Beam halo formation is a significant challenge for high-intensity accelerators, as it can lead to performance degradation and radiation safety risks. This study investigates the formation and mitigation of beam halos caused by a picosecond time-delayed laser pulse, which generates a secondary electron bunch in the same RF bucket as the main bunch. The energy difference between the two bunches creates a defocusing effect, leading to the halo generation. Experimental validation of RF-Track simulations was conducted at the AWAKE Run 2c test injector (ARTI). The research outlines methods for identifying, analyzing, and mitigating laser-driven beam halo formation, contributing to more effective control of beam halos in accelerator operations.

Symplectic simulation of space-charge effects is important for high-intensity particle accelerators. In this work, we propose to use a generative model to efficiently simulate space-charge effects in JuTrack, a Julia-based particle tracking code. The one-step symplectic transverse transfer map of the particles is obtained by differentiating the predicted space-charge Hamiltonian. This model effectively preserves the phase-space structure and reduces non-physical effects in long-term simulations by ensuring symplecticity in the calculation.

The components of the SIS100 synchrotron (FAIR facility) are presently under installation in the accelerator tunnel. The superconducting dipole magnets have been produced and the magnet field errors up to 7th order have been measured for all magnets. The superconducting quadrupole magnets are under production, the field error data for a part of the magnets is available. As a part of the magnet quality assessment, the particle tracking simulations are used to study the beam losses during the 1 sec beam accumulation at the injection energy. The tune settings for the slow extraction operation are considered. Direct space-charge effects and the Landau damping octupole magnets, which dominate the incoherent tune distribution, are included. In order to reduce the computational load and to increase the parameter resolution, a machine learning based optimizer is used in the accelerator and beam parameter studies.

This study explores beam dynamics in the development of high intensity cyclotrons, focusing on the challenges posed by space charge effects at high beam intensities. Space charge forces, which become significant in high-current operations, can lead to emittance growth, beam loss, and instability, compromising cyclotron performance. Advanced modeling techniques are employed to analyze and mitigate these effects, ensuring stable beam transport and acceleration throughout the cyclotron. By optimizing field configurations and beam trajectories, the study achieves improved beam quality and reduced particle losses. These findings contribute to the development of cyclotrons capable of delivering high-intensity beams for applications such as BNCT.

SKIF (Russian acronym for Siberian Circular Photon Source) – is a new fourth generation synchrotron light source under construction in Novosibirsk, Russian Federation. One of the most important characteristics of the synchrotron radiation source SRF "SKIF", which in turn determines its brightness, is the ultra-low emittance of the electron beam, which depends on the operating regime and parameters of the storage ring: the intensity of the electron beam, the insertion devices parameters, the coupling coefficient of linear betatron oscillations, the elongation of the bunches, etc. Intrabeam scattering (IBS) is a collective effect that causes bunch volume inflation and brightness decrease for high intensity beams. Described in this work are the results of study of IBS impact on beam emittance, energy spread, Touschek lifetime and geometrical brightness for different operating regimes of the SRF “SKIF” storage ring.

Space charge effects in combination with betatron resonances limit the performance of high-brightness LHC beams in the CERN Super Proton Synchrotron (SPS). Here we report on experimental studies performed with single-bunch proton beams, monitoring transverse emittance evolution and particle losses while performing tune scans across the horizontal and vertical planes. Two significant resonances were identified: a coupled resonance leading to emittance growth in the horizontal plane and a corresponding emittance decrease in the vertical plane, and another coupled resonance directly associated with particle losses. The resonances identified in these studies could explain the limitations of the beam brightness encountered with the multi-bunch LHC-type beams in the SPS, thus providing valuable insights for the optimization of the high-intensity beams performance.

The transverse beam halo population in the Large Hadron Collider (LHC) has been found to carry a significant fraction of the total stored beam energy, potentially reaching several percent. With the anticipated increase in beam brightness for the High Luminosity LHC (HL-LHC), this poses an increasing risk to machine safety, particularly during abrupt orbit shifts or critical component failures. A comprehensive understanding and an accurate modelling of the transverse beam halo are crucial for simulations of beam losses around the ring as a consequence of such failure scenarios in the HL-LHC era. Various models, including Gaussian, double-Gaussian, and q-Gaussian distributions, have been used to describe the LHC beam halos for fitting the measured distributions. This paper provides an in-depth analysis of halo modelling based on collimator scraping measurements from the LHC operational Run 2 and Run 3, and evaluates the accuracy and representativeness of these different distribution models.

Measurements of the transverse beam-halo population at large amplitudes in the Large Hadron Collider (LHC) provide crucial insights into the stored beam energy near the LHC collimators. These particles do not contribute significantly to the luminosity but their loss could impose limitations on accelerator performance through sudden loss spikes or even collimator damage in case of fast beam failures. A thorough understanding of the beam halo formation, along with the physical mechanisms driving its behaviour and evolution throughout the final stage of the LHC injection chain and during the acceleration cycle, is essential to define appropriate mitigation strategies to ensure reliable operation in view of High Luminosity LHC beam parameters. In this study, we explore potential origins of the transverse beam halo by examining experimentally multiple contributing factors to halo formation, including electron cloud effects, beam injection dynamics from the Super Proton Synchrotron (SPS), and the energy ramping process within the LHC.