MYRRHA will be a research infrastructure focussed on the construction of a first prototype of an accelerator driven sub-critical nuclear reactor (ADS). The driver ac-celerator will deliver a 600 MeV, 4 mA Proton beam to the reactor core. The first phase called MINERVA aims for the construction of a 100 MeV, 4 mA proton linear accel-erator with a focus on reliability. Attached to this 100 MeV linear accelerator are a Proton Target Facility (PTF), which is essentially a high power Isotope Separation On-Line (ISOL) Facility, and a Full Power Facility (FPF) for fusion material research. This paper presents the status of the beam optic studies and overall layout of the Protons Target line towards the PTF, the Full Power line towards the FPF and the beam line towards an energy tuning beam dump.

The Insertion Region 2 (IR2) will accommodate a Pre-Cooler at injection energy ($24~\mathrm{GeV}$) and a Strong Hadron Cooling (SHC) facility at top energy ($100~\mathrm{GeV}$ and $275~\mathrm{GeV}$) in the Hadron Storage Ring (HSR) of the Electron-Ion Collider (EIC). This paper summarizes the lattice update in HSR-IR2 to meet the requirements from the Pre-cooling and the SHC. The layout has been changed to provide a longer cooling section. It also describes how to enable vertical cooling for the SHC in IR2.

CNAO is one the six hadrontherapy centers all around the world that produce both proton and carbon ions beams. It is based on a synchrotron in which the beams are extracted by a slow extraction mechanism that uses a betatron core. In the last years an electrostatic exciter has been installed along the ring in order to allow beam extraction using the RF-KO method. The system has been commissioned and allows extraction according to the clinical beam parameters. The paper illustrates how the RF-KO method has been implemented in CNAO under the hardware and software point of view. The characteristics of the proton and carbon beams will be also presented.

The BEPCII has already realized the collision luminosity target of $1.0\times10^{33}cm^{-2}s^{-1}$ in April 2016. However, in the past six years of practical operation, the collision luminosity usually remains between $6.0\times10^{32}cm^{-2}s^{-1}$ and $8.5\times10^{32}cm^{-2}s^{-1}$. In the operation with high beam current, the BEPCⅡ displayed serious beam instabilities, which greatly limits the increase of collision luminosity. A series of machine studies and analyses were conducted. According to the bunch lengthening experiments, the longitudinal effective impedance is $0.162\Omega$ for electron storage ring and $0.195\Omega$ for positron storage ring. According to the tune shift measurements, the transverse effective impedances are $0.02840\Omega/m$ horizontally and $0.05253\Omega/m$ vertically for electron storage ring, and $0.04223\Omega/m$ horizontally and $0.06714\Omega/m$ vertically for positron storage ring. The oscillation mode distribution was obtained from experiments, showing that the transverse beam coupling instability has become an important factor for limiting the increase of beam current and luminosity. Finally, some possible origins of transverse narrow-band impedance, such as the resistive wall and vertical masks, were checked. The calculated results match with the experiment results quite well. The results in this study give important references for establishing feedback systems and increasing the collision luminosity in the future research.

The High Energy Photon Source is a 6 GeV synchrotron radiation light source being built in Beijing, China. The electron beam inside the storage ring is designed to run with ultra-low emittance. To ensure high beam quality, the coupled bunch instabilities must be carefully investigated and controlled, therefore an effective feedback system is essential. Stripline kickers are designed for transverse feedback in the HEPS storage ring. The basic structure and main simulation results of these kickers are introduced, including the reflection parameter, transverse shunt impedance, and wake effects.

The Super Proton Synchrotron (SPS) injection system plays a fundamental role to preserve the quality of injected high-brightness beams for the Large Hadron Collider (LHC) physics program and to maintain the maximum storable intensity. The present system is the result of years of upgrades and patches of a system not conceived for such intensities and beam qualities. In this study, we propose the design of a completely new injection system for the SPS using multi-level numerical optimisation, including realistic hardware assumptions. We also present how this hierarchical optimisation framework can be adapted to other situations for optimal accelerator system design.

The LHC beam dump system has the task of safely and reliably disposing of the extracted beams from 450 GeV to 7 TeV. The present dump assembly consists of a multi-segment graphite core, which is contained in a duplex stainless steel vessel with titanium windows. To reduce the energy deposition density in the core and windows, the extracted beams are swept across the dump front face with dedicated dilution kickers. In the High Luminosity-LHC (HL-LHC) era, the dump must withstand beams with a significantly higher stored energy (about 700 MJ) than has been achieved so far (380 MJ). The high temperatures and vibrations generated in the core and vessel require a redesign of the dump assembly to ensure safe operation with HL-LHC beams. This work presents energy deposition studies for the different dump components in case of regular dumps and possible dilution kicker failure scenarios during HL-LHC operation. The impact of different design choices, such as the dump core segmentation, on the energy deposition and the leakage of particles from the dump is discussed.

To explore the beyond standard model of elementary physics, we proceed a new fundamental physics experiment, J-PARC muon g-2/EDM experiment. To realize very precise measurement of the muon spin precession frequency in the level of sub-ppm, a relativistic energy of muon beam is injected into a precisely adjusted storage magnet of sub-ppm uniformity by applying medical MRI magnet technologies. Three-dimensional spiral beam injection scheme is intended to storage in 0.66 m diameter compact ring, we have carefully studied of a spatial distribution of a radial magnetic field of the storage magnet and required beam phase space, especially for a strong X-Y coupling. In this presentation, we will discuss about a strategy to precise control of the X-Y coupling at the beam transport line: how to detect X-Y coupling from a beam phase space, how to control X-Y coupling with eight independent rotatable quadrupole magnets. We also discuss about how to apply fine-tuning of the beam trajectory without disturbing the magnetic field in the beam storage volume, by use of active shield multipole coils. Finally, we will report detailed studies of X-Y control at a demonstration beam line in KEK which proves the three-dimensional injection scheme is realistic one, as well as further challenges towards the original beam line at J-PARC.

The Proton Storage Ring (PSR) of LANSCE compresses the pulse of a linac-produced beam by a factor of more than 2000 into an ultra-short high intensity beam, making the Lujan Center a leading facilities in the delivery of instantaneous beam power. This short-pulse feature allows a variety of experiments from neutron science to fundamental nuclear physics. Further shortening the beam pulse by another factor of 2 is necessary to achieve high-resolution nuclear data the search for Beyond Standard Model particles. We will report on our current status in our research to simultaneously stack two shorter pulses into the PSR by repurposing existing components in a system that, unlike synchrotrons, has limited flexibility.

Hefei Advanced Light Facility (HALF) was designed as fourth generation light source based on the diffraction-limited storage ring (DLSR). The pre-research has been completely done, due to the smaller beam dynamic aperture, about 10mm, beam inject could not completed by the traditional bump magnet. We purposed and designed a novel dual-channel kicker, with other two traditional kicker, they were combined the new injection system. The paper presented the principle and layout and the detail of the novel dual-channel.

In the Advanced Photon Source Upgrade storage ring, the horizontal collimators protect the rest of the machine from whole beam aborts; however, as shown in previous experiments, the collimators themselves must also be protected from the full intensity of the lost store. The suitability of a vertically-deflecting fan-out kicker was evaluated experimentally. Aborted beam strikes the surface of the collimator with the expectation that the absorbed energy density or dose is reduced sufficiently to maintain the integrity of the device. We discuss the results from recent measurements where a fan-out kicker was employed to test this concept. 6 GeV, 200 mA (737-nC) APS stored beam was used to irradiate both aluminum and copper collimator test pieces.

The European Synchrotron Radiation Facility - Ex-tremely Brilliant Source (ESRF-EBS) is a facility upgrade allowing its scientific users to take advantage of the first high-energy 4th generation storage ring light source. In December 2018, after 30 years of operation, the beam stopped for a 12-month shutdown to dismantle the old storage ring and to install the new X-ray source. On 25th August 2020, the user programme restarted with beam parameters very close to nominal values. Since then beam is back for the users at full operation performance and with an excellent reliability. This paper reports on the present operation performance of the source, highlighting the ongoing and planned developments.

The Electron Ion Collider (EIC) Hadron Storage Ring (HSR) will utilize the Relativistic Heavy Ion Collider (RHIC) arcs and modified straight sections. Due to these modifications in the straight section of the on project electron Proton Ion Collider (ePIC) experiment, a new injection system needed to be built one arc downstream of the existing RHIC injection system. The new injection system will have capability of injecting 290 bunches with a maximum rigidity of ~81 Tm. In addition to the new injection system, the hydrogen jet (HJET) and proton-carbon (pC) polarimeters will be located in the straight section downstream of injection. This paper will report the modifications required to the lattice, optics, and magnets.

A Multipole Injection Kicker (MIK) has been successfully designed, constructed, installed and commissioned with beam in the MAX IV 1.5 GeV ring. This device allowed reaching injection efficiencies as high as those obtained with the previously used conventional dipole injection kicker scheme, while at the same time providing an order of magnitude reduction in the perturbations to the stored beam resulting from the injection process. In addition, the device has had a major positive impact in allowing effective top-up injection under the strong optics perturbations generated by long-period elliptically polarizing undulators. In this paper we describe the first operations with the device and detail the process of optimisation and commissioning.

With the growing interests and new experimental development in time-resolved studies at Stanford Synchrotron Radiation Light Source (SSRL), we are motivated to develop the Pseudo Single Bunch (PSB) operational mode to address the requirements from time-resolved and regular user experiments simultaneously. In this paper, we will present the physics design for this new mode. Beam line simulations for performance evaluation of the user experiments are also reported.

The Korea fourth generation storage ring (Korea-4GSR) is a 4GeV, low emittance light source to be built in Ochang, Korea. The booster ring, which consists of 26 FODO standard cells and 2 dispersion-free cells, ramps the beam energy up from 200 MeV to 4 GeV as part of the injector. The circumference and repetition rate of the booster ring is 772.9 m and 2 Hz, respectively. In this paper, the injection scheme, energy ramping curve, eddy current effect, beam parameters changing curve, and RF voltage during the energy ramping in the booster ring will be presented in detail.

The feasibility of performing sextupole injection at TPS (Taiwan Photon Source) storage ring has been demonstrated in November 2021 with 300 mA stored electron beam. In order to carry out the experiment, a sextupole and its associated pulser were fabricated according to the specifications required. The sextupole was installed during a short break in September 2021 by making use of a ceramic unit located between kicker-3 and kicker-4 at the injection straight section. Moderate adjustment of the beam injection trajectory at the BTS (booster-to-storage ring) transfer line is needed so as to avoid beam scraping off at the injection septum. A brief description of the preparation work is given and the experimental results are summarized in this report.

The Diamond-II storage ring has been designed to increase photon brightness by up to two orders of magnitude compared to the existing Diamond facility. A single-bunch aperture sharing injection scheme using short stripline kickers applied with high-voltage nano-second pulsers was proposed to provide both high injection efficiency and high photon beam stability in top-up mode [1]. The quasi-transparent injection process has been optimised and studied using Accelerator Toolbox. The results of these study will be presented.

Top-up operation at BESSY II is performed with average injection efficiencies of 98 %. However, the four-kicker bump and the septum, that form the present injection system, both contribute to a distortion of the stored beam with an amplitude of about two millimeters for several thousand turns after injection. A non-linear injection kicker (NLK) could be used to reduce the distortion due to the kicker bump by a factor of approximately 30 - a necessary condition for transparent injection. Studies with an NLK and optimized sextupole settings have shown that it is also possible to achieve injection efficiencies of up to 97 %. The NLK was characterized beam-based with regards to the application of the NLK for BESSY II user operation, a possible injection method for BESSY III and to get a better understanding of the limiting effects of the injection efficiency. Additionally, measurements and simulations were compared.

In the fourth-generation storage ring light sources, the dynamic acceptance is usually small related to the extremely strong nonlinearity inherent in the multi-bend achromat design, making it difficult to implement traditional off-axis local-bump injection. It was found that a double-frequency rf system can be used for longitudinal injection with the help of rf gymnastics. However, such schemes require tuning the RF parameters during injection, which would challenge the RF hardware system and cause the bunch length shrinking of the circulated bunch. In this paper, we find that with proper parameters optimization, a double-frequency RF system with static parameters can be used for longitudinal injection. A detailed design of this scheme for the application in the Southern Advanced Photon Source (SAPS) is presented.

Compared to the conventional injection scheme, the three-kicker bump injection scheme with an anti-septum has two advantages. One is less requirement of dynamic aperture thanks to the thin blade of the anti-septum, the other is less installation space requirement of the injec-tion system. Both are beneficial to the beam injection for the fourth generation light sources. In this study, the application of this injection scheme to the HALF storage ring is presented. The layout and parameters of the injec-tion system are designed and the injection process is simulated. The results of the injection efficiency and the effect on the stored beam during beam injection is shown in this paper.

The single nonlinear kicker (NLK) injection has been adopted by several synchrotron radiation light source facil- ities or their upgrades. The injected beam receives a kick from an NLK and goes into the acceptance of the storage ring while the stored beam passes through the center of the NLK where the magnetic field is almost zero. Compared with the local-bump injection, NLK injection requires less space for kickers and causes less oscillation amplitude for the stored beam during injection. Currently, a conventional local bump injection including four pulsed dipole kicker magnets is adopted in the HLS-II storage ring. In this paper, we propose an NLK injection scheme by only replacing one kicker with a pulsed NLK for HLS-II. The simulation result is also presented.

Wuhan Advanced Light Source (WALS) is the low-energy 4th generation advanced light source, which is proposed by Wuhan, China. WALS includes a 1.5 GeV full-energy LINAC injector, a 180 m circumference, 1.5 GeV low-emittance storage ring, and a series of start-of-the-art beam lines. The standard 7BA magnetic focusing structure is adopted for the storage ring to lower the beam natural emittance and the lattice has been well- designed and optimized by multiple-objective genetic algorithm to maximize the dynamic aperture and energy acceptance. The dynamic aperture of the storage ring at injection can reach up to 8 mm in the horizontal plane, which makes the off-axis beam injection method possible. An off-axis beam injection scheme based on the pulsed nonlinear magnet is to be employed for the storage ring. Detailed studies about the beam injection scheme, including the beam optical design, nonlinear magnet design and optimization, have been performed and multi-particle simulations have also been carried out to study the beam injection procedure, which will be presented in this paper.

The LHC Injector Upgrade (LIU) programme forms a cornerstone of the High-Luminosity LHC project. Among its targets, a new Beam Position Monitor (BPM) system has been deployed in the Low Energy Ion Ring (LEIR) to facilitate optics measurements. This paper reports on the commissioning and analysis of turn-by-turn data from the new BPM system. Furthermore, the specific challenges and current limitations in LEIR for achieving long-term coherent excitations with sufficient amplitude for optics measurements are discussed, as well as some of the optics measurements performed so far.

A 1–2 GHz stochastic cooling system is being de-veloped to provide fast 3D cooling of hot secondary beams (antiprotons at 3 GeV and rare isotope ions at 740 MeV/u) at intensities up to 10^8 particles per cycle. For antiproton cooling, cryogenic plunging pick-up electrodes will be used to improve the ratio of Schott-ky signals to thermal noise. To cool hot rare isotope beams quickly, a two-stage cooling (pre-cooling by the Palmer method and main cooling by the notch-filter method) has been decided. This paper presents the recent R&D highlights of this unique stochastic cool-ing system especially the main sub-systems i.e. two cryogenic plunging slotline pick-ups, one Palmer pick-up, and two slot-ring kickers.

The Cyrcé facility of IPHC in Strasbourg operates a TR24 cyclotron to produce medical isotopes, lead radiobiology programs and test detectors. A RF kicker has been developed in order to discard one beam bunch over two to get a rate close to 40MHz. An RF voltage at a quarter of the cyclotron frequency applied to a deflector in the injection line allows to reach that goal. The 30keV DC beam from the ion source is discarded except at the zero crossing of the RF. With a proper phase difference between the two RF, only one accelerating phase of the cyclotron over two is populated resulting in a bunch rate of 42.5MHz. A second need for radiobiology is to switch the beam on and off with the highest raise and fall times. This is done by adjusting the phase of the kicker to block the beam. The kicker is made of a collimator (diam. 8 mm), followed by 2 deflectors ( 55 mm long, 50 mm wide) spaced by 40 mm and a second collimators (diam. 6mm) at 160 mm downstream the deflectors, also used as a beam dump for the deflected ions. The high voltage is achieved by a resonant circuit consisting of a coil and the deflector, excited by a second coil. A second variable capacitor is added for tuning. The excitation coil position allows to adjust the matching. Scintillators associated with fast electronics has shown that the bunche rate was half the cyclotron frequency as expected. The beam rejection was measured to values up to 10-5. The raising and falling times of the beam was measured to 10µs.

The {2, 2} Danilov distribution is self-consistent — it is a Vlasov equilibrium distribution that produces linear space charge forces. Additionally, the distribution has zero (four-dimensional) transverse emittance. Thus the Danilov distribution may be of use for overcoming space charge limitations at high intensities, increasing collider luminosity, or pushing the limits of transverse bunch compression using round-to-flat transformers. When such a distribution is matched to one of the eigenmodes of a ring it is possible to use phase space painting to build the distribution over many turns, maintaining self-consistency throughout. This provides a way to create high-intensity beams with unique properties that could increase accelerator performance, with direct implication for experiments.  Here we report on the results of a proof-of-principle experiment using the flexible transverse phase space painting system at the Spallation Neutron Source to demonstrate the creation of an approximate Danilov distribution, including the effect of recently installed solenoid magnets.

Proton FLASH, which combines the advantages of a better spatial dose distribution of protons with the unique temporal effect of FLASH radiotherapy, is currently a hot topic of international research. Proton FLASH radiotherapy is technically demanding and currently lacks equipment support. There are only a few devices that have been modified to achieve small target section, fixed-energy penetrating irradiation by proton radiotherapy equipment, which cannot give full play to the advantages of proton spatial dose distribution. In this study, a series of innovative methods are proposed to manipulate the beam from the longitudinal dynamics level and to extract particles from the synchrotron, thus meeting the dose rate requirements for proton FLASH radiotherapy in a 1L volume in the target area. In combination with the splitting of small beam clusters, a synchrotron scheme for point scanning of proton FLASH radiotherapy is proposed for the first time. The synchrotron is used to control the number of particles required for a single scan point and to rapidly change energy, which solves the problems of long intervals between different energies and scan points of conventional point scanning and increases the dose rate in the target area. It provides a possible technical route to support the development of proton FLASH radiotherapy and enriches the application scenario of synchrotron.

Novel iron lamination with additional interlaminar insulation has been successfully developed for magnet cores of fast kicker magnets in particle accelerators. By minimizing the eddy current induced between core laminas, a pulse profile of the excited magnetic field has been significantly improved up to a few MHz range. The magnet core is formed by alternately stacking thin steel and insulation sheets to avoid electrical contact between the steel sheets on the cutting edge. A pair of test magnets with the new iron lamination was assembled to evaluate magnet performances focusing on applications to matched kickers in the accelerators. The magnetic field pulse profiles of the two magnets have successfully proved to match below 0.1% over the entire pulse duration, which is significantly better than those with conventional iron lamination. The developed fast kicker magnets are promising for the beam injection kickers in the coming next-generation light sources and future colliders, where suppression of the transient stored-beam oscillation during beam injection is crucial.

In the next-generation light sources, the bunch lengthening using the combination of the fundamental and harmonic cavities is a key technology to generate ultra-low emittance beam. Since the performance of the above bunch lengthening is limited by the transient beam loading (TBL) effect on the cavities, we proposed a TBL compensation technique using a wide-band longitudinal kicker cavity [1]. Then, we considered the kicker design based on the KEK-LS storage ring as an example of the next-generation light sources [2]. We employed a frequency of 1.5 GHz (third-harmonic) and the single mode (SM) cavity concept where harmful HOMs are damped by rf absorbers on the beam pipes. The SM-type concept has two advantages. One is its simple structure where it has no HOM dumper on the cavity and another is its low R/Q which reduces the TBL effect in the kicker itself significantly. The RF power is supplied with two large coupling holes whose total external Q is 300. The small external Q is essential to provide a voltage of 50 kV with a -3dB bandwidth (BW) of about 5 MHz which is needed to compensate for the TBL effects sufficiently. To verify the small external Q and damping of HOMs, we fabricated the low-power model of the kicker and measured its performance. In this presentation, we introduced the kicker's design and the performance tests' results.

SIRIUS is the 4th generation storage ring-based synchrotron light source built and operated by the Brazilian Synchrotron Light Laboratory (LNLS). Beam accumulation at SIRIUS storage ring occurs in an off-axis scheme, using a nonlinear kicker (NLK), for which the efficiency depends on a sufficiently large dynamic aperture (DA). This work reports on the application of online optimization using the Robust Conjugate direction Search (RCDS) algorithm on SIRIUS sextupoles, which resulted in improvements to injection efficiency and DA in three different machine working tunes.

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.

Impedance modeling is an important subject in diffraction limited storage rings based light sources, due to the adopted small beam pipe as well as the tight requirements from beam collective effects. Therefore, a batch of impedance bench measurements are performed or planned for the dominant impedance contributors in HEPS, including resistive wall impedance of the NEG coated vacuum chambers, as well as the geometrical impedance of components with large impedance for single element or that show large contributions due to large quantities. In this paper, the impedance measurement of the key elements in the HEPS will be discussed, and the main results are given and compared with the theoretical estimations.

In the framework of the High Luminosity Upgrade of the LHC (HL-LHC) the beam intensity from the injectors must be doubled while keeping longitudinal beam parameters unchanged. As such, high-quality beams with high intensities are required also from the Proton Synchrotron (PS). The beam coupling impedance plays a crucial role and mitigation measures must be taken to remain within a stringent impedance budget. Kicker magnets are important contributors to the overall broadband impedance of the PS. Moreover, the detailed study of kicker impedances revealed additional resonant modes which may be critical for the beam stability. The longitudinal beam coupling impedance for the fast extraction kicker KFA79 is presented in this study, and a solution to reduce the impedance of the critical resonant modes is introduced. Electromagnetic (EM) simulations have been performed to determine the impedance behaviour. Finally, the insertion of transition pieces between magnet modules is presented as a measure for mitigating the low frequency resonant impedance contributions.

After the LHC Injectors Upgrade (LIU) project, the CERN Proton Synchrotron Booster (PSB) operates with a new injection kinetic energy of 160 MeV and an extraction energy of 2 GeV. In light of this, several measurements have been performed to characterize the behaviour of the accelerator in terms of beam stability and beam coupling impedance in the new energy range. In particular, the horizontal instability observed in 2021 at about 1.7 GeV (between the old and the new extraction energy) has been deeply investigated and betatron coherent tune shift measurements have been carried out to further benchmark the PSB transverse beam coupling impedance model. Regarding the horizontal instability, although a mitigation strategy has been identified, measurements and studies have been conducted to understand and explain its source.

Beam-induced heating of equipment can have several undesirable effects, including rendering the equipment temporarily inoperative, equipment degradation and/or damage. Hence, to avoid these problems, it can be necessary to limit beam intensity. Beam-coupling impedance mitigation of existing devices and/or design optimization of new accelerator elements are essentials to overcome these limitations. In this framework a very good example is the optimization of the SPS kickers beam-coupling impedance for beam-induced heating mitigation. This paper describes the beam-coupling impedance measurements and simulation studies performed to identify and potentially remove the intensity limitation arising from the excessive beam-induced heating of a SPS injection kicker.

The Rapid Cycling Synchrotron (RCS) in China Spallation Neutron Source (CSNS) is a high intensity proton accelerator, the impedance can drive collective instabilities and limit the machine performance. Due to new component installation, the impedance model should be updated. A thorough estimation of the coupling impedance is presented and the impedance model in the RCS is obtained.

The standard injection scheme of ILSF is composed of 2 septum and 4 kicker magnets installed in a 7-meter-long straight section. Further tuning of the 4 kicker devices to reduce perturbations has proven to be almost impossible since it requires having 4 identical magnets, electronics, and Ti-coated ceramic chambers. Different from pulsed dipole kicker magnets used in a conventional local-bump injection, the single nonlinear or multipole kicker provides a nonlinear distribution of magnetic fields, which has a maximum value off the axis where the injected beam arrives and a zero or near-zero value at the center where the stored beam passes by. So, here the designs of different multipole kickers, including sextupole, octupole, and a nonlinear kicker, have been investigated and compared.

The Hefei Advanced Light Facility (HALF) is a vacuum ultraviolet (VUV) and X-ray diffraction-limited storage ring light source. It has a relatively large dynamic aperture, and an injection scheme with a nonlinear kicker (NLK) was considered for the HALF. This kind of magnet was designed with a small gap shield in the central area to gain a flat magnetic field. A complete prototype has also been produced and the measurement of magnetic field was done. In this paper, an improved structure of the nonlinear kicker is presented based on the previous one. Simulation of the longitudinal impedance has also been done and will be given later.

A new kicker power supply using SiC-MOSFETs is under development at J-PARC. SiC-MOSFETs enables the fabrication of compact high-speed pulse power supplies to replace thyratrons switch power supply. The base circuit uses an induction voltage superposition circuit of the LTD method, and the semiconductor module circuit consists of a radial symmetry type that achieves low noise. The three main parts of an existing kicker power supply, the thyratron, PFN circuit, and end clipper, can be configured in a single module circuit. The power supply consists of a 1.25kV/2kA main circuit module board that forms a trapezoidal pulse and a 0.1kV/2kA correction circuit module board that compensates for droop of the flat section. The thirty-two main circuit module boards and twenty correction circuit module boards are connected in series in a hierarchical manner to achieve the waveform specifications required for J-PARC RCS kicker power supplies: output voltage of 40kV, output current of 2kA, and pulse width of 1.2us. In addition, an insulating cylinder for conductors has been developed that suppresses corona discharge and withstands continuous operation for long periods of time.

One of the projects for upgrading at the Taiwan Photon Source (TPS) is the design and fabrication of an improved multipole injection kicker (MIK). The aim is to improve the injection efficiency using four kickers, to deliver transparent injections during the top-up operation. A uniform titanium coating on the inner surface of the ce-ramic substrate is required to reduce the impedance of the stored electron beam and to conduct the image current. The study results of the deposition of a titanium film on a ceramic substrate (30 cm × 6 cm ) in a long vacuum chamber show that the thickness uniformity of the thin film can be controlled within 5 % with an electrical resis-tivity of 2 × 10-4 ohm-cm. The adhesion between the ceramic substrate and the titanium film meet the highest ASTM-D3359 5B requirements (bonding strength 39.2 MPa). The details of the coating set-up, experimental processes and measurement method are described in this paper.

The CERN PS booster features four extraction kicker systems, one for each of the four superposed rings and three transfer kicker systems for recombination of the beams when being transferred towards the PS. Each of these systems consist of SF6 gas filled Pulse Forming Lines (PFL) which are resonantly charged and then fast discharged by thyratron switches into SF6 gas filled transmission cables, transferring the pulse to the magnets. This paper outlines the future refurbishment of PFL and transmission cables with the constraint of minimizing SF6 gas usage. The pulse requirements are presented since they limit the choice of technology together with the development cost for alternative SF6 free technologies. The optimization potential regarding technical pulse requirements versus beam performance is discussed. The paper concludes with the choice made and the technical design outline for the refurbishment of the PSB transfer and extraction kickers.

The CERN SPS injection kicker magnets (MKP) were developed in the 1970's, before beam power deposition was considered an issue. There are two types of these magnets in the SPS: MKP-S (small aperture) and MKP-L (large aperture) versions. The MKP-L magnets are very lossy from a beam impedance perspective: this would be an issue during SPS operation with the higher intensity beams needed in the future for HL-LHC. Hence, a beam screen has been developed, which is inserted in the aperture of each MKP-L module. The screen consists of silver fingers applied to alumina U-shaped chambers: the fingers have been optimized to achieve both adequately low beam induced power deposition and good high voltage (HV) behaviour. A surface coating, with a low secondary electron yield, is applied to the inner surface of the alumina chambers to reduce dynamic vacuum. The low-impedance MKP-L has been extensively HV tested in the lab before installation in the SPS. This paper briefly presents the design and focuses on the operational experience in the SPS, including heating and vacuum.

CERN is currently developing a 40 kV proof of concept Inductive Adder (IA) for replacing the Proton Synchrotron (PS) complex pulse generators, which currently use 80 kV SF6 gas filled pulse forming lines. The experience gained during the design, commissioning and operation of this prototype device will be crucial for upcoming decisions on the type of future kicker pulse generators. The cross-sectional area (CSA), hysteresis curve, biasing and material of a magnetic core determines its volt-time integral. In a terminated mode IA this parameter dictates the maximum pulse width that can be delivered into the load at a certain voltage. It is therefore key to measure the magnetic core response at the expected rate of magnetization (T·𝜇s−1) to assess its capability. Measurements and analysis yield important information for choosing the core CSA per IA layer and develop an accurate simulation model. In this paper BH curve measurements under different excitations of a toroidal, tape wound, nano-crystalline core are presented and discussed. Based on the results, pulse length/amplitude limitations are outlined and the required core CSA per inductive adder layer is proposed.

The "Facility for Antiproton and Ion Research" (FAIR) is a new international accelerator complex, which is currently built in Darmstadt, Germany. Part of this complex is the SIS100 heavy ion synchrotron with a circumference of ~1086 m. To inject ions into the SIS100, an injection kicker system will be required. For fast extraction of the particle beam from the SIS100, an extraction kicker is used. This extraction kicker will be capable of performing normal extraction or emergency extraction kicks depending on the requirements. To ensure the correct kick angle at any time, the emergency kicker is charged up to 80kV synchronously with the beam energy. Depending on the experiments and the kicker type, pulse durations can vary from 0.5 up to 7 us. Slow extraction of the ion beam will include an electrostatic septum, operating with voltages up to 180 kV. The actual design, progress in building and test results of these projects will be presented.

The High Energy Storage Ring (HESR) has been designed for acceleration and storage of antiprotons and ions by Forschungszentrum Jülich (FZ-Jülich) for FAIR in Darmstadt. The HESR kicker magnets have been designed for the injection of charged particles with magnetic rigidity of 13 Tm. Kicker magnets shall generate a total integral field of 57.8 mT during 500 ns with rise- and fall-times of less than 220 ns. To produce the neceassary injection field, a current pulse of up to 4000A/70 kV has to be sent through the magnets. Since the injection process using longitudional stacking should not destroy the stored beam, special attention has been paid to the flatness of the current pulse at flat-top ([I-I_0]/I_0<0.08) and to the current variation after ramp down (<10 A). All the challenges of the kicker design have been successfully solved and the kicker system of the HESR has been produced. The system consist of four kicker magnets in two UHV tanks and one solid-state pulser with control system for every magnet. The pulsers, connected with magnet using a coaxial cable in Blumlein topology, are made of commercially available semiconductor based switches. Using a special tuning procedure the designed requirements for the pulse shape have been succesfully met. Main details of the designed system, achieved parametes and solutions used in the produced injection kicker system will be presented in this contribution.

We are developing a fast pulsed power supply using Silicon Carbide (SiC) MOSFETs for a camshaft bunch kicker in KEK-PF. In the kicker system, the pulsed power supply needs to generate a high-precision short pulse with high power. A high repetition rate is also required due to the short circumference of the KEK-PF storage ring of 187 m. Therefore, the target specifications are 500 A pulsed current within a 1% uncertainty, a 100 ns pulse width, a timing jitter of less than 300 ps, a 15 kV voltage resistance, and a 1 MHz repetition rate. In addition, the power supply should have a high radiation resistivity because the power supply will be placed near the accelerator ring to reduce transmission impedance. To achieve the requirements, we have newly started the development of a pulsed power supply with a solid-state switching module using SiC-MOSFETs. We first developed a prototype power supply with a 14 kV switching module consisting of 16 SiC-MOSFETs in series. We confirmed the prototype power supply could deliver half-sine pulses with stable operation at a low repetition rate. The prototype power supply was also tested near the accelerator ring and worked successfully for about two months. We report the performance of the prototype pulsed power supply using SiC-MOSFETs.

Electron beam injection and extraction from the various stages of the SOLEIL II accelerator complex will be performed in three different locations, as it is done today. Injection of the LINAC beam into the upgraded booster and then its extraction use traditional on-axis & on-momentum schemes with single turn kickers and septum magnets*. The main Top-Up injection scheme in the storage ring** will use an off-axis & on-momentum betatron injection scheme. In particular, this scheme requires the design of a new type of Multiple Injection Kicker (MIK) which significantly differs from the current generation. This article presents the technical proposals and design constraints for the pulsed magnets and power supplies – dipole kicker, MIK and septum magnets - foreseen in the upgrade of SOLEIL.

Using a calibrated permanent magnet spectrometer and a streak camera, a time resolved measurement is made for a multi-pulse beam. These measurements are cross calibrated with cell voltage monitors to have a reliable online energy measurement. The Dual Axis Radiographic Hydrodynamic Test Facility (DARHT) Axis-II produces a 16 MeV, 1.65 kA electron beam. Timing on the cell voltages is changed such that the beam has a varying kinetic energy spread. Multi-pulses are produced by a kicker at varying pulse lengths and selecting out different energies from the beam. This paper reports the results of these measurements.

The accelerator upgrades of SLS and Elettra will use newly designed kickers adapted for their small aperture beam pipes. The striplines of the transverse kickers conform closely to the aperture of the beam pipe with special grooves to avoid synchrotron light on the blades. The multitude of trapped higher order modes, caused by a high beam pipe cut-off frequency and dangerous in terms of stability and heat up, is suppressed by lossy silicon carbide dampers. The devices feature integrated pumping ports. The transverse shunt impedance improves by a factor of four compared to the current SLS/Elettra kicker. The longitudinal kicker is a heavily coupled cavity at 1.875 GHz (3.75 * RF) with four input and four output couplers for driver and loads. A nose cone design optimizes the shunt impedance resulting in a 20% improvement over the current SLS/Elettra kicker. Also here, the high cut-off frequency of the beam pipe caused problematic higher order modes, which needed to be damped by higher order mode couplers. A dedicated field sensor pickup will be used to synchronize the feedback to the bunch train.

In the extraction of booster to storage (BTS) for High Energy Photon Source (HEPS), four pulse bump magnets are applied to create a local bump to ease extraction. In this paper, a lot of characteristics of the pulse bump mag-net such as magnetic field, eddy current, induced voltage, vibration are introduced and thoroughly discussed. Ac-cording to measurements, four pulse bump magnets are satisfied with the physical requirements of beams extrac-tion in HEPS.