3.8 m allocated space. In this paper, a Wide-Open-Waveguide (WOW) type cavity is proposed as one of the candidates due to its simple structure and reasonable High Order Mode (HOM) damping.

Higher-order mode (HOM) damping is essential for building large-scale facility linear accelerators, such as a linear collider, because of the need to reduce the wakefield strength inside the accelerating structure. We designed a C-band accelerator cavity with distributed coupling and thin HOM-damping waveguides oriented in the radial direction. It was proposed that nickel-chrome (NiCr) coating deposited on the surface of the thin waveguides will be used to increase the surface resistivity and to damp the HOMs. Recently, we designed a two-cell cavity to conduct a concise high power test that will help us understand the fabrication challenges for the cavity with NiCr HOM absorbers, and examine the performance of the NiCr coating under high-power conditioning. This presentation will report the detailed electromagnetic and engineering design of the cavity, the theoretical prediction of the cavity high-gradient performance, the status of fabrication, and plans for high-gradient testing.

The Cool Copper Collider (C3) is a novel accelerator concept for a linear collider utilizing a cryogenically-cooled copper linear accelerator (linac) with a distributed coupling architecture. The C3 main linac is designed to accelerate electron/positron from 10 GeV to 125 GeV while preserving the beam emittance. Here we present the analysis of the multi-bunch beam dynamics for the C3 main linac. We show the beam dynamics simulation results of the C3 main linac to identify the frequency bands that cause emittance growth and the amount of frequency detuning required to suppress it. Results presented will be used to guide the future design of the accelerating structure.

The ATF2-3 beamline is the only facility in the world for testing the Final Focus Beamline of linear colliders and is essential for the ILC and the CLIC projects. A vertical electron beam size of 41 nm (within 10% of the target), a closed-loop intra-bunch feedback of latency 133 ns, and direct stabilization of the beam position at the Interaction Point to 41 nm (limited by IP BPM resolution) have all been achieved at ATF2. These results fulfilled the two main ATF2 design goals, but were obtained with reduced aberration optics and a bunch population of approximately 10% of the nominal value of 10^10 electrons. Recent studies indicate that the beam degradation with the beam intensity is due to the effects of wakefields. To overcome this intensity limitation, hardware upgrades including new vacuum chambers, magnets, IP-Beam Size Monitor laser, cavity BPMs, wakefield mitigation station, as well as a comprehensive R&D program to maximize the luminosity potential are being pursued in the framework of the ILC Technology Network. This new R&D program focuses on the study of wakefield mitigation techniques, correction of higher-order aberrations, tuning strategies, including AI techniques, as well as beam instrumentation issues, such as the BPMs, advanced Cherenkov Diffractive Radiation monitors, and fast feedback systems, among others. This paper summarizes the hardware upgrades, the R&D program and the results of the Fall 2023-Winter 2024 experimental campaign performed in ATF2-3.

Proton polarization is preserved in the AGS by using helical dipoles partial snakes to avoid depolarizing vertical resonances. These same helical dipoles also drive numerous (82) weak horizontal resonances that result in polarization loss. These horizontal resonances occur at the same energy (and therefore frequency) as depolarizing resonances driven by linear betatron coupling. A new scheme has therefore been implemented to correct the snake-driven resonances with the placement of skew quadrupoles in the AGS ring powered to cancel the resonance driving term at each horizontal resonance crossing. The skew quadrupoles are required to pulse independently for each resonance to account for the variation of drive term phasing with energy. Fifteen thin skew quadrupoles have been installed in the AGS ring to implement this correction. We describe the correction principle, the magnet design and commissioning results from RHIC Run 24.

The Rapid Cycling Synchrotron (RCS) of the Electron Ion Collider (EIC) will be used to accelerate polarized electrons from 400 MeV to a top energy of 5, 10, or 18 GeV before injecting into the Electron Storage Ring. At 1 GeV, the RCS will perform a merge of two bunches into one, adding longitudinal dynamics that effects the dynamic aperture, depending on the merge parameters. In this paper, results for different merge models will be compared, as well as finding the relationship between the merge parameters of the RCS and its dynamic aperture.

Beam profile measurements in the LHC and its injector complex show heavy tails in both transverse planes. From standard profile measurements, it is not possible to determine if the underlying phase space distribution is statistically independent. A measurement campaign in the CERN PSB was carried out to introduce cross-plane dependence in bunched beams in controlled conditions, in view of characterizing the LHC operational beam distributions. The results of the measurement campaign demonstrate how heavy tails can be created via coupled resonance excitation of the lattice in the presence of space charge, in accordance with predictions from the fixed line theory. The coupled resonance introduces dependence between the different planes, which persists after the resonance excitation is removed.

Despite a shorter-than-scheduled physics run due to a hardware problem, the AD/ELENA antiproton complex delivered record beam intensities to the experiments during the 2023 run. This paper reviews the performance of both the CERN Antiproton Decelerator (AD) and the Extra Low ENergy Antiproton (ELENA) decelerator and their associated transfer lines. It presents the main improvements that allowed these record beam intensities to be delivered to the experiments. Emphasis is put on the optimization of the injection line, progress made on the stochastic and electron cooling performance, increased deceleration efficiency and stability, and the software tools used. Remaining issues and potential future improvements for the coming run will also be presented.

The FNAL Booster is a fast cycling 15 Hz resonant circuit synchrotron accelerating proton beam from 400 MeV to 8 GeV. The linac pulse injected into the Booster is ~32 μsec long and fills the ring by multi-turn charge-exchange injection. As part of the PIP-II project, the Booster injection energy and repetition rate will be increased to 800 MeV and 20 Hz respectively. Due to much reduced average current in the new superconducting PIP-II linac, the injection time will increase to 550 μs. A shorter machine cycle coupled to a longer injection time make flattening the injection porch B-field during injection important requirement for successful PIP-II operation. We aim to achieve: (1) flattening of the net bending during injection using dipole correctors, and (2) using a new system based on an Altera FPGA board, reduction of the cycle-to-cycle bending field variation caused by current jitter in the Gradient Magnet Power Supply (GMPS). While the flat injection scheme is essential to future PIP-II operations, it should also noticeably improve efficiency for present HEP operations.

The J-PARC Main Ring accelerates proton beam from 3 GeV to 30 GeV and delivers it to T2K neutrino experiment with fast extraction and hadron experiments with slow extraction. In the last two years the beam power to the neutrino experiment was increased from 500 kW to 750 kW. The T2K detector is scheduled to be replaced by the new Hyper-K detector; the latter will be able to accept a 1.3 MW proton beam by 2028. To achieve 1.3 MW beam power, J-PARC plans to upgrade the Main Ring by increasing intensity and repetition rate. The Main Ring uses low frequency, high bandwidth RF cavities with Magnetic Alloy cores, powered by two 600 kW tetrode tubes. Under the upgrade plan, the number of RF cavities will be increased to secure the RF voltage and longitudinal acceptance. The anode power supply will be upgraded to provide enough current for both gap voltage and beam loading compensation. The upgraded LLRF system will be optimized to control fundamental and 2nd harmonic RF voltages, suppress coupled bunch instabilities and compensate beam loading effects. Current operational status as well as details of the upgrade plan and related simulation results will be discussed in this paper.

The design and study of the Circular Electron Positron Collider (CEPC) present a significant challenge, requiring the proper modeling of various physical phenomena such as the crab-waist collision scheme with a large Piwinski angle, strong nonlinear effects, energy sawtooth, beam-beam interactions, and machine impedances. In response to this challenge, the APES software project was proposed in 2021 and received support from the IHEP Innovative Fund in 2022. This paper provides an overview of the progress made in the APES project, encompassing modeling for special cases, orbital and spin tracking with synchrotron radiation, optics and emittance calculation, particle tracking, and more. Additionally, the paper discusses future developments.

The Korea fourth-generation storage ring (Korea-4GSR) project was launched in 2021 to generate high-brightness photon beams as a diffraction-limited light source. The 200 MeV beam is injected into the booster synchrotron. The beam parameters and transmission efficiency fluctuate with initial beam conditions such as beam Twiss parameters and centroid offsets during the injection and energy ramping process. Therefore, the study on the initial conditions of the incident beam to the booster synchrotron needs to be carried out to gain high beam quality and efficiency. This paper presents the energy ramping results of the beams injected into the booster synchrotron with various initial beam conditions.

The Advanced Light Source Upgrade (ALS-U) is a 4th generation diffraction-limited soft x-ray radiation source. Coupling-impedance-driven instabilities have been carefully evaluated to ensure meeting the machine’s high-performance goals during the design stage. At present, the focus of impedance modeling efforts primarily revolves around supporting beam tests of key components at ALS beamlines and the fabrication of various components. This paper presents impedance measurements of the main RF bellows with the Goubau-Line, as well as thermal evaluations on beam-induced heating on the RF bellows and the booster-to-accumulator ferrite (BTA) kicker on the ALS beamline. One challenge in the impedance modeling of the BTA kicker arises from a 4-micrometer-thick TiN coating, rendering direct modeling in CST challenging. To address this, we employed the ImpedanceWake2D (IW2D) code as an initial step to validate the efficacy of RF shielding. Subsequently, an equivalent model was constructed in CST to calculate the total impedance. We also show the impedance evaluation results and reduction strategies for the keyhole bellows and photon absorbers, incorporating thermal expansion considerations. Notably, the work is essential for successfully commissioning the ALS-U project.

In this paper, we delve into the application and comparative analysis of the Accelerator Physics Emulation System Cavity-Beam Interaction (APES_CBI) module within the BEPC-II (Beijing Electron-Positron Collider) experiments. We developed the APES_CBI module as an advanced time-domain solver, specifically designed to analyze RLC circuits driven by beam and generator currents and to simulate the dynamic responses and synchrotron oscillations of charged particles within the cavity. We begin by discussing our method for solving RLC parallel circuits, followed by an explanation of the logical architecture of our program. In the second part, we detailed our simulation results, starting with the BEPC-II electron ring. By comparing these results with experimental data, we validate the reliability of our simulations, showcasing our module's ability. Additionally, we extend our simulations to the CEPC Higgs mode on-axis injection conditions and studied the transient phase response to the sudden change of beam pattern.

CERN Proton Synchrotron (PS) is featured with 100 C-shaped combined-function Main Units (MUs) magnets with a complicated pole shape. The operation and the modelling of the PS-MUs has been historically carried out with empirical beam-based studies. However, it would be interesting to understand whether, starting from a proper magnetic model and using the predicted harmonics as input to optics simulations, it is possible to accurately predict the beam dynamics behavior in the PS, and assess the model accuracy with respect to beam-based measurements. To evaluate the magnetic model quality and its predictions, bare-machine configurations at different energies were prepared, where only the Main Coil is powered and the additional circuits are off. In this paper, a comparison of tunes and chromaticity measurements with the predicted optics is reported, showing the saturation of the quadrupolar and sextupolar components at high energy, which affect these quantities.

The strong hadron cooling system (SHC) for the electron-ion collider (EIC) consists of the modulator, the microbunching amplifier and the kicker section. In the modulator and the kicker section, the electrons are co-moving with the protons. If the relative velocity of an electron with respect to a proton is small enough, it can be captured by the proton and the resulting neutral particle, i.e. a hydrogen atom, will deviate from the designed trajectory and get lost around the cooling section. Since the probability of a proton capturing an electron depends on the relative velocity between them, one can align the energy of the two beams based on the number of hydrogen atoms detected by a recombination monitor. In this work, we estimate the rate at which the hydrogen atoms produced by the recombination process for the SHC in EIC.

Coherent electron cooling (CeC) is a novel technique for rapidly cooling high-energy, high-intensity hadron beam. Plasma cascade amplifier (PCA) has been proposed for the CeC experiment in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Cooling performance of PCA based CeC has been predicted in 3D start-to-end CeC simulations using code SPACE. The dependence of the cooling rate on the electron beam parameters has been explored in the simulation studies.

Electron cooling of ion beams employing RF-accelerated electron bunches was successfully used for the RHIC physics program in 2020 and 2021. Electron cooler LEReC uses a high-voltage photoemission electron gun with stringent requirements for beam current, beam quality, and stability. The electron gun has a photocathode with a high-power fiber laser, and a novel cathode production, transport, and exchange system. It has been demonstrated that the high-voltage photoemission gun can continually produce a high-current electron beam with a beam quality suitable for electron cooling. We describe the operational experience with the LEReC dc photoemission gun in RHIC and discuss the important aspects needed to achieve the required beam current, beam quality, and stability. We also present recent gun tests in which stable operation at 50 mA CW beam current was established, as well as future plans.

Muon colliders hold promise for high luminosity multi-TeV collisions, without synchrotron radiation challenges. However, this involves investigation into novel methods of muon production, acceleration, cooling, storage, and detection. Thus, a cooling demonstrator has been proposed to investigate 6D muon ionization cooling. The MICE experiment validated ionization cooling to reduce transverse emittance. The demonstrator will extend this to also cool longitudinal emittance. It would also use bunched beams instead of single particles from a muon source. The 6D cooling lattice comprises successive cells which consist of: solenoids for tight focusing, dipoles to introduce dispersion in the beam, wedge-shaped absorbers for differential beam absorption, and RF cavities for reacceleration. In this paper, the simulation and further optimization of the rectilinear cooling channel is discussed. This analysis extends existing theoretical and numerical work using BDSIM, a Geant4-based accelerator framework built to simulate the transport and interaction of particles. The study also incorporates beams from existing proton drivers, using output from targetry and capture designs for the same.

It is currently planned to increase the energy of the CEBAF recirculating linear accelerator to 20 GeV or more by adding two new recirculating arcs that contain multiple new energy passes. The beam is continuous (CW), so no field ramping is desired, making this a fixed-field accelerator (FFA). The wide energy range requires a low dispersion lattice that can be created with high-gradient permanent magnets. One constraint is the existing tunnel radius in relation to the fields achievable by practically-sized permanent magnets. Thus, searching for the most efficient implementation in terms of magnet material volume is important. In this paper, a lattice cell search and optimization is conducted that evaluates cells by the magnet volume per unit length, with the permanent magnet designs also produced via an automated code. The new lattice cells are compared to the previous manually designed cell.

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 2023 Particle Physics Project Prioritization Panel recommends an updated approach for accelerator R&D activities in the US research program. Key recommendations for the DOE-HEP General Accelerator R&D Program, a new targeted Collider R&D program, and the potential for increased engagement with the NSF are described.

The Fermilab Accelerator Science and Technology (FAST) facility is dedicated to the exploration of novel concepts in accelerator and beam physics, and the development of a robust workforce, in order to enable and enhance next-generation particle accelerators. FAST comprises a high-brightness superconducting electron linac, and a storage ring, the Integrable Optics Test Accelerator (IOTA). Experiments in the most recent operational run include studies of nonlinear integrable lattices; tracking of single electrons; precise characterization of undulator radiation; studies with low-momentum-compaction lattices; and ultra-wide range beam diagnostics based on Photomultiplier tubes. In the linac, experiments on noise in intense electron bunches were conducted. The IOTA proton injector, currently being commissioned, will enable a diverse program on space-charge-dominated beams. Research areas include non-invasive beam profile monitoring for proton beams; beam dynamics with electron lenses; halo suppression, feedback systems, and electron cooling. In this presentation, we provide an overview of the recent results and highlight future plans together with opportunities for collaboration.

Nanostructures are currently attracting attention as a medium for obtaining ultra-high-density plasmas for beam-driven or laser-driven acceleration. This study investigates Bayesian optimization in Laser Wakefield Acceleration (LWFA) to enhance solid-state plasma parameters towards achieving extremely high gradients on the order of TV/m or beyond, specifically focusing on nanostructured plasmas based on arrays of carbon nanotubes. Through Particle-In-Cell (PIC) simulations via EPOCH and custom Python scripts, we conducted a parameter analysis for various configurations of carbon nanotube arrays. Utilizing the open-source machine learning library BoTorch for optimization, our work resulted in a detailed database of simulation results. This enabled us to pinpoint optimal parameters for generating effective wakefields in these specialized plasmas. Ultimately, the results demonstrate that Bayesian optimization is an excellent tool for significantly refining parameter selection for nanostructures like carbon nanotube arrays, thus enabling the design of promising nanostructures for LWFA.

A very high electron peak current is needed in many applications of modern electron accelerators. To achieve this high current, a large energy chirp must be imposed on the bunch so that the electrons will compress when they pass through a chicane. In existing linear accelerators (LINACs), this energy chirp is imposed by accelerating the beam off-crest from the peak fields of the RF cavities, which increases the total length and power requirements of the LINAC. A novel concept known as the Transverse Deflecting Cavity Based Chirper (TCBC) [1] can be used to actively impose a large energy chirp onto an electron beam in an accelerator, without the need for off-crest acceleration. The TCBC consists of 3 transverse deflecting cavities, which together impose an energy chirp while cancelling out the transverse deflection. An experiment is being developed to demonstrate this concept at the Argonne Wakefield Accelerator (AWA) facility. Here we explain the concept, show preliminary simulations of the experiment, and report on progress related to implementation of the experiment at AWA.

A novel deuteron accelerator concept, the deuteron cyclotron auto-resonance accelerator (dCARA) is presented here, with (a) an analytical theory to characterize a simplified model for dCARA, (b) simulated tracks of deuteron orbits in a more realistic model for dCARA, and (c) CST-Studio particle-in-cell simulations for high-current deuteron beams in a realistic dCARA. These predict that dCARA will produce a high-current multi-MeV beam of accelerated deuterons along an axis parallel to, but displaced from, the center conductor of a coaxial resonator immersed in a uniform static magnetic field. The example presented, where the magnetic field strength is 7.0 T (for cyclotron auto-resonance at 53.0 MHz), acceleration of a 100 mA deuteron beam from 60 keV to 35 MeV is predicted to occur along a 2.8 m long half-wave resonant cavity, with an efficiency of 88%. Such a beam could be highly competitive with that produced either with linacs or cyclotrons for an application to produce, via deuteron stripping, a high flux of neutrons with an energy spectrum centered near 14.1 MeV, as needed for testing inner-wall materials for a future deuterium-tritium fusion power reactor.

I plan to discuss potential offered by Energy-Recovery Linacs (ERLs) and particle recycling for boosting luminosity in high-energy electron-positions and lepton-hadron colliders. ERL-based colliders have promise not only of significantly higher luminosity, but also of higher energy efficiency measured in units of luminosity divided by the consumed AC power. Addition of recycling collided particles and their recuperations in damping ring removes insane ILC/CLIC appetite for fresh positions and offers high degrees of polarization in colliding beams. Presentation will cover similarities and distinctions between linear and re-circulating ERL concepts with focus on their costs, energy efficiency and energy reach. Two examples of HIGS ERL-based factory located in LHC and FCC tunnels will be compared with two concepts of linear ERL colliders. Status of ERLs worldwide will be briefly review and technical challenges facing this promising accelerator technology will be discussed. I will finish talk with discussion of possible technical breakthroughs which can make ERL technology more affordable and more attractive.

We developed a magnetic compression method for relativistic electron beam macro-pulses. Our device, with a significantly larger transfer function R56 compared to the classical chicane structure, enables nanosecond-scale compression of relativistic electron pulses using a compact apparatus measuring just a few meters. This paper introduces the principles of this compression method and presents the results of dynamic simulations.

IFMIF-DONES is an ESFRI facility based on a 5 MW deuteron accelerator currently under construction in Granada (Spain) as part of the European roadmap to fusion electricity. Its main goal is to characterize and qualify materials under a neutron field with an induced damage like the one faced in a fusion reactor, developing a material database for the future fusion nuclear reactors. Moreover, a list of medium neutron flux experiments in other irradiation areas for fusion and non-fusion applications have been identified previously and are under analysis. The construction phase was officially launched from March 2023, after setting up the steering committee for the DONES Program composed of several countries. To support the preparation of the key documentation and consolidate contributions from parties, a set of tasks is being developed within the framework of the new DONES Consolidation Phase project (DONES-ConP1). In this contribution, the main objectives of the project such as the drafting of the acceptance tests for the procurement, the first version of the irradiation plan for fusion and non-fusion applications, or the update of key project documentation will be discussed.

The intensity of the HL-LHC beam will be twice that of LHC. Hence, an upgrade of the LHC injection kickers (MKIs) is necessary for HL-LHC to avoid excessive beam induced heating of the MKIs. In addition, any newly installed MKI magnet would limit HL-LHC operation for a few hundred hours due to dynamic vacuum activity. Extensive studies have been carried out to identify solutions to address these problems and they have been implemented in an upgraded LHC injection kicker magnet (MKI Cool): the MKI Cool was installed in the LHC during the 2022-23 Year End Technical Stop. Magnet heating has been reduced by redistributing a significant portion of the beam induced power deposition from the ferrite yoke to a ferrite loaded RF Damper, which is not at pulsed high voltage, and by water cooling of the damper. Furthermore, a surface coating, to mitigate dynamic vacuum activity, has been applied. This paper discusses the upgrades, presents results from the initial operational experience, and compares the predicted and ‘measured’ beam induced power deposition.

In the framework of the MYRRHA programme, a large-scale Accelerator Driven System (ADS) being implemented by SCK CEN in Belgium, a fast pulsed magnet system is being designed and specified at CERN. A complete design study has been performed to develop the specifications and drawings for a kicker magnet, as well as the associated pulse generator to deflect the 100 MeV proton beam. This paper outlines the numerical simulations that have been set up to evaluate the performance of the kicker magnet featuring a 5 μs rise time with a variable flat top of 10 μs to 500 μs and a 250 Hz repetition rate. The design study concluded on a water-cooled lumped inductance magnet with two half coils each of 2 turns featuring a magnet aperture of 90 mm x 57 mm. The outside vacuum magnet design requires a coated ceramic vacuum chamber to pass the fast kicker field of 17.3 mT. The associated pulse generator has been designed to deliver pulses of 2 kV and 200 A matching the kicker rise time and is outlined together with the cable choice.

The SPS injection kicker system comprises twelve MKP-S (small aperture) modules and four MKP-L (large aperture) modules. An upgraded MKP-L magnet was installed in the SPS, during December 2022, in view of the higher beam intensity needed in the future for High-Luminosity-LHC. The upgrades have significantly reduced the beam coupling impedance and consequent beam induced heating. The improved performance is due to a new beam screen, consisting of silver fingers painted on an alumina chamber, inserted in each magnet’s aperture. Additionally, a surface coating on the chamber's inner surface reduces its secondary electron yield and hence dynamic vacuum activity. The effectiveness of these upgrades was demonstrated during the 2023 operation. This paper provides an in-depth exploration of the initial year of operational experience with the upgraded MKP-L, giving a comparative analysis of dynamic vacuum and beam induced heating with the MKP-S modules. An alternative approach for upgrading the MKP-S modules, to reduce their temperature, is also proposed.

Fast single-turn injection kicker systems deflect incoming beam onto the orbit of the LHC. The higher intensities of High Luminosity (HL) LHC beams are predicted to cause the ferrite yokes of the LHC injection kicker magnets (MKI), in their current configuration, to heat up to their Curie temperature. Studies to reduce the beam induced heating have been carried out over the past years and resulted in a design featuring a water-cooled RF damper. A significant portion of the beam induced power has been relocated from the yoke to a ferrite in the RF damper. The ferrite damper is cooled via a copper sleeve, brazed to the ferrite, via a set of water pipes. The manufacturing of this RF damper system is challenging since different materials are brazed together to form a complex and fragile assembly, optimized for heat transfer, installed in an ultra-high vacuum environment. This paper outlines fabrication methods and their reproducibility, compares the results of measurements of the thermal interface between the ferrite and copper sleeve, and concludes on the challenges of assuring a production technique that results in a reliable and suitable thermal interface.

A central part of CERN’s Future Circular collider study (FCC) is a ~91 km circumference lepton collider and its injector complex. This contribution outlines the various kicker systems needed to transport the lepton beams from the electron source up to the collider dump system. The individual system requirements are presented, and the choice of design parameters and technology options for both, beamline elements and pulse generators are discussed. Potential challenges like the fast rise time of 50 ns for the damping ring kicker system working at 200 Hz repetition rate are highlighted, together with considerations on energy recovery. Ferrite loaded kicker magnet topologies are compared with system concepts employing strip lines. The paper concludes with a summary on the feasibility aspects and a recommendation for eventually needed prototype studies.

The PIP-II proton accelerator will provide the intensity sufficient to power a new generation of high energy facilities at Fermilab. Extension of that linac to higher energy with following acceleration and bunching rings could provide the intensity needed to feed a muon production target for a high-energy μ+-μ- collider. Scenarios using a rapid-cycling synchrotron or an ~8 GeV Linac are presented and discussed. Use of the existing Fermilab accelerators is also discussed. Support for other high-intensity experiments such as muon-ion collisions, neutrino sources and lepton flavor conservation is also considered.

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 proposed ten-pass energy recovery linac (ERL) demonstration (five accelerating, five decelerating) at the CEBAF accelerator, ER@CEBAF, involves a multi-GeV energy range of a continuous electron beam. New CEBAF transverse optics were designed for this ERL demonstration. This redesign incorporates additional components in Arc A, including a path length chicane and new quadrupoles to ensure proper dispersion localization. The new five energy recovery passes with a shared arc transport scheme challenge the overall beamline optics design, including large beta functions in the CEBAF spreaders and recombiners. Here we discuss results of bunch tracking performed using the elegant tracking code for the full ER@CEBAF beamline.

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.

The BEam COoler and LAser spectroscopy (BECOLA) is a collinear laser spectroscopy facility at the Facility for Rare Isotope Beams (FRIB) at Michigan State University. Time resolved laser spectroscopy experiments are performed here to study the nuclear structure of radioactive isotopes. The current data acquisition (DAQ) system being used is based on AMD Spartan 6 field programmable gate array (FPGA) and has a time resolution of 8 ns. There was a need to upgrade existing hardware to meet the requirements for higher time resolution of fast ion detectors. A new DAQ system with AMD Zynq System on Chip (SoC) FPGA based time-resolved scaler was designed, developed and fabricated. It achieves a time resolution of 2 ns. The current amplifier-discriminator has an output pulse resolution of 10 ns. To address this constraint and fully leverage the 2 ns time resolution provided by the new SoC FPGA, a new AD with an output pulse resolution of 1 ns was designed. A brief overview of the upgraded DAQ system will be discussed in this paper, including its features, improvements and future updates.

In accelerator physics, channeling is a well-established phenomenon. By carefully selecting crystal orientation, particle’s trajectories can be controlled and guided along desired paths. Bent crystals have been used at worldwide particle accelerators as optical elements to steer charged particle beams, with an elective application related to the collimation of the lead ion beam circulating in the large hadron collider (LHC) at CERN. This result opens new possibilities for innovative experimental setups, allowing for example to realize fixed target experiments at the TeV scale energy. Such experiments require compact, and light bent crystals with a length along the beam in the range of few cm and extremely uniform radius of curvature. An innovative method of crafting bent crystal for this class of experiments relies on anodic bonding of silicon to pre-figured glass. The presented methodology has potential to open new possibilities for optimizing beam quality and beam extraction in particle accelerators, leading to innovative physics experiments.

Positron source yield is a key factor for reaching the luminosity needed in future lepton colliders. Conventional scheme relies on a few GeV e-beam impacting on a high-density solid target to initiate an e.m. shower and collect the positrons after the target. This scheme is limited by the maximum heat load on the target before its structural failure. An innovative approach to overcome such limitations exploits the large photon emission in axial channeling in a crystal radiator, to increase the positron yield and/or decrease the target thickness and therefore the Peak Energy Deposited Density in it*. Together with the conventional scheme, our crystal-based one is under study for the FCC-ee injector design**. We carried out experiments at DESY and CERN PS with high-Z crystals (W and Ir) and tuned e-beam parameters useful for FCC-ee to validate a new simulation model implemented in Geant4***. This model includes the modified photon production in channeling condition and oriented crystals in general. Capable of designing the full FCC-ee source. This new model was employed to simulate the positron source showing reduced energy deposition compared to conventional sources.

The PSI Positron Production experiment, known as P\textsuperscript{3} or \textit{P-cubed}, is a proof-of-principle positron source and capture system that can greatly improve the state-of-the-art positron yield. The P\textsuperscript{3} project is led by the Paul Scherrer Institute in Switzerland, and addresses the long-standing challenge faced by conventional injector facilities to generate, capture, and damp the emittance of high-current positron beam, which is a major limiting factor for the feasibility of future electron-positron colliders. P\textsuperscript{3} follows the same basic principles as its predecessors, utilizing a positron source driven by pair-production and an RF linac with a high-field solenoid focusing system. However, it incorporates pioneering technology, such as high-temperature superconducting solenoids, that can outperform significantly the present positron capture efficiency rates. The P\textsuperscript{3} experiment will be hosted at PSI's SwissFEL, and will serve as the positron source test facility of CERN's FCC-ee. This paper outlines the concept, technology, infrastructure, physics studies and diagnostics of P\textsuperscript{3}.

The East Area at the Proton Synchrotron has undergone extensive renovations, marking a significant milestone in its more than 55-year history as one of CERN’s enduring facilities for experiments, beam tests, and irradiation. This facility, which serves over 20 user teams for about 200 days annually, now boasts an enhanced infrastructure to cater to future beam test and physics requirements. It also features new beam optics that ensure a better transmission and purity of the secondary beams, with the addition of pure electron, hadron, and muon beams. With this contribution, we present the ongoing performance studies underway following the implementation of the East Area secondary beamlines in the BDSIM (Beam Delivery Simulation) Monte Carlo simulation software. Using BDSIM, the impact on the transmission, purity, and overall efficiency of the secondary beams is assessed to the measured performance, paving the way for possible additional modifications and/or further upgrades.

The Electron Ion Collider calls for polarized proton and helion beams on polarized electron beam collisions. To preserve polarization of polarized hadron beams, six full helical snakes will be installed. As there are currently 4 snakes in RHIC, the remaining two snakes will be made from existing rotator magnet coils. The rotator magnets are made from both right handed and left handed helicities. In order for a sufficient stock of spare coils, one snake will be made of left handed coils. Simulations using zgoubi show the left handed snake has sufficient range to provide the desired snake precession axes for helions and protons with the existing power supplies.

The strength of a first-order spin-orbit resonance is defined as the amplitude of the corresponding Fourier component of the spin-precession vector. However, it is possible to obtain the resonance strength without computing the Fourier integral directly. If a resonance is sufficiently strong, then to a good approximation, one can neglect all other depolarizing effects when near the resonance. Such an approximation leads to the single resonance model (SRM), for which many aspects of spin motion are analytically solvable. In this paper, we calculate the strength of first-order resonances using various formulae derived from the SRM, utilizing spin tracking data, the direction of the invariant spin field, and jumps in the amplitude-dependent spin tune. Examples are drawn from the RHIC Blue ring.

“Three-dimensional spiral beam injection scheme” [1] is a key to realize J-PARC muon g-2/EDM experiment exploring the beyond standard model of elementary physics. Muon is stored in a compact orbit of 0.33 m radius in the super conducting solenoid storage magnet. Appropriate X-Y coupled beam phase space, which strongly coupled radial and solenoid axes, is crucial to inject the beam passing through the static solenoid fringe field. Vertical kicker [2] is also crucial to stabilize beam motion in the storage ring. In this report, results from the validation experiment [3] which utilize 80 keV electron beam and super compact storage ring with 0.12 m radius orbit are discussed: how well we do with (1) extended Twiss parameters for X-Y coupled beam in accordance with parameter weighting priority, (2) evaluate four-dimensional sigma-matrix of such strongly X-Y coupled beam phase space, (3) control the beam size during the injection, especially along the solenoid-axis. Utilizing several beam diagnostic methods in the storage volume (beam visualization monitor, wire-scan system), we discuss comparison between design and real data, and judge strategic robustness.

The proton storage ring (PSR) upgrade for the LANSCE Modernization Project aims to minimize the yearly maintenance outage by minimizing beam loss. Several improvements could potentially impact the beam dynamics in the PSR, including a larger coated beam pipe and new buncher, injection, and extraction systems. The larger diameter, from 4” to 6”, will directly impact the beam dynamics due to an increased pole-to-pole gap height within the dipoles and quadrupoles, which would in turn increase their effective length and alter their fringe field profiles. In this work, a simulation model of the PSR ring was developed using the particle tracking code pyORBIT to study the effect of different beam pipe diameters on the beam optics. The parameters of the injected beam are derived from an existing model of the PSR injection system, and the resulting beam parameters will be used in a simulation model of the extraction system, to be presented separately at the conference. The pyORBIT results were benchmarked against beam optics simulations created using accelerator codes including MAD-X, etc. The pyORBIT simulation model of the PSR ring will be described, and the results will be presented at the conference.

In the storage rings, the electron beams go to the equilibrium state. One of the equilibrium parameters is the natural emittance which is determined by the radiation damping and quantum excitation effects. In other words, the equilibrium emittance is determined by the magnet lattice regardless of the initial beam. Theoretically the minimum emittance and its optimal conditions for uniform bending magnet have been well demonstrated. However, the minimum condition doesn't include the damping partition number. In this paper, we tried to calculate the minimum emittance including the damping partition number. The results shows that the minimum emittance condition and the minimum emittance value is slightly changed by including the damping partition number.

In this study, we present a lattice design for the dif-fraction limited storage ring (DLSR), achieving an ultra-low natural emittance of 25.6 pm·rad (N-IBS). To address the significant intra-beam scattering (IBS) effect resulting from the ultra-low emittance and long damping times, Horizontal Field Damping Wigglers (HFDWs) have been adopted. These components de-crease damping times and beam horizontal emittance while generating vertical emittance, thereby achieving a "round beam" in the 864mDLSR. Using theoretical analysis and accelerator toolbox simulations, the op-timal peak field, period length, and overall length of the HFDWs for the 864mDLSR have been determined. In addition, the linear optical corrections were per-formed on both the front and rear units of the HFDWs using six quadrupoles.

Super-NaNu is a proposed neutrino experiment as part of the SHADOWS proposal for the high intensity facility ECN3 in CERN's North Area. It aims to detect neutrino interactions downstream of a beam-dump that is penetrated with a 400 GeV high intensity proton beam from the SPS. The experiment would run in parallel to the HIKE and SHADOWS experiments, taking data with an emulsion detector. Simulations show that various combinations of muon backgrounds pose the major limiting component for NaNu operation. As muons will leave tracks in the emulsion detector, their flux at the detector location is directly correlated to the frequency of emulation exchange and therefore with the cost of the experiment. Finding ways of mitigating the muon background as much as possible is therefore essential. In this paper, we present a possible mitigation strategy for muon backgrounds.

A double-crystal fixed-target experiment is planned for installation in CERN’s Large Hadron Collider (LHC). This experiment features a 7 cm-long bent silicon crystal, with 7 mrad bend-angle to deflect particles produced by proton interactions with a target. As this crystal is more than an order of magnitude longer than any other installed in the LHC, it requires specific characterization, alignment, and testing. Testing will begin using the LHC’s proton beam at different beam energies, before considering studies of interactions with particles out scattered from a target. Using a particle tracking program, we simulate the expected signals from the angular alignment of this unique crystal with multi-turn halo particles of the circulating LHC proton beam. A range of beam energies is considered to evaluate the performance, as particles with a spread of energies are anticipated downstream of the target following the interactions of the 7 TeV proton beams in the final experiment. The simulation results predict the crystal’s multi-turn efficiency as a function of energy and serve as a benchmark for the commissioning process to integrate this long crystal into the LHC.

A novel double-crystal experiment is being considered for installation in CERN’s Large Hadron Collider (LHC) to measure precession properties of short-lived baryons such as the Λc+. The experiment utilises a first bent silicon crystal of 50 µrad to deflect halo particles away from the circulating proton beam. Further downstream, a second crystal is installed, which produces a significantly greater bending angle of 7 mrad. While the former is well understood in simulations and measurements, the latter presents a new challenge for existing simulation tools. Using particle tracking programs, SixTrack and the newly developed Xsuite, we simulate a single pass experiment to calculate the expected channelling efficiency of these crystals. The results serve as a prediction for the performance of prototype crystals recently tested in CERN’s North Experimental Area at 180 GeV, and that are planned to be installed in the LHC in 2025 for use in the multi-TeV energy range.

The Future Circular Collider (FCC) study foresees the construction of a 90.7 km underground ring where, as a first stage, a high-luminosity electron-positron collider (FCC-ee) is envisaged, operating at beam energies from 45.6 GeV (Z pole) to 182.5 GeV (ttbar). In the FCC-ee experimental interaction regions, various physical processes give rise to particle showers that can be detrimental to machine components as well as equipment in the tunnel, such as cables and electronics. In this work, we evaluate the impact of the synchrotron radiation (SR) emitted in the magnets and the beamstrahlung (BS) radiation from the interaction point (IP). The Monte Carlo code FLUKA is used to quantify the power deposited in key machine elements, such as the BS dump, as well as the cumulative radiation levels in the tunnel. We also examine the effect of SR absorbers in the vacuum chamber and of external tungsten shielding. The results are presented for the different operation modes, namely Z pole and ttbar.

In this paper we discuss the latest developments for the FCC-ee interaction region layout, which represents one of the key ingredients to establish the feasibility of the FCC-ee. The collider has to achieve extremely high luminosities over a wide range of center-of-mass energies with two or four interaction points. The complex final focus hosted in the detector region has to be carefully designed, and the impact of beam losses and of any type of synchrotron radiation generated in the interaction region, including beamstrahlung, have to be evaluated in detail with simulations. We give an overview of the progress of the whole machine-detector-interface-related studies, among which are the updated mechanical model of the interaction region, the plans for a novel R&D activity of a IR mockup which is just starting, the collimation scheme and evaluation of beam induced backgrounds in the detectors, evaluation of radiation dose in the experimental area, and MDI integration with the detector.

We present the optics design of the solenoid compensation scheme at the FCC-ee. The 2T solenoids from the experiments induce coupling on the beams, generating an increase on vertical emittance. This compensation scheme minimizes emittance growth, with a final value of approximately 5% of the nominal.
 A screening solenoid is placed around the Final Focus Quadrupoles to protect them from the experiment’s field. 
A skew quadrupole component is added to the Final Doublet, aligning the magnet axis to the rotated reference frame of the beam. 
Two anti-solenoids placed approximately ±20 m from the IP are used to cancel the field integral. The vertical orbit generated by the horizontal crossing angle in the detector field is compensated by vertical correctors placed right after the beam pipe separation and next to the final focus quadrupoles.
 We describe the IR optics in this scheme, including the detector solenoid and the magnetic elements used for compensation.

Slow resonant extraction plays a crucial role in delivering a high-quality continuous beam to experiments. Simulating extraction and transport of charged particle beams require a process of careful modeling and experimentation. There are various particle tracking simulation tools available to use. Each has its merits and deficiencies. In this work we have used long-term tracking based on the Bmad toolkit to run third integer resonant extraction simulations of beams of various ion species in the booster synchrotron at Brookhaven National Laboratory. In this paper, we will present results of detailed slow extraction, multi-particle tracking simulations, and we will describe the features that make Bmad a useful tool for this work. We will show comparisons to other simulation tools of our results.

In 2023, an RF technique known as empty-bucket channelling was implemented operationally at the CERN Super Proton Synchrotron (SPS) to improve the quality of the spill provided to the North Area experiments. Empty-bucket channelling suppresses particle-flux variations during resonant slow extraction by accelerating particles between empty RF buckets and rapidly displacing particles into the tune resonance via chromatic coupling. The flux variations are often caused by the power converter ripple present in the synchrotron’s magnets, which modulates the beam dynamics during the extraction process. In a chromatic extraction, the quadrupole ripple is the main contribution to the modulation as it directly perturbs the transverse tune. When empty-bucket channelling is applied, however, dipole ripple additionally modulates the size of the empty RF bucket. In this contribution, the phenomenon is explored and the consequences for empty bucket channelling in the SPS are outlined.

The High Intensity ECN3 (HI-ECN3) study project aims to increase the intensity of the proton beam delivered to a new experimental facility housed in the ECN3 underground cavern in CERN’s North Area up to the ~4e+13 ppp (protons per pulse) and up to ~4e+19 POT (protons on target) per year. The increase necessitates upgrades of the primary beam transfer lines coming from SPS directly to the new Target Complex upstream of ECN3. In this work we describe the modifications to the primary beam line optics that allow the transfer of the beam to the HI-ECN3 facility in two scenarios: shared (beam is split between the three existing production targets) and dedicated (beam goes directly to the target serving ECN3). An optimization study is presented to reduce the sensitivity of the beam optics to errors and minimize the effects of the beam’s interaction with material when transiting the existing target area between TT24 and P42, whilst respecting the different constraints needed to share the beam between ECN3 and the rest of the North Area and permit a vertical trajectory bump around the target serving EHN1.

The impact of high-flux protons on the inherent beam loss in the slow extraction from SPS towards the North Area has been recently discussed and potential improvements have been proposed. These solutions are mainly aiming to reduce the high component activation and related reduction of lifetime, as well as observed non straightness in the anode body. Recent studies have allowed to demonstrate feasibility of replacing the currently installed stainless steel tank, flanges, and anode body by lowZ materials. The design iteration and material choice has led to the fabrication of a reduced length prototype, demonstrating mechanical, electrical, as well as the vacuum related performance. The mass reduction of the anode body has been optimized using numerical simulation, considering mechanical and thermal constraints. The paper presents the development of the vacuum vessel, including numerical analysis. The results from the design and prototype tank fabrication will be compared to the existing system. Furthermore, the optimization of the anode body and potential fabrication based on additive manufacturing including 3d optical straightness metrology will be discussed.

The P42 beamline transports 400 GeV protons from the CERN SPS between the T4 and T10 targets. A secondary particle beam is produced at the T10 target and transported along the K12 beamline to the experimental cavern ECN3, presently housing the NA62 experiment. In the context of the Physics Beyond Colliders (PBC) study, an increase of the beam intensity in P42 has been considered to provide protons to a future high-intensity fixed-target experiment in ECN3. For both its present usage and especially for the intensity upgrade, it is important to reduce beam losses to a minimum to decrease environmental radiation levels and protect equipment. In this study, simulations of P42 with the Monte Carlo software BDSIM, are used to demonstrate that beam losses in P42 are primarily driven by particle-matter interactions in material intercepted by the beam. The distribution of the simulated losses is compared to doses measured along the beamline in radioprotection surveys and beam loss monitors. Future mitigation strategies to reduce beam losses are then discussed and evaluated.

400 GeV protons extracted from the CERN SPS are transported to the T4 target via the TT20 transfer line. The P42 beamline then transports the protons that did not interact in the T4 target to the T10 target. During operation in 2021 and 2022, higher than expected beam losses were measured, in addition to an increased beam spot size that had previously been observed. It was suspected that the optics between TT24 and P42 might not be well matched but due to a lack of instrumentation this was not confirmed. The recent installation of additional beam profile monitors (BSG) in the P42 beamline has allowed the present optics to be evaluated for the first time. In addition, magnet response functions have been measured and updated. A kick response study was performed using corrector dipoles to kick the beam with the subsequent displacement measured on the BSGs. The dependence between the kick and the beam position was used to fit a MADX optics model of TT24 and P42. Quadrupole scans were then performed to determine the initial conditions of the model. These results are presented in this paper.

In view of High Luminosity (HL) - Large Hadron Collider (LHC) project, an upgraded collimation system has been developed to accommodate a rise of ten times of the integrated luminosity compared to the LHC. A new series of collimators will be produced and installed in the machine during the Long Shutdown 3 (LS3) to take place during 2026-2028. The updated design incorporates cutting-edge technologies to meet the demanding operating requirements. Multiple production activities are recognized as critical to ensure the quality of the collimators. Comprehensive qualification checks of the production procedures are planned, and functional tests will be conducted to validate the performance of each unit produced.

The Future Circular electron-positron Collider, FCC-ee, is a design study for a 90 km circumference luminosity-frontier and highest-energy e+e- collider. It foresees four operation modes optimized for producing different particles by colliding high-brightness lepton beams. Operating such a machine presents unique challenges, including stored beam energies up to 17.5 MJ, a value about two orders of magnitude higher than any lepton collider to date. Given the high stored beam energy, unavoidable beam losses pose a serious risk of damage. Thus, an adequate protection system has to be implemented. To address this challenge, a beam collimation system to protect the sensitive equipment of this machine is indispensable. This paper presents the studies that led to a new collimation system baseline and a collimation performance evaluation under selected beam loss scenarios.

The alignment installation work of Hefei Advanced Light Facility (HALF) is usually carried out in tunnels. Calculate the key component points to the global coor-dinate system through coordinate conversion, and accu-rately adjust them to the corresponding coordinate values for alignment and installation. However, long and narrow tunnels can easily cause dense common points, resulting in a loss of accuracy. Therefore, to quickly and accurately obtain the coordinate transformation parameters, this article proposes a common point selection method with uniformity normalization and selects the optimal com-mon points set based on the normalized uniformity in different directions. The feasibility of this method was verified based on experimental data. The results show that the conversion parameters solved by this method are more accurate, avoiding accuracy loss due to aggregation in a certain direction, and are suitable for long and narrow tunnels.

We will present the plans and ideas for the next upgrades as discussed for the GANIL-SPIRAL2 installation in France. Recently, a report "French roadmap for Nuclear, Particle, and Astroparticle physics, along with associated technical developments and applications." were produced. It particularly focused to “The future of GANIL”. This was further enriched through extensive discussions by an international expert committee led by Michel SPIRO. These endeavors aim to push the boundaries of research capabilities at GANIL-SPIRAL2 during the next decades. Since the starting up in 1983, 40 years ago, successful exploitation with stable beams at the cyclotrons of GANIL, the laboratory has continuously evaluated and enhanced its capabilities. The latest evolution was the starting up of the SPIRAL2 facility. Today GANIL, with its state-of-the-art installations, including cyclotrons, a linear accelerator, and experimental areas, presents unique opportunities for cutting-edge research. The next upgrades under discussion are to be presented. Involving increasing beam intensities, exploring new exotic nuclei. Endeavors that aim to push the boundaries of research capabilities at GANIL-SPIRAL2 for the next decades.

The Physics Beyond Colliders is a CERN exploratory study aimed to fully exploit the scientific potential of its accelerator complex. In this initiative, the Gamma Factory experiment aims to produce in the Large Hadron Collider (GF@LHC) high-intensity photon beams in the energy domain up to 400 MeV. The production scheme is based on the collisions of a laser with ultra-relativistic atomic beam of Partially Stripped Ions (PSI) circulating in a storage ring. The collision results in a resonant excitation of the atoms, followed by the spontaneous emission of high-energy photons. A Proof of Principle (PoP) experiment is being planned to study the GF scheme generating X-rays, in the range of keV, from lithium-like lead PSI stored at the CERN Super Proton Synchrotron (SPS). GF-PoP has undergone a series of exhaustive radiation effect studies in view of Radiation to Electronics (R2E) risks. With the use of FLUKA Monte Carlo code, the radiation environment in the laser room and its premises has been estimated during proton and PSI runs. Recorded data from beam instruments has been used to appropriately scale the computed results and to verify the compliance with general R2E limits.

The secondary beam production target at future positron sources at the Continuous Electron Beam Accelerator Facility (CEBAF), the International Linear Collider (ILC) or the Future Circular Collider (FCC), features unprecedented mechanical and thermal stresses which may compromise sustainable and reliable operation. Candidate materials are required to possess high melting temperature together with excellent thermal conductivity, elasticity and radiation hardness properties. In order to substantiate the material choice for the CEBAF and ILC positron sources, the response of candidate materials such as titanium alloys, tungsten, and tantalum to electron beam irradiation was experimentally investigated. CEBAF and ILC expected operating conditions were mimicked using the 3.5 MeV electron beam of the MAMI facility injector. The material degradations were precisely analyzed via high energy X-ray diffraction at the HEMS beamline operated by the Helmholtz-Zentrum Hereon at the PETRA III synchrotron facility. This work reports the results of these measurements and their interpretation.

Ultrafast high-brightness X-ray pulses have proven invaluable for a broad range of research. Such pulses are typically generated via synchrotron emission from relativistic electron bunches. Recently, compact X-ray sources based on laser-wakefield accelerated (LWFA) electron beams have been demonstrated, where the radiation is generated by transverse betatron oscillations of electrons within the plasma accelerator structure. Here, we present a novel method for enhancement of and control over the parameters of LWFA-driven betatron X-ray emission. We realize this through specific manipulation of the electron bunch phase-space using our novel Transverse Oscillating Bubble Enhanced Betatron Radiation (TOBER) scheme. The phase space is controlled through the orchestrated evolution of the temporal laser pulse shape and the accelerating plasma structure, which leads to off-axis electron injection and large-amplitude transverse betatron oscillation, resulting in enhanced X-ray emission. TOBER holds the promise of compact sources that can generate X-rays with optimized parameters for specific applications using the same setup beams with even higher peak and average brilliance.

An effective high-power positron converter for electron linear accelerators is not currently available from industry. A commercial source would allow research institutes to have ready access to high-brightness positrons for a wealth of material science, nuclear, particle, and accelerator physics projects. Xelera Research LLC has designed, built, and tested a prototype free-surface liquid-metal (GaInSn) jet converter. Free-surface liquid-metal jets allow for significantly greater electron beam power densities than are possible with solid targets. Higher power densities lead to greater positron production and, importantly, allow continuous wave (CW) operation. A modified version of the GaInSn converter prototype is planned to be constructed and tested at the Thomas Jefferson National Accelerator Facility.

The Shanghai Light Source has been operated since 2009 to provide synchrotron radiation to 40 beamlines of the electron storage ring at a fixed electron energy of 3.5 GeV. The Shanghai Laser Electron Gamma Source (SLEGS) is approved to produce energy-tunable gamma rays in the inverse Compton slant-scattering of 100 W CO2 laser on the 3.5 GeV electrons as well as in the back-scattering. SLEGS can produce gamma rays in the energy range of 0.66 – 21.7 MeV with flux of 1e+5 – 1e+7 photons/s*. A positron source based on SLEGS is designed to produce positron beams in the energy range of 3 – 16 MeV with a flux of 1e+5 /s and energy resolution of ~7% with an aperture of 10 mm collimator. The positron generated has been simulated by GEANT4, uses a SLEGS gamma injected into a single-layer target, and a dipole magnet deflect positrons. Based on the energy-tunable SLEGS gamma rays, the optimized parameters at each gamma energy were simulated to obtain an energy-tunable positron source. We have confirmed positron generation in the commissioning. We plan to construct the positron source in the summer of 2024. We present the positron source based on results of simulation and test measurements.