For the Future Circular Collider (FCC) Conceptual Design Report (CDR), the FCC-hh collimation system was studied and optimized for proton and heavy-ion operation with up to 8.3 GJ stored beam energy. There are currently studies ongoing for an updated design baseline, including a new ring layout, compatible with the FCC-ee, and optics, where the collimation insertions have undergone major changes. A first iteration on the adapted collimation system layout and settings for the new baseline is presented. The beam loss cleaning performance for proton beams is studied in multi-turn tracking simulations.

In the FCC-ee study, it is proposed that electron and positron beams circulate at high current and high energy in a 92-km circumference ring. The present operational scenario foresees a first running step at an energy of 45.6 GeV and around 1.4 A current, which would generate copious amounts of synchrotron radiation (SR) power and flux. To guarantee a quick decrease of the photon desorption yields and so a fast vacuum conditioning, it has been proposed to use localized SR absorbers along the vacuum chamber, spaced about 6 m apart. This would also help contain the high-energy Compton-scattered secondaries once the beam energy is increased up to 182.5 GeV, later in the experimental program. In the preliminary design of FCC-ee vacuum chamber absorbers presented in this work, the SR thermal power is intercepted along around 100 mm of slanted surface. The temperature distribution in the adsorbers is estimated by Finite Element Analysis (FEA) and needs to be assessed to avoid any liquid-gas phase change within the water-cooling circuit. The cooling channels contain a twisted tape that increases the turbulence of water. This results in the desired heat transfer coefficient. The mechanical deformations due to the non-uniform temperature map are presented and analyzed as well.

Elettra 2.0 is the name of the upgrade project of the existing Elettra Storage Ring (SR) and its ancillary systems. The project comprises also new beamlines (BLs) and the re-allocation of some of the currently operational ones. Consequently, the “Experimental Hall” (EH) of Elettra, i.e. where the beamlines are installed, is another working area with activities that have started well before the scheduled “Dark Period” (DP) when we will dismantle Elettra and install Elettra 2.0. The installation of the beamlines implies, among many more activities, the partial reconfiguration of the shielding wall of the SR tunnel. Some of these local re-arrangements can be performed before the DP, during maintenance shutdowns of Elettra, in those portion of the EH not currently occupied by working beamlines. The reconfiguration of the shielding wall requires a design that merges SR and BLs specifications, as well as careful planning of on-site activities, spanning from survey and tracing of the new positions of the blocks, to plants re-arrangement, to handling and transportation of concrete blocks up to 6 tons. This paper illustrates the status of the reconfiguration activities of the Experimental Hall.

The Future Circular Collider (FCC) study comprises two accelerators, namely a high-energy lepton collider (FCC-ee) and an energy-frontier hadron collider (FCC-hh). Both rings share the same tunnel infrastructure, analogous to LEP and LHC. We present the current design status of FCC-hh, updated from the Conceptual Design Report (CDR) and with recent developments including the new designs of the combined injection and dump insertion, combined injection and RF insertion, new collimation insertions, as well as the optimization of the arc cells and dispersion suppressors to increase the dipole filling factor.

Over the last three years (2020-2022) Diamond Light Source has installed four in-house designed, built, and measured Cryogenic Permanent Magnet Undulators (CPMUs). All four are 2 m long with a 17.6 mm period and have a minimum operating gap of 4 mm. These have replaced existing 2 m long in-vacuum pure permanent magnet (PPM) devices to improve the flux to several of Diamond’s MX (Macromolecular Crystallography) beamlines by a factor of 2-4. In this paper we present the mechanical and cryogenic design considerations, and the shimming procedures and tools developed to produce these devices. The performance of the CPMUs compared to their PPM counterparts will also be reviewed.

The potential future Soft X-ray (SXL) FEL beamline at the linear accelerator at MAX IV will require a series of undulators with distinct properties: It must be cost-effective and compact. Furthermore, it needs to have a small and round magnetic gap and provide elliptically polarized light under full polarization control. This undulator of a compact APPLE X type is currently being prototyped in the Insertion Device group at the MAX IV Laboratory. In this paper, we present the technical requirements of both, the mechanical and magnetic challenges that follow with the compactness and complexity of the device. Thereafter, we outline the assembly procedure of the undulator and present the methods we intent to use for magnetic measurements to evaluate the prototype's performance.

Hefei Advance Light Facility (HALF) is a 2.2 GeV diffraction-limited storage ring, which is developed by National Synchrotron Radiation Laboratory in China. It has 20 long straight sections and 20 middle straight sections. All the experimental stations in the first stage will employ undulator as the light source. In this paper, we introduce the preliminary design of insertion devices of HALF, which includes 11 undulators and 2 wigglers. The undulator design is carefully optimized based on the current undulator technology and experiment user demands. The photon flux of these undulators can cover the photon energy from 5 eV to 10 keV with the flux greater than $10^{14}$ phs/s/0.1\% B.W. It can reach an ultra-high brilliance at the soft X-ray wavelength region. Most of the insertion devices are the elliptically polarized undulators and the in-vacuum undulators, therefore the light source of HALF will be charactered by a flexible tunability on polarization state and a broad range of photon energy from VUV to X-ray wavelength region.

During the last run, the CLARA accelerator* ran with a 2.5 cell 10 Hz S-band RF gun which had a modified back plate to allow the use of INFN-style photocathode pucks. Previously this gun had used a solid wall back plate that also acted as the photocathode**. This presentation describes the different photocathodes that were used during the run and the various methods employed to prepare them for use. An initial cathode which was based on a solid Mo puck with the thin film of Cu grown using magnetron sputtering was seen to give high initial QE but a very fast degradation rate. Subsequent cathodes were hybrids with a Mo body and a solid copper tip for the active area. Several cathodes prepared using alternative techniques were employed, giving varied initial QE and lifetime. The final cathode used had satisfactory QE and a long enough lifetime to deliver a six month period of beam exploitation for external facility users. * D. Angal-Kalinin, et al, ‘Design, specifications, and first beam measurements of the compact linear accelerator for research and applications front end’ Physical Review Accelerators and Beams 23 (2020) 044801 ** T.C.Q. Noakes, et al, ‘Photocathode preparation and characteristics of the electron source for the VELA/CLARA facility’ Proceedings of the International Particle Accelerator Conference 2018 (IPAC-18), THPMK063, 2018, Vancouver, Canada

The Radio Frequency Quadrupole (RFQ) for the High-Intensity Photon Injector (IPHI) project has been designed and manufactured in the early 2000s. It is now operating at CEA Saclay since 2016 and accelerates a 100-mA continuous beam up to 3 MeV. It is a 6-meter-long, 3 segments vane RFQ, with 352.2 MHz operation frequency and non-constant voltage profile. From this RFQ, a lot of experience has been gained and, based on this feedback, other RFQ were designed at CEA, such as the one for SPIRAL2, LINAC4, or ESS, which are now operating. For maintenance purposes and to simulate the changes before we operate them, a new virtual 3D model has been developed. This model is simplified and may have the same RF performances as the existing one. This paper present this new model.

The MYRRHA project (Multi-purpose hYbrid Re-search Reactor for High-tech Applications) is a planned accelerator-driven system (ADS) that will be realised at Mol in Belgium and will demonstrate the feasibility of transmutation of radioactive waste on an industrial scale. The planned accelerator, which is to provide the 600 MeV proton beam, consists of a normal-conducting 17 MeV injector that supplies a superconducting LINAC. In addition to a 4-rod RFQ and two QWR rebunch-ers, 17 CH structures are planned in the injector, 15 of which will be used for acceleration and 2 as rebunchers. Now that the construction of the first two CH structures has been completed and they have been tested with per-formance, the next cavities are being prepared for con-struction. Since the next cavities are operated with more power than CH1 and CH2 due to the higher gap voltages re-quired, the cooling of the stems plays a decisive role for reliable operation due to the required cw operation. For this purpose, an insert was developed in several iterative steps that significantly lowers the maximum temperature on the stems.

The quarter wave resonator (QWR, a.k.a. λ/4 resonator) for the new ISIS MEBT is a bunching cavity that longitudinally compresses the H- beam into smaller bunches. It has 2 gaps with a distance of βλ/2 between mid-gaps, and works in π mode at the resonant frequency of 202.5 MHz, with a phase angle of -90 degrees. The maximum voltage per gap (E0L) is set to 55 kV. A detailed RF model has been developed to tune the main dimensions to the required frequency and to estimate the Kilpatrick ratio and the RF power dissipation. The cavity is designed to be made of copper plated stainless steel, which has a considerable effect on the design of the cooling system; the thermal calculations include a thermo-mechanical analysis to estimate the dynamic tuning requirements. The cavity has two tuners to allow for a fine and a coarse tuning of the resonant frequency. The manual tuner coarsely adjusts the frequency to cope with the manufacturing tolerances. The automatic tuner finely tunes the frequency within a range of working temperatures. The tuners are heavily coupled both in terms of frequency resolution and tuning range, which presents some challenges to the design. The design of the power coupler was adapted to the QWR from another project and the coupling coefficient was adjusted to the new cavity. A sensitivity analysis for the critical dimensions was also developed, but is not presented here.

Over recent years four dedicated facilities have been built at Daresbury Laboratory by a team working on thin film SRF cavities. Firstly, a conventional DC resistance facility allows measurements of critical temperature and residual resistance ratio. In addition, three other facilities were designed in house to address superconducting thin film (STF) characterisation specific to cavities. In a magnetic field penetration facility, a DC parallel magnetic field is applied locally from one side of the sample similar to the field within an RF cavity. The STF behaviour under RF conditions is tested with planar samples using a 7.8 GHz choke cavity with the main advantage of a quick turnaround. The final facility uses a novel idea of split single cell 6 GHz cavities. Such a cavity can be deposited with both planar and cylindrical magnetrons allowing for both deposition techniques to be tested in the same cavity. Also, the results can be compared to choke cavity measurements for planar samples. They can also be inspected easily both visually and with surface analysis instrumentation. All facilities are based on liquid helium free cryocoolers to simplify operation, safety and maintenance.

Nonlinear integrable optics (NIO) are a promising novel approach at improving the stability of high intensity beams. Implementations of NIO based on specialized magnetic elements are being tested at the Integrable Optics Test Accelerator (IOTA) at Fermilab. One method of verifying proper implementation of these solutions is by measuring the analytic invariants predicted by theory. The initial measurements of nonlinear invariants were performed during IOTA run in 2019/20, however the covid-19 pandemic prevented the full-scale experimental program from being completed. Several important improvements were implemented in IOTA for the 2022/23 run, including the operation at higher beam energy of 150 MeV, improved optics control, and chromaticity correction. This report presents on the improved calibrations of the NIO for nonlinear invariant measurements.

The effect of both existing and the planned insertion devices on linear optics, dynamic and momentum aperture was modeled using the kick map approach. Cross check for some IDs have been done with different tracking codes. Mitigation strategy for avoiding the crossing of a 4th order resonance line, excited by some of the IDs, is proposed.

KIT operates the storage ring KARA (Karlsruhe Research Accelerator) as an accelerator test facility, which serves as a testbed for different electron beam-based experiments. Thus, it motivates to study the beam conditions extensively. To extend the existing characterisation of non-linear parameters, the amplitude dependent tune shift (ADTS) was measured. ADTS is typically controlled by octupole magnets in a storage ring, which are not available at KARA, but the installed insertion devices exert a certain octupole component on the beam resulting in a change of the ADTS. This contribution presents measurements of the amplitude dependent tune shift for different combinations of active insertion devices.

Vacuum chambers of flat aspect ratio are source of a quadrupolar component of long-range resistive wall wake fields whose amplitude only depends on the trailing test particle. In multi-bunch filling this leads to an accumulation of the long-range quadrupolar resistive wall wake field which expresses in multi-bunch tune shifts on both planes. The tune shifts were measured at the ALBA storage ring and the results were compared to the model of Chao, Heifets and Zotter * and the model of Blednykh et al.**. As ALBA runs with only 8 insertion devices of which 3 are in-vacuum undulators in relatively short sections with low beta-functions, the quadrupolar detuning is dominated by dipolar vacuum chambers and the standard vacuum chamber around the ring. The effect of the in-vacuum undulators will be also discussed.

This paper presents the magnetic design, mechanical design and assembly tooling design for four 500T/m Hybrid Halbach Quadrupoles with an aperture radius of 4mm. The quadrupoles will be used for capture of a 1-5 GeV electron beam produced in a plasma acceleration stage at the Extreme Photonics Application Centre which is currently under construction at Rutherford Appleton Laboratory in the United Kingdom. In order to meet the stringent requirement dictated by beam dynamics studies, that the peak gradient of the four quadrupoles should vary by less than 1% in the presence of economically achievable engineering tolerances and magnetic field uniformity of the permanent magnet blocks, the design features a novel ‘3-bit tuning system’ in which three steel rods can be inserted in 8 different combinations into each steel magnet pole to tune the gradient in evenly spaced steps of 0.8% over a full range of 6%. This 3-bit tuning system can be used to ensure the specification on uniformity over the four quads is achieved.

The Radia code is used widely to model magnets for various particle accelerator applications, especially for insertion devices at synchrotron radiation sources. Although Radia provides many useful capabilities, including generally nonlinear relationships between applied fields and material magnetization, it previously lacked a full description of the hysteresis dynamics present in ferromagnetic materials. We have developed extensions to theRadia Python interface which currently include two models, Jiles-Atherton and Preisach, that enable users to account for fully hysteretic dynamics in their magnet simulations. Our contributions feature efficient numerical implementations as well as useful loop-tracing and interpolation methods to allow users to accurately model developing dynamics during a simulation.

Developing HTS dipole inserts producing fields larger than 5 T within 15 T Nb3Sn outserts is necessary to generate 20 T or higher fields for future high energy colliders. Dipole inserts based on the cos-theta coil geometry with various stress management concepts and Bi2212 super-conducting strand and cable are being developed at Fermilab both within and beyond the U.S. national effort. On paper, the potential reach for the maximum magnetic field in existing or planned Nb3Sn outserts is close to 20 T, thanks to the progress realized in Bi2212 wires’ critical current density. To achieve the Bi2212 potential in accelerator magnets, however, a number of technological challenges still have to be faced. These for instance include the need to design billets that are adequate for Rutherford cabling; developing insulation processes and materials that prevent leaks, which reduce transport current and increase the risk of shorts; control and limit Bi2212 coils’ stresses and strains; reconsider the Split Melt Process (SMP) to lower costs and simplify the processing. This paper reviews Bi2212 conductor properties and coil technolo-gies, and proposes new ideas to face the challenges that Bi2212 still presents as an accelerator magnet conductor.

The insertion device for FAXTOR, the new hard XR tomography beamline at ALBA, is a 54mm-period in-vacuum wiggler. The device is of hybrid PM-type, consists of 11 poles for a total magnetic length of 362mm, and it will operate at a minimum mechanical gap of 5mm. The device has been manufactured by AVS Company. During the manufacturing process, the field quality of each individual magnetic arrays was checked and adjusted, but it was not possible to verify the magnetic performance of the whole device once the arrays were integrated on the final support structure. This last step has been carried out at ALBA magnetic measurements laboratory upon the delivery of the device, using our Hall probe bench for closed structures and a flipping coil bench. In this paper we present the results of the magnetic characterization and the final adjustments that have been implemented, as well as the integration of the device into ALBA Storage Ring.

The Insertion device development and measurement laboratory of Devi Ahilya University, Indore, India has ongoing activities on undulator design, development and measurements. A new type of undulator known as Asymmetric magnet pole with upper and lower structure having different period lengths will be designed and fabricated. Asymmetric magnet pole undulator has a special demanding field quality for suppressing the higher harmonic components of radiation and reducing on axis heat load from radiation. The undulator will be a variable gap undulator with upper structure consist of 25mm period having NdFeB magnets of rectangular cross section 6.25 mm, 6.25 mm and 50mm and lower structure will be with 50mm period length with the same magnet material but having rectangular cross section of 12.5mm, 12.5mm and 50mm. In this paper the design details for an asymmetric magnet pole undulator will be presented.

After 20 years of use, the Hall-probe system at the Na-tional Synchrotron Radiation Research Center (NSRRC) has poor measurement reproducibility. The granite bench is 6m long and is robust but the Hall-probe stage with air bearings has deteriorated. To create a reasonable operat-ing space for field correction for an insertion device (ID), the distance between the ID and the measurement system must be increased so a more stable and accurate stage is required. The developed system has a new structure to isolate the imbalance in the forces that act on it when the Hall probe stage is moving and the cable drags. An opti-cal position sensitive detector (PSD) is also fitted to measure the change in the position of the hall probe in space. The positional error in space for the Hall probe is now less than 15um. This is achieved by measuring and correcting the position in real time.

The Upgrade from the third to the fourth-generation light source of the SOLEIL synchrotron requires significant work on the reorganization of the equipment in the storage ring. Higher performance such as low emittance, small transverse size and high brightness are expected but requires redesigning the lattice. New constraints appear, requiring innovative designs of insertion device (ID) in order to keep the spectral range currently offered to users as large as today. The current straight sections can welcome two juxtaposed undulators to allow the beamline to cover a wide spectral range. However, the average space of straight sections dedicated to ID of SOLEIL II will be decreased in the future by 30%. SOLEIL Insertion Group studied several technical solutions combining two magnetic periods in a shorter space. Bi-periodic undulator project would make it possible to design a unique compact device with special magnet arrangement allowing to operate the ID alternatively with one periodicity to its triple value by means of longitudinal displacement of magnet arrays. Such an undulator enables to cover a wide spectral range of photons and only requires short space. A complete magnetic design with magnetic and spectral/optical performance will be presented and compared to usual solutions. Impact on the electron beam dynamics and magnetic forces will be also considered to have a complete knowledge on the feasibility of this project.

In preparation for the High Luminosity phase of the LHC at CERN, to start in 2029, a refurbishment of the electronics of the CMS electromagnetic calorimeter (ECAL) is planned. The ECAL barrel section is organized in 36 elements called Supermodules (SMs), 18 in each side. All SMs, weighing about 3 tons each, must be ex-tracted, upgraded and inserted again during the Long Shutdown 3 (LS3) using two large machines, Enfourneur n.1 (E1) and n.2 (E2) operating one per each CMS side. E1 – used for the original SMs installation - has been heavily upgraded to be compliant with the current safety norms, but the demands from the logistics of the CMS cavern and the tight schedule require to produce a second machine. The new E2 machine must meet some major engineering challenges: maintaining or improving func-tionality and safety in compliance with European regula-tions in terms of safety (Eurocodes and the Machinery Directive in particular), as well as being installable in the CMS plus side, which is only accessible through narrow shafts and tunnels. E2 was therefore designed in a modu-lar way, harmonizing functional and structural require-ments with the space and tools available for transport and installation. Functionality and safety have also been improved by replacing hydraulic actuation with electri-cally driven controls and motors, resulting in refined positioning capabilities and simplified procedures for handling heavy, voluminous, and extremely delicate objects such as supermodules. The E2 design is currently complete and the construction has started in January 2023.

The Electron Ion Collider (EIC) Hadron Storage Ring (HSR) will reuse most of the existing superconducting magnets from the RHIC storage rings. To comply with the more demanding operational scenarios imposed by the EIC hadron beams, the beam pipes of the reused RHIC magnets will be equipped with low surface impedance and low SEY screens. The installation of these screens will be done with the superconducting magnets as installed, making it a critical operation for a timely EIC installation. On one hand the beam screen installation radial clearance must be as small as possible to maximize the superconducting magnet aperture. But on the other hand, keeping enough clearance is critical to ensure a smooth beam screen installation. In preparation for this work, an autonomous survey probe was designed and built to measure in-situ the magnet beam pipe inner diameter and provide critical data for the beam screen design and magnet aperture optimization. This paper reports on the design of the high-precision probe and the findings from its survey campaign.

Since its commissioning, operators at the Argonne Tandem Linear Accelerator System (ATLAS) have used an analog current meter to manually record beam current measurements from Faraday cups along the beamline. Recently an automated process using a digital picoammeter was developed for beam current measurements. This automation has streamlined daily operations, increased the precision of measurements, and expedited the generation of digital data for use with ongoing artificial intelligence and machine learning work (AI/ML).