The utilization of machine learning techniques in accelerator research has yielded remarkable advancements in optimization strategies. This paper presents a pioneering study employing a machine learning algorithm, GPTune, to optimize beam intensity by adjusting parameters within the EBIS injection and extraction beam lines. Demonstrating significant enhancements, our research showcases a remarkable 22% and 70% improvements in beam intensity at two different measurement locations.

Laser Doppler cooled ion traps can produce stationary bunches of ions with extremely low velocity spread (0.6 m/s RMS) and emittance (10e-13 m normalized). This corresponds to temperatures of a few milli-Kelvin and allows the ions to settle into a fixed lattice analogous to a solid crystal, but with the Coulomb repulsion balanced by the trapping force, rather than a chemical bond. Extraction of such a bunch into a beamline could provide a new regime of ultra-low emittance beams if the emittance is preserved through the extraction operation. This paper shows that extraction from the ion trap and initial acceleration does not cause drastic growth, thus preserving the ultra-low emittance nature of the bunch. Techniques for compensating coherent 'emittance growth' effects such as nonlinear bunch distortion are also investigated.

Previously we had developed a new method to fabricate corrugated waveguides (CW) operating in sub-THz frequency regime. As the next step, collaborative effort is underway to demonstrate GW-level high-power sub-THz pulse generation using a CW. We plan to fabricate a CW operating at around 400 GHz. This waveguide will be driven by a bunch train including 16 bunches with nanocoulomb-level charges per bunch. We present an overview of project’s current status.

An ion cloud confined in a Paul trap eventually reaches a Coulomb crystalline state when strongly cooled toward absolute zero. The normalized emittance of the Coulomb crystal can be in the sub-femtometer range. The trap is thus usable as a unique ion source for nano-beam production, though the available beam intensity is limited. This new concept was first discussed nearly 20 years ago* and later experimentally demonstrated by several research groups (**, ***). In this paper, we report on the result of a recent experiment where an attempt was made to extract Ca+ or N2+ ions one by one from a compact linear Paul trap. In addition to the regular extraction scheme based on a string Coulomb crystal, the possibility of using a multi-shell crystalline structure is explored in detail.

Numerical modeling of low-temperature plasma (LTP) ion sources provides cost-effective techniques for developing and optimizing beam characteristics for ion implantation and other applications, including plasma processing and etching. Particle-in-cell (PIC) models are a powerful tool for simulating plasma formation and dynamics in LTP sources. Beam formation and transport of the beam through extraction optics can benefit from reduced physical models. One can couple a PIC model for plasma chambers with a different transport model in the extraction region. However, this coupling is ad hoc, and it is often not clear that the models are physically consistent with each other. We present an integrated modeling capability that couples plasma chamber modeling with beam formation using the VSim computational framework. We leverage advanced modeling techniques such as energy-conserving PIC and variable meshing to improve simulation performance. We present results for modeling and optimization of beams for ion implantation. Our results show that our integrated models can improve optimization of beam currents, beam uniformity, and emittance for LTP ion sources.

Studying the energy deposition in accelerator components, mechanical supports, services, ancillary equipment and shielding requires a detailed computer readable description of the component geometry. The creation of geometries is a significant bottleneck in producing complete simulation models and reducing the effort required will allow non-experts to simulate the effects of beam losses on realistic accelerators. This paper describes a flexible and easy to use Python package to create geometries usable by either Geant4 (and so BDSIM or G4Beamline) or FLUKA either from scratch or by conversion from common engineering formats, such as STEP or IGES created by industry standard CAD/CAM packages. This paper describes the updates to pyg4ometry since IPAC19. These updates include ROOT geometry loading, refactored geometry processing using CGAL, direct CAD file loading using OpenCASCADE, geometrical feature extraction and geometry comparison algorithms. The paper includes small examples of the new features with explanations.

The Super Proton Synchrotron at CERN serves the fixed-target experiments of the North Area, providing protons and ions via slow extraction, and employs the crystal shadowing technique to significantly minimize losses. Over the past three operational years, the use of a crystal, positioned upstream of the electrostatic septum to shadow its blade, has allowed to achieve a 25% reduction in losses. Additionally, a novel non-local shadowing technique, utilizing a different crystal location, has successfully halved these losses. While using a single crystal in this location resulted in a temporary 50% reduction in slow extraction losses at nominal intensity, this effect was not sustainable beyond a few hours. This limitation is primarily attributed to the magnetic non-reproducibility and hysteresis inherent to the SPS main dipoles and quadrupoles. In this paper, we introduce the application of the Rank-Weighted Gaussian Process Ensemble to the setup of shadowing. We demonstrate its superior efficiency and effectiveness in comparison to traditional Bayesian optimization and other numerical methods, particularly in managing the complex dynamics of local and non-local shadowing.

Magnetic hysteresis, eddy currents, and manufacturing imperfections pose significant challenges for beam operation in multi-cycling synchrotrons. Addressing the dynamic dependency of magnetic fields on cycling history is a current limitation for control room tools using existing models. This paper outlines recent advancements to solve this, presenting the outcome of operational tests utilizing data-driven approaches and an overview of the next steps. Notably, artificial neural networks, including long short-term memory networks, transformers and other time series analysis architectures, are employed to model static and dynamic effects in the main dipole magnets of the CERN SPS. These networks capture hysteresis and eddy current decays based on measured magnetic field and data from the real-time magnetic measurement system of the SPS main dipoles. Cycle-by-cycle feed-forward corrections are implemented through the CERN accelerator controls infrastructure, which propagate corrections of magnetic fields to corresponding adjustments in the current of the power converters feeding the magnets.

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.

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 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.

After a long shutdown, the Advanced Photon Source (APS) booster synchrotron was recently re-commissioned for the APS Upgrade (APS-U) project. The APS-U requirements for the booster are more demanding than the old APS: much higher bunch charge, reduced beam emittance, and improved charge stability of better than 5% shot to shot. The booster accelerates electron bunches of 1-12 nC from 425 MeV to 6 GeV at a 1 Hz rep rate. While the booster ring hardware was largely kept the same, it is now run on a separate RF source, which allows for frequency manipulation during the booster ramp. Photon diagnostics have recently been upgraded for reduced thermal drift. This paper will report on the booster re-commissioning process, including checkout of various systems, tests of the new RF source, and tuning for improved performance. It will also detail plans for further improvements, in particular for achieving even higher bunch charge.

To reduce filling times and enable advanced injection schemes, it is desirable for the Diamond-II booster to provide high charge in both single and multi-bunch modes. The single bunch charge will be limited by short range wakefields in the booster, and long-range wakefields limit the charge for the multi-bunch trains. Due to the relatively low 100 MeV injection energy into the booster, the injected beam is susceptible to instabilities due to the very weak synchrotron radiation damping. In this paper, we present the simulation results carried out to estimate the single and multi-bunch charge thresholds in the Diamond-II booster including short and long range wakefields, RF cavity HOMs, and with physical apertures applied. Simulations results will also be presented that demonstrate the extracted multi-bunch charge could be increased by installing a transverse multi-bunch feedback (TMBF).

For several years, significant effort has been spent at GSI to improve the time structure of the spill during slow extraction in SIS18. This led to the requirement to extend the possibilities to experimentally improve the micro-spill structure by partially or fully capturing the beam with an RF of more than 40 MHz. Therefore, a so-called spill-structure manipulation cavity was designed, realized and optimized which allows the mentioned experiments. In this contribution, the design of the cavity and the challenges of its realization are described, and measurement results concerning the first experimental operation in the SIS18 synchrotron are presented.

The LHC Abort Gap Monitor (AGM) is part of the LHC machine protection system (MPS) and is designed to measure the particle population in a 3us wide region known as the "abort gap." This region needs to be kept empty to ensure safe beam dumps. The AGM captures the synchrotron light generated in the visible part of the spectra and converts it into an electric signal. This signal is then processed by an acquisition system and can trigger the ‘abort gap cleaning’ process. The current AGM, which has been in operation since 2010, uses an analogue integrator ASIC and a 40 MHz analogue-to-digital (ADC) converter to provide the particle population information. However, this solution is now considered obsolete and is being replaced by a digital signal processing approach. Working directly in the digital domain not only offers more scalability but also better determinism and reliability. This work presents the new technical solution for the acquisition chain, compares the characteristics of both implementations, and showcases recent measurements conducted on the LHC ion beams.

MedAustron is a synchrotron-based cancer therapy center located in Lower Austria. Patients are treated with proton and carbon ion beams in an energy range of 62-252 MeV/u and of 120-400 MeV/u respectively. The facility features three clinical irradiation rooms, among which horizontal and vertical beam lines as well as a proton gantry are available for treatment. A fourth irradiation room (IR1) is dedicated to non-clinical research activities among which helium ion beams are currently under commissioning. Helium ions are also promising future candidates for clinical treatment due their favorable physical and biological properties. At MedAustron the beam commissioning up to IR1 is near completion. A large energy range (i.e. 39-402 MeV/u) has been commissioned with the support of Monte Carlo simulations performed by the future users. The beam properties in terms of spot size and beam roundness obtained at the isocenter fulfill the user requirements. In this work we present the helium commissioning status with the main focus on the recent results obtained from the commissioning of the synchrotron and transfer line up to the isocenter in IR1.

The High Luminosity Large Hadron Collider (HL-LHC) project seeks to significantly enhance the performance of the LHC to deliver ten times more data to the LHC Experiments. The project relies on cutting-edge systems and technologies deployed in the new facilities constructed to the HL-LHC requisites and replacing large existing equipment and systems in the LHC tunnel. The project complexity lies in the production and installation of innovative systems with strong interdependencies. A methodological schedule management approach is essential to ensure timely equipment delivery, anticipate potential risks and implement mitigation actions. This paper describes the schedule management aspects of the HL-LHC project, providing a robust framework adaptable to any large-scale project. It encompasses the management of the baseline changes, the monitoring of milestones, the planning and coordination of the new facilities installation, and the integration of the HL-LHC installations within the regular LHC maintenance program. Emphasizing the significance of key performance indicators (KPIs), the paper highlights the critical role of metrics as indicators of schedule robustness.

Compact synchrotrons, such as those proposed for cancer therapy, use short and highly bent dipoles. Large curvature drives non-linear effects in both body and fringe fields, which may be critical to control to obtain the desired dynamic aperture. Similarly to current practice, for straight magnet, our long-term goal is to aim at finding a parametrization of the field map that requires few terms to capture the relevant long term dynamical effects. This parametrization will then be used to optimize the performance of the synchrotron by long-term tracking simulations and, at the same time, drive the development of the magnet design by providing measurable quantities that can be computed from field maps. This paper presents the first steps towards the goal of representing the field with a few key parameters.

2023 was the last year of operation for the Cooler Synchrotron (COSY) in Jülich, Germany. To prepare for the extraction of polarized protons at a momentum of 1950 MeV/c to an external target, full advantage of the most recent developments of the COSY control system was taken along with the established hardware of COSY. Challenges in beam development included the operation close to transition energy as well as seven depolarizing resonances (4 intrinsic and 3 imperfection resonances) which have to be crossed during the acceleration. To overcome the intrinsic resonances tune jumps were carried out with the Q-jump quadrupole system of COSY*. To identify the correct time window for the jump, the precise measurement of the tune** during the acceleration ramp was used. We present how the recent developments in the control system, along with the established techniques, enabled us to successfully accelerate and extract the polarized beam.

In SIS18 U²⁸⁺ is used to reach highest heavy ion beam intensities for FAIR-operation. The medium charge state avoids losses during stripping processes and shifts the space charge limit to higher number of particles. Nevertheless, these ions are subjected to ionization loss in collisions with residual gas particles. Via ion impact induced gas desorption a feedback between vacuum quality and beam emerges, yielding in a beam intensity limitation. The installation of a charge exchange collimator is one of the several upgrade measures which have been performed to shift this limit. They are equipped with a current measurement system to detect charge exchanged ions, which is routinely used during machine experiments. In this proceeding we present different beam based measurements showing dynamic vacuum effects. The non-linear dependence of the extraction intensity on the number of injected particles, ramp rate, and brake-time for vacuum relaxation will be shown. Stored heavy ion beams were used for charge exchange current measurements. They allow conclusions on the vacuum conditions and are presented as well.

The bending, quadrupole, and sextupole power supplies in the J-PARC Main Ring (MR) have been upgraded ramping up the average beam power for fast extraction (FX) operation for the neutrino oscillation experiment and slow extraction (SX) operation for the experiments in the hadron facility. The repetition cycles have been shortened from 2.48 sec. to 1.36 sec. for the FX operation and will be soon shortened from 5.2 to 4.24 sec. for the SX operation. The current ripples in the power supply generate the electric current errors of the main magnets. A tracking error can also generate the electric current deviation for the main magnets. A rather large tracking error has been observed after the power supply upgrade. An equivalent circuit analysis for the output load has been conducted to examine the cause. The impact on the beam optics for the longitudinal and transverse beam motions will be discussed. A manipulation of the power supply to improve the tracking errors is tried in the equivalent circuit analysis.

The Los Alamos Neutron Science Center (LANSCE) is one of the oldest operating high-average-power accelerators in the United States, having recently celebrated its 50th anniversary of operation. LANSCE is comprised of an 800-MeV linac capable of concurrently accelerating both H+ and H- ions, and can presently provide beam to six separate user stations. The Proton Storage Ring (PSR) at LANSCE acts as a pulse-stacker, providing intense bunches of protons to the Lujan neutron scattering center target. Critical subsystems have become increasingly difficult to maintain due to spare parts availability; more generally, the PSR contributes significantly to our annual maintenance duration due to beam spill and component activation. The proposed LAMP project would extend the operating lifetime and improve the operational characteristics of the PSR via increasing the physical aperture by 50%; modernizing and improving the performance of the RF buncher system, extraction kickers and impedance inserts; and updating the injection line and stripper foil system for reduced injection losses and improved maintainability. This paper provides an overview of the PSR portion of LAMP.

MedAustron is an ion therapy facility located in Wiener Neustadt, Austria, which uses third order resonant slow extraction to deliver protons and carbon ions for clinical irradiation. The foreseen upgrade of the new low level RF (LLRF) system facilitates advanced longitudinal beam manipulation schemes involving multiple RF harmonics, which will be exploited to improve the slow extraction process and the consequent spill characteristics. To support these studies and provide a new diagnostic tool longitudinal tomography is being implemented. This proceeding presents the employed measurement set-ups and compares the first obtained tomographic reconstructions with BLonD simulations.

Recently, the heavy ion synchrotron SIS18 at GSI was for the first time operated with a dual-isotope beam, made up of 12C3+ and 4He+. Such a beam can be used to improve carbon radiotherapy by providing online information on dose deposition, where the helium ions serve as a probe beam traversing the patient while depositing a negligible dose. For this, the accelerator has to deliver a slowly extracted beam with a fixed fraction of helium over the spill. The difference in mass-to-charge ratio of 4He compared to 12C is small enough to permit simultaneous acceleration and to make the two isotopes practically indistinguishable for the accelerator instrumentation. Yet, it may cause a temporal shift between the two components in the spill owing to the sensitivity of slow extraction to tiny tune variations. We investigated different extraction methods, and examined the time-wise stability of the dual-isotope beam with a beam monitoring setup installed in the GSI biophysics experiment room. A constant helium fraction was obtained using transverse knock-out extraction with adjusted chromaticity.

The CERN Proton Synchrotron Booster (PSB) was upgraded within the LHC Injectors Upgrade (LIU) project and delivers a large variety of high-intensity beams for fixed target experiments and high-brightness beams for collisions at the LHC. In the context of the Physics Beyond Colliders (PBC) study and of a possible upgrade of the ISOLDE experimental area, intensities up to 1500×1e+10 particles per ring are considered. High-intensity tests have thus been performed during machine development studies in 2023 injecting the nominal or higher beam current from Linac4. In this contribution, the intensity reach and the main performance limitations for the production of high-intensity beams in the PSB are presented. The results are compared to numerical simulations.

Fixed target beams are extracted in five turns from the Proton Synchrotron (PS) at CERN to fill almost half the circumference of the Super Proton Synchrotron (SPS) with each transfer. To avoid beam loss during the risetime of the extraction kickers a longitudinal gap is generated with an RF barrier-bucket scheme. However, the synchronization of the gap with the PS extraction and SPS injection kickers requires the RF system to operate without any beam feedback during the transverse splitting process at the flat-top. Low RF voltage is moreover required during the process to keep a small momentum spread. Both conditions are unfavorable for longitudinal stability and a campaign of beam measurements has been performed to explore potential intensity limitations. Up to 3.3e+13 protons have been accelerated and remained longitudinally stable at high energy. Longitudinal coupled-bunch instabilities occurring at the intermediate plateau below transition energy are moreover cured by a dipole-mode feedback system initially developed for LHC-type beams. The contribution summarizes the results of the beam tests, probing the limits of the fixed-target proton beam production.

The CERN Super Proton Synchrotron (SPS) offers slow-extracted, high-intensity proton beams at 400 GeV/c for 3 fixed targets in the CERN North Experimental Area (NA) with a spill length of about 5 seconds. Since first commissioning in the late seventies, the NA has seen a steady increase in users, many of which requiring improved spill quality control. Slow extraction is sensitive to small perturbations with the effect of reduced spill quality. While some of these effects have been addressed in recent years, continuous compensation of intensity fluctuations at 50 Hz harmonics originating from power converter ripple has been particularly difficult to achieve. In 2023, the deployment of two techniques - "Empty-Bucket Channeling" and active control with Adaptive Bayesian Optimization – resulted in a significant suppression of these intensity modulations. This paper focuses on using Adaptive Bayesian Optimization for 50 Hz harmonic control. The chosen algorithm is described, together with details of integration in the CERN control system. The 2023 results are presented and complemented with an overview of the next steps.

During the operation of the Continuous Electron Beam Accelerator Facility (CEBAF), one or more unstable superconducting radio-frequency (SRF) cavities often cause beam loss trips while the unstable cavities themselves do not necessarily trip off. The present RF controls for the legacy cavities report at only 1 Hz, which is too slow to detect fast transient instabilities during these trip events. These challenges make the identification of an unstable cavity out of the hundreds installed at CEBAF a difficult and time-consuming task. To tackle these issues, a fast data acquisition system (DAQ) for the legacy SRF cavities has been developed, which records the sample at 5 kHz. A Principal Component Analysis (PCA) approach is being developed to identify anomalous SRF cavity behavior. We will discuss the present status of the DAQ system and PCA model, along with initial performance metrics. Overall, our method offers a practical solution for identifying unstable SRF cavities, contributing to increased beam availability and facility reliability.

In the context of research on simultaneous heavy ion radiotherapy and radiography, a mixed carbon/helium ion beam has been successfully established and investigated at GSI for the first time to serve fundamental experiments on this new mode of image guidance. A beam with an adjustable ratio of 12C3+/4He+ was provided by the 14.5 GHz Caprice ECR ion source for subsequent acceleration in the linear accelerator UNILAC and the synchrotron SIS18. Despite the mass difference between the 4He+ and 12C3+ ions, both could be slowly extracted simultaneously at 225 MeV/u using the transverse knock-out extraction scheme. The ion beam has been finally characterized in the biophysics cave in terms of beam composition (particularly inter- and intra-spill He fraction), depth-dose-profiles, beam size, position and other parameters, all related to combined ion beam treatment and online monitoring. Utilizing high-speed particle radiography techniques, a fast extracted mixed ion beam has also been characterized in the plasma physics cave under conditions favorable to FLASH therapy.

The Main Ring (MR) at J-PARC (Japan Proton Accelerator Research Complex) is a proton synchrotron that accelerates protons from 3 GeV to 30 GeV. One of the two MR's extraction modes is slow extraction using third-order resonance toward the Hadron Experimental Facility, where various particle and nuclear physics experiments are conducted. There are two major points in the slow extraction: beam loss reduction and flat spill structure of the extracted beam. In the beam operation of 2021, we achieved a beam power of 65 kW with a high extraction efficiency of 99.5% and a spill duty factor of 60%, but requirements for further improvements from physics experiments have never stopped. From 2021 to 2022, various devices in the MR were upgraded. The primary purpose of this upgrade was to increase the beam power by shortening the acceleration time and increasing the repetition rate. To achieve this goal, we rebuilt most parts of the main magnet power supplies. The new power supplies are also expected to be significantly improved in the current ripple. Thus the time structure of the slow extracted beam is also expected to be greatly improved. In addition, plans are underway for further reduction of the beam loss through the use of beam diffusers and bent silicon crystals and for improvement of the spill structure by feedback algorithms reconstruction. This talk presents the status of the MR and the prospects of the slow extraction after the MR upgrade.

Schottky monitors are valuable non-invasive tools used for beam diagnostics, providing insights into crucial bunch characteristics such as tune, chromaticity, bunch profile, or synchrotron frequency distribution. This study investigates Schottky spectra at the Large Hadron Collider (LHC) through a combination of simulations and measurements. Experimental data from lead ion bunches are compared with simulated spectra derived from time-domain, macro-particle simulations. In particular, amplitude detuning due to the octupole magnets, known to influence the Schottky spectra, is incorporated into the simulations. These simulations are performed for various octupoles currents with the goal of better understanding the interplay between octupoles and the Schottky spectrum. Finally, measured spectra are compared to simulations performed using the best available knowledge of the parameters impacting the spectra.

Schottky monitors serve as non-invasive tools for beam diagnostics, providing insights into crucial bunch characteristics such as tune, chromaticity, bunch profile, or synchrotron frequency distribution. However, octupole magnets commonly used in circular storage rings to mitigate instabilities through the Landau damping mechanism, can significantly affect the Schottky spectrum. Due to the amplitude-dependent incoherent tune shift of individual particles, the satellites of the Schottky spectrum are smeared out as the octupolar field increases. This study investigates the impact of octupoles and their incorporation into theory, with the goal of improving beam and machine parameter evaluation from measured spectra. Theoretical findings are validated through macro-particle simulations conducted across a range of octupole strengths, encompassing typical operational conditions at the Large Hadron Collider.

The measurement of beam emittances by extracting the quadrupole mode signal from a 4 plate BPM was published at least 40 years ago. Unfortunately, in practice, this method suffers from poor signal to noise ratio and requires a lot of tuning to extract out the emittances. In this paper, an improved method where multiple BPMs are used together with better mathematical analysis is described. The BPM derived emittances are then compared with those measured by the Ion Profile Monitor (IPM). Surprisingly, the BPM measured emittances behave very well and are more realistic than those measured by the IPM.

Cryogenic Current Comparators (CCC) are ultrasensitive DC-Beam Transformers based on superconducting SQUID technology. With the aim to provide a robust and high resolution intensity measurement for application at FAIR and CERN machines, numerous steps of optimization were carried out over the last years by a collaboration of institutes specialized on the various subtopics. Different types of CCCs with respect to pickup, magnetic shielding, SQUID types and SQUID coupling have been developed and were tested in the laboratory as well as under beamline conditions. In parallel, the cryogenic system has steadily been optimized, to fulfill the requirement of a standalone liquid helium cryostat, which is nonmagnetic, fit for UHV application, vibration damped, compact and accessible for maintenance and repair. We will present the particular development steps and describe the final version of the CCC for FAIR as their outcome. The latest beamtime results are shown as well as recent tests with the cryogenic system. The CCC for FAIR will be a so called Dual-Core CCC (DCCC), which runs two pickups in parallel with independent electronics for better noise reduction and redundancy. The magnetic shielding will have an axial meander geometry, which provides superior attenuation of external magnetic noise.

In-vivo dosimetry is essential to deliver precise doses to patients in ion beam therapy. Real-time dose monitoring without disturbing the beam improves patient safety and treatment efficiency. It is critical for emerging treatment modalities like FLASH therapy due to the narrow dose tolerance. Existing real-time dosimetry devices are invasive to beam, necessitating a non-invasive dosimetry solution. The gas-jet based beam profile monitor developed at the Cockcroft Institute (CI) is being studied for application in medical accelerator facilities. Recent measurements at the Dalton Cumbrian Facility, UK yielded promising results for beam monitoring at energies equivalent to medical beam. These studies have indicated the need to improve the gas-jet based Ionization Profile Monitor (IPM) to monitor dose in real time. A new IPM detector system is under development at CI to reduce the monitor size and complexity, and increase its sensitivity, resulting in fast acquisition, paving the way for real-time in-vivo dose monitoring. This contribution presents the design of the optimized IPM and its working principle based on electrostatic field and particle trajectory simulations.

Following the LHC Injectors Upgrade (LIU) project at CERN, the Proton Synchrotron Booster (PSB) has been upgraded to operate with a new injection kinetic energy of 160 MeV and an extraction energy of 2 GeV. To understand the performance of the accelerator in this new energy range, a series of measurements have been conducted, especially devoted to the beam stability to ensure the optimal operation of the machine. A horizontal instability, firstly observed in 2021 at about 1.6 GeV (between the old and the new extraction energy of the Proton Synchrotron Booster), has undergone in-depth investigation in measurements. Despite the identification of a mitigation strategy to cure the horizontal instability, efforts have also been focused to understand its source. The results have once again drawn the attention to the termination of the extraction kicker. As happened in 2018, a dedicated MD performed at the end of 2023 run with matched kicker termination confirmed the impact of the extraction kicker in this instability.

The AGS-RHIC injector complex includes H- ion sources at 35 keV, 750 keV RFQ and 200 MeV Linac. This report will focus on the recent upgrade of the 35 KeV Low Energy Beam Transport (LEBT) with three sources: two high-intensity magnetron H- sources and an Optically Pumped Polarized Ion Source (OPPIS) polarized H- source. There were still significant beam intensity losses in the 8 m long OPPIS transport line due to H- stripping, therefore, to meet the demand for the higher beam intensity in the 2024 polarized run, the OPPIS LEBT length was reduced by about two meters. Another possibility for increasing beam intensity is to increase the beam pulse width. The sources performance and operation in Run-2024 will be presented.

The main challenge in the development of high intensity ion sources is, besides the space charge limited extraction, the available plasma density. Conventional plasma generators use e.g. arc discharge plasmas or RF generated plasmas. Preliminary tests are carried out on both types of plasma generators and plasma parameters are determined to create a basis for evaluation. A concept is being developed that combines the advantages of both types. This hybrid plasma generator will also be investigated in terms of plasma parameters in order to test a possible application for high intensity ion sources. Further the proposed plasma generator has the property that due to a permanently available low-density RF plasma a faster build-up of the highly dense arc discharge plasma may be achieved. The properties of the concept with regard to a fast plasma build-up time are being investigated in order to test a possible application for the fast pulsing of high intensity ion sources.

We propose and demonstrate a time-resolved, two-dimensional temperature monitoring technique for nanocrystalline diamond stripper foils exposed to high-intensity hydrogen ion (H-) beams at the Spallation Neutron Source (SNS) accumulator ring which is independent of foil emissivity. The technique utilizes a two-color imaging pyrometer in the shortwave infrared (SWIR) spectral band to measure thermal radiation from stripper foils located 40 meters away from the measurement site. This work presents a unique optical design, optical calibration of the system using a high-temperature blackbody source, preliminary temperature measurement results from two stripper foils (new and used) under various H‒ production beam conditions with average powers up to 1.7 MW and energy of 1.0 GeV. This technique can be utilized to understand the thermal behavior of charge strippers under high-intensity particle beams, providing crucial feedback to operations to control foil temperature and ensure foil lifetime.

Within the LHC Injectors Upgrade (LIU) project, the LHC injectors received major upgrades that resulted in an unprecedented brightness performance. In the framework of the Physics Beyond Colliders (PBC) study, the full potential of the upgraded injectors is being explored for the improvement of the Fixed Target (FT) beams as well. This contribution details the recent studies on the beam transmission and beam quality along the injectors of the SPS Fixed Target PROton (SFTPRO) beams that reach the North Area (NA) experiments. In particular, the possibilities for tailoring the transverse emittances out of the PSB and the impact on the beam transmission in the SPS are shown. Furthermore, the impact of the transverse damper excitation on the efficiency of the Multi-Turn-Extraction in the PS are discussed. Finally, the main factors that limit the intensity reach of the injectors are also discussed.

Integrable systems possess a hidden symmetry associated with the existence of conserved quantities known as integrals of motion. These systems play an important role in understanding general dynamics in accelerators and have potential for future designs. This work will cover two automated methods for finding integrable symplectic maps of the plane. The first algorithm is based on the observation that the evolution of an integrable system in phase space is confined to a lower-dimensional submanifold of a specific type. The second algorithm relies on an analysis of dynamical variables. Both methods rediscover some of the famous McMillan-Suris integrable mappings and ultra-discrete Painlev\'e equations. Over 100 new integrable families are presented and analyzed, some of which are isolated in the space of parameters, while others are families with one parameter (or the ratio of parameters) being either continuous or discrete. In addition, the newly discovered maps are related to a general 2D symplectic map through the use of discrete perturbation theory. A method is proposed for constructing smooth near-integrable dynamical systems based on mappings with polygon invariants.

The Los Alamos Neutron Science Center (LANSCE) accelerator delivers high intensity proton beams for fundamental science and national security experiments since 1972. The Proton Storage Ring (PSR) accumulates a full 625-us macro-pulse of proton beam and compresses it into a 290-ns long pulse, delivering an intense beam pulse to the Lujan Neutron Science target. The proposed LANSCE Modernization Project (LAMP) is evaluating necessary upgrades to the accelerator that will guarantee continuous beam operations in the next decades. Upgrades to the PSR and its high-energy injection and extraction beamlines are being considered to handle the higher beam intensity enabled by the LAMP upgrades in the front-end. For the PSR upgrades studies, we are building models of the PSR injection and extraction lines in codes which include space charge calculations like Elegant and Impact. These better illustrate the beam dispersion and the beam halo in the high-energy transport. This work describes the LANSCE PSR injection and extraction lines and the corresponding simulation models. The models are compared to available beam diagnostics data where available.

The SLRI Beam Test Facility (SLRI-BTF) is able to produce electron test beam with maximum energy of 1.2 GeV and various intensities from a few to millions of electrons per repetition. The main components of the SLRI-BTF are the Siam Photon Source (SPS) injector consisting of a 40-MeV linear accelerator, a low-energy transport beamline, a synchrotron booster increasing electron energy to 1.2 GeV, and a high-energy transport beamline. As the SLRI-BTF has successfully utilized the electron test beam to characterize pixel sensors for high-energy particle detectors and to perform high-energy electron irradiation, the test beam with lower energy ranges has also been requested by users. In this work, the test beam with lower energy can be obtained by changing the acceleration pattern of the SPS booster and adjusting high-energy transport beamline to match the extracted beam energy. Production of test beam with lower energy can be confirmed by test beam measurement at the SLRI-BTF experimental station.

The Full Remote Alignment System (FRAS) is an alignment system remotely controlled and monitored that comprises almost one thousand permanent sensors distributed along the 200 meters of equipment that will be installed in the frame of the High Luminosity LHC (HL-LHC) project on either side of the ATLAS and CMS detectors. The sensors, along with their electronics and a system of motorized actuators, will be used to adjust the relative positions of the components remotely, in real time, with no human intervention needed in the irradiated environment of the tunnel. In this contribution we describe the design and the implementation of the position estimation algorithm which is a core-component of the FRAS. This algorithm will process the data provided by all the sensors to determine exact positions and orientations of the associated components in real-time. The position estimation module is designed as a reusable C++ library and builds on the existing CERN LGC, a modular least-square software. It will be fully integrated into the FRAS software stack and is entirely file-less during operation. In this paper we will demonstrate its performance in a realistic case study and showcase its ability to provide position updates on a much higher frequency than the required 1 Hz.

The J-PARC MR synchrotron began high repetition operation with shortened accelerator cycles in 2022. So far, FX has been supplying a 2x10e+14 proton per pulse (ppp) beam to the Neutrino Experimental Facility with a repetition rate of 1.36 seconds, and SX has been supplying a 0.6x10e+14 ppp beam to the Hadron Experimental Facility with a 5.20 seconds repetition. The amount of heat per accelerated proton beam pulse exceeds 1 MJ, and it is an important issue to avoid damage to the equipment caused by high-intense beam due to abnormalities during beam acceleration. Since the MR is operated in different extraction modes, i.e. FX and SX, the countermeasures are also different, and the adequate protection system also needs to be considered, respectively. Therefore, the countermeasures have been put in place, including a high-speed beam abort system and/or a fast sequential interlock between devices. This report summarizes the systems to protect equipment from abnormalities that unexpectedly occur during high-intensity proton beam acceleration.

The experience gained at CERN by the R&D for LINAC4 has been exported to medical and societal applications. With an innovative design of the Radio Frequecy Quadrupole (RFQ) at high frequencies, it is possible to build very com- pact structures, reproducible in industry and with the po- tential of full portability. ELISA (Experimental LInac for Surface Analysis) is a linear proton accelerator installed in the Science Gateway exhibition at CERN since October 2023. With a footprint of only 2×1 square meters, ELISA consists of an ion source, a one-meter-long RFQ working at 750 MHz and an analysing line dedicated to Particle Induced X-ray Emission (PIXE). The system can accelerate a proton beam (extracted from the source at 20 keV) up to an energy of 2 MeV. In this paper the ELISA source commissioning is presented, with a multi-parameter optimization performed both computationally and experimentally and the ultimate optimization of beam emittance at 20 keV, finally achieving the required brilliance of the source. High energy beam com- missioning will also be discussed, including RFQ voltage scan to study the transmission and characterize the ELISA RFQ.

The Bonn Isochronous Cyclotron provides proton, deuteron, alpha and other light ion beams with a charge-to-mass ratio Q/A >= 1/2 and kinetic energies ranging from 7 to 14 MeV per nucleon. The beam is guided through a high-energy beam line (HEBL) to one of five experimental sites. The installation of the irradiation site for high-uniformity radiation hardness tests of Si detectors is now complete. Additionally, a neutron irradiation site will be commissioned soon. Here, a collimated neutron beam, generated by a stripping reaction of the deuteron beam in a carbon target, can be used for irradiation. To provide stable beam with constant optics for these experiments, the power supplies (PS) of all magnets in the HEBL will be replaced. The replacements must meet strict criteria regarding output current's stability, which were derived from measurements of the existing PS. In this spirit, a new corrector magnet PS system, enabling bipolar operation, PS/magnet operation safety/health and power consumption monitoring, is close to commissioning. Additionally, the cyclotron's extraction septum is upgraded to increase operation robustness. Here, an new antiseptum is designed together with a new septum blade holder, which is intended to be additively manufactured with the laser- powder bed fusion technique.

Testing of space-bound microelectronics plays a crucial role in ensuring the reliability of electronics exposed to the challenging radiation environment of outer space. This contribution describes the beam optics studies carried out for the run held in November 2023 in the context of the CERN High-Energy Accelerators for Radiation Testing and Shielding (HEARTS) experiment. It also delves into an investigation of the initial conditions at the start of the transfer line from the CERN Proton Synchrotron (PS) to the CERN High Energy Accelerator Mixed-field (CHARM) facility. Comprehensive optics measurement and simulation campaigns were carried out for this purpose and are presented here. Using a validated optics model of the transfer line, the impact of air scattering on the beam size was quantified with MAD-X and FLUKA, providing valuable insights into the current performance and limitations for Single Event Effects (SEE) testing at CHARM.

Radio Frequency Knock Out (RF-KO) resonant slow extraction is commissioned at the Cooler Synchrotron (COSY) Jülich for the first time to extract the stored beam and deliver spills with constant particle rates to the experiments. Therefore, transverse RF excitation generated with a software-defined radio is applied to control the extraction rate. A built-in feedback system adjusts the excitation amplitude to maintain the desired extraction rate. To suppress fluctuations of the particle rate on timescales of milliseconds and below, an optimization algorithm is used to tune the RF excitation signals. The method was used extensively during the final run of COSY in 2023, reliably delivering stable beams to various users.

The following paper embarks on an in-depth exploration of extraction kickers employed at some of the most renowned particle physics and neutron science facilities worldwide. Specifically, we delve into the extraction kickers utilized at the Spallation Neutron Source, Fermi National Accelerator Laboratory, Los Alamos Neutron Science Center, and delve into the novel inductive adder structures. These facilities represent the forefront of scientific research, housing state-of-the-art technologies and extraction kicker systems that play a fundamental role in advancing our understanding of particle physics, neutron science, and related domains. Throughout the paper, we will investigate the design principles, operational intricacies, and technological innovations associated with these extraction kickers. By analyzing existing research and scholarly works, we aim to provide a comprehensive overview of the unique challenges and advancements encountered at each facility.

The temporal characteristics of ultra-high dose rate beams delivered for FLASH research are often dictated by machine constraints, making it challenging to compare the outcomes across studies performed at different facilities. To broaden the opportunities for systematic, non-clinical FLASH research, this study explores methods to deliver beams with customizable time structures from a medical synchrotron. The studies are being performed at the center for ion beam therapy and research MedAustron and aim at extracting ultra-high dose rate proton beams in a series of pulses with adjustable dose per pulse, pulse length and pulse separation down to sub-ms levels. This contribution describes the implementation of the extraction methods explored for this application, phase displacement and radio frequency knockout extraction, and presents first measurement results. The measurement setup employs a silicon carbide detector in conjunction with a 20 MHz bandwidth amplifier, enabling intensity measurements with a resolution exceeding the synchrotron revolution period.

In recent years, mixed helium and carbon ion irradiation schemes have been proposed to facilitate in-vivo range verification in ion beam therapy. Such a scheme proposes to deliver both ion species simultaneously, with the idea of performing the treatment with carbon ions, while exploiting helium for online dosimetry downstream of the patient. The center for ion beam therapy and research MedAustron supplies protons and carbon ions for clinical treatment. It is currently being commissioned to additionally provide helium ions for non-clinical research, opening the opportunity for exploring the feasibility of mixed beam irradiation. A key aspect in this context is the slow extraction of the ion mix, which is affected by the relative charge-to-mass ratio offset between the two ions of approximately 6e-4. This contribution analyses differences in the transverse phase space and tune distributions of the two ion species and subsequently discusses first simulation results of the extraction process.

Bent crystals are a mature technology used in several applications at CERN, such as the crystal-assisted collimation system for LHC ion operation and reduction of losses during the slow extraction from the SPS by shadowing the electrostatic septum. In the future, it is planned to measure electric and magnetic dipole moments of short-lived particles with a double-crystal experiment in the LHC. To consolidate their strategic use, CERN has been equipped to produce in-house bent crystals. Each crystal is required to be fully validated before its installation by different techniques, such as metrology, X-ray diffractometry and characterization with beams. The latter can measure the bending angle, the torsion, and the channeling efficiency, which is related to crystal imperfections. In this contribution, we present the performance with beams of the first prototype bent crystals manufactured at CERN and tested during a measurement campaign in the North Area.

Designed as an internal tool at CERN, PLAN has a pivotal role in the centralization and macroscopic aggregation of technical intervention and enhancement activities planned within the accelerator complex. As part of a broader strategy to enhance tool utilization and extract valuable insights, a substantial endeavor during RUN3 aimed to develop and disseminate analytics derived from tool-generated data. These analytics are seamlessly accessible via a FLASK application, crafted primarily using Python and the Bokeh library, JavaScript, HTML, and CSS. Hosted internally at CERN through OpenShift, it is containerized through Docker, and subject to continuous integration via GitLab. These analytics serve versatile purposes, encompassing the quantification of activities, identification of resource constraints across departments and groups, and the provision of insights into various facilities, projects, and more. Moreover, they play an instrumental role in identifying bottlenecks and critical milestones in planning timelines. These analytics are designed to furnish management and other stakeholders with essential insights, ultimately contributing to wide-ranging improvements across CERN.

The world's smallest carbon ion treatment facility has been commissioned at Yamagata University. The treatment system consists of an ECR ion source, a linac cascade of 0.6 MeV/u RFQ and 4 MeV/u IH-DTL, a 430 MeV/u slow extraction synchrotron, and irradiation systems of a fixed horizontal beamline and a compact rotating gantry using superconducting combined function magnets. The size of the building is 45 x 45 m, realized by placing the irradiation rooms not on the same level as the synchrotron, but above it, connected by a vertical beam transport. The most advanced accelerator technology of this machine is to control the beam range up to 300 mm in 0.5 mm steps without any physical block range shifter. To achieve this range step, 600 beam energies were provided in the synchrotron and in the beam transport and tuned to control the beam size in the treatment room. Initial commissioning and daily/monthly quality assurance were carried out by interpolation of beam energy and gantry angle. After tuning the beam size and correcting the beam axis in the treatment rooms, precise dose measurement was performed for clinical irradiation. After the clinical commissioning, the facility started treatment irradiation in February 2021 with a fixed beam port and in March 2022 with a gantry beam port. After March 2023, the gantry angle was operated with a 15-degree step. By November 2023, 1330 patients had been treated.