Off-momentum losses at the start of the LHC acceleration ramp in proton runs gave rise to multiple beam dumps by exceeding Beam Loss Monitor (BLM) thresholds in the momentum cleaning insertion (IR3). Accurately estimating the power deposition profiles in IR3 is necessary to determine where BLM thresholds can be optimized, thereby reducing unnecessary beam dumps and improving machine availability and performance. Understanding the loss limits in IR3 is crucial for future High-Luminosity LHC (HL-LHC) performance. In this study, we present FLUKA power deposition results and introduce a newly developed simulation model for BLM benchmarking in IR3. We provide a comprehensive overview of the power deposition in magnets and collimators, identifying potential bottlenecks in the system. Our simulations were benchmarked against multiple fills from 2023 and 2024 that led to beam dumps. The obtained results provide a deeper understanding of the IR3 collimation performance in view of HL-LHC operation in IR3.

Every high-energy beam dump event at the Large Hadron Collider (LHC) is analysed to assess the performance of the machine protection system and to identify anomalous behaviour. Analysing the loss pattern of nearly 4000 beam loss monitors, which depends on beam parameters and machine settings, can be time-consuming and requires expert knowledge. Therefore, an automated beam loss analysis tool was developed and deployed in operation in November 2023. It uses empirically derived beam loss thresholds that scale with relevant beam parameters to evaluate beam dumps for post-mortem analysis. The paper describes how the beam loss thresholds were derived and optimised and reviews their performance in proton and Pb-ion operation.

The Future Circular lepton Collider (FCC-ee) will be an e+e- collider with beam energy spanning from 45.6 GeV to 182.5GeV. When operating in Z-mode, it will deliver the highest luminosity ever obtained in any lepton machine worldwide, and the stored beam energy will reach up to 18 MJ. Due to synchrotron radiation damping, the beam vertical size will be on the order of a few tens of um corresponding to a maximum energy density of ~5 GJ/mm^2 in the collider ring. A dedicated beam dumping scheme is required to safely dispose this potentially disruptive beam. A transfer line is designed to increase the beam transverse size as much as possible and reduce the energy density of the beam at the dump. This contribution presents the dump transfer line design for the collider ring as well as related studies on machine protection.

To understand the risk of damage to the collimator blades and the permanent magnets in Diamond-II, the BDSIM code has been used to model the beam losses. To improve the accuracy, the engineering model and 3D field maps have been used to build the machine model. Energy deposition in the main storage ring components and the fluence of secondary particles (particularly neutrons) have been determined. This paper explains the simulation process and give the BDSIM tracking results.

CERN’s Future Circular Collider (FCC) comprises a ~91 km circumference lepton collider and its injector complex. This contribution summarises the feasibility studies performed for the various kicker systems needed to transfer the beam between the different machines. The individual system requirements are reviewed, recent changes are highlighted, and the chosen conceptual design is outlined. Particular effort has been made to harmonise the hardware parameters across the machines to minimise the number of different beam line element types. The feasibility of the design parameters and technology options is discussed for both beam line elements and pulse generators. Early system integration aspects and implications on subsystems such as pulse transmission cables are also discussed. Consequences of the more restrictive requirements on the abort gap length in the collider are analysed. This contribution concludes with recommendations for detailed studies and prototyping required to ensure a viable parameter space for the upcoming detailed technical design phase.

Slow beam the extraction in synchrotrons is utilized for various nuclear and particle physics experiments and radiology. A beam loss at a septum electrode induces equipment activation and damage. We have been developing a non-destructive electrostatic septum. This septum has multiple electrodes, and those are placed around the outside of the beam. Measuring the 2-D electric field distribution of this septum is important to evaluate the beam loss reduction due to this septum. We are developing the beam separation test device consists of a prototype septum, horizontal and vertical wire scanners and the electron gun installed on a movable stage fixed to a drive unit. This device measures the electric field by injecting an electron beam into the electric field and measuring the bending angle of the beam orbit. Since the width of the electron beam determines the resolution of the measurement data, we developed an additional lens system that can transport the beam 1.5 m with a width of 1 mm. We used a square chamber for the 2-D measurement system. A permalloy magnetic shield is installed inside the chamber and reduces the external magnetic field from 50 $\mu$T to less than 1.5 $\mu$T.

The Swiss Light Source (SLS) at the Paul Scherrer Institute (PSI) was Switzerland’s first and only 3rd-generation light source. For the SLS 2.0* upgrade the old 2.4 GeV, 12-fold 3-bend achromat lattice with 5 nm horizontal emittance was decommissioned in September 2023 after 22 years of successful user operation. The new 2.7 GeV storage ring has a 12-fold 7-bend achromat lattice achieving 150 pm horizontal emittance. Injectors remain mostly unchanged: the 100 MeV linac feeds the 3 Hz booster synchrotron with extraction at 9 nm horizontal emittance and now 2.7 GeV to match the storage ring’s increased energy. Technical details and an overview of the SLS 2.0 commissioning are presented in separate contributions to this conference. This contribution focuses on the machine protection system challenges for the SLS 2.0**. These required the implementation of a sophisticated system including a fast beam dump kicker, dedicated beam dump, fast beam dump controller and a machine interlock system monitoring over 6000 signals. We discuss challenges encountered and lessons learned while commissioning this advanced machine protection system in parallel to commissioning of the new accelerator.

The 5 MeV beamline of Phase B+ which is an intermediate commissioning stage of the Linear IFMIF Prototype Accelerator (LIPAc) consists of an MEBT, an MEBT Extension Line (MEL) where the SRF will be installed, a HEBT, and a beam dump. It has 17 quadrupole magnets, and some quads have small aperture-to-length ratios and are also densely installed in the MEBT and HEBT sections. In the early stages of Phase B+, we optimized the beam optics with the conventional hard-edge model for all the quads. However, we observed unwanted particle losses and discrepancies in the rms beam sizes between measurements and simulations due to significant fringe fields and magnetic interference. After considering the field maps and the magnetic interference of the quads in the beam optics, we could obtain the matching beam and reduce the particle losses. In this paper, we characterize the beam optics by comparing the transfer matrices with and without the fringe fields and the interferences using a conventional hard-edge model and a more accurate hard-edge model equivalent to the field maps.

Beamstrahlung radiation represents a new challenge at CERN's lepton Future Circular Collider (FCC-ee), specifically for electron-positron collisions. At each interaction point, its unprecedented beam intensities give rise to two photon beams with a power of several hundred kW each. Liquid lead, known for its high density and Z and relatively low melting point, is proposed as a beam dump material to safely dispose of this power. Achieving the necessary effective interaction thickness of 10 to 20 cm presents challenges in optimizing both mass flow rates and the geometric configuration of the lead. This study employs the Monte Carlo code FLUKA to simulate energy deposition and thermal simulations to investigate multiphase flow dynamics within an open-channel configuration. Various slope designs for a free-flowing liquid lead stream within an argon-filled vessel are explored to prevent oxidation. By optimizing the slope and shape of the lead flow, this work seeks to enhance energy absorption and thermal management, improving the effectiveness of liquid lead in high-power beam dump applications.

CERN’s upcoming SPS Beam Dump Facility (BDF) will host a production target designed to manage challenging thermal and mechanical conditions while providing the physics output required by the Search for Hidden Particles (SHiP) experiment. It must fully absorb 400 GeV/c protons and dissipate up to 305 kW. The baseline design consists of water-cooled tantalum-alloy clad TZM and tungsten (W) blocks. Challenges for the maintenance and reliability of the baseline design led to the development of alternative concepts. The leading design—a helium-cooled W target—optimizes thermal management and structural integrity while simplifying the manufacturing and improving its physics performance for the SHiP experiment. The experimental validation of this concept will be via testing multiple prototypes in an existing slow beam extraction test bench at CERN’s North Area. In parallel, extensive R&D is being pursued on: properties of pure W products including hot-rolled plates; manufacturing of seamless blocks; W-W diffusion bonding techniques. This contribution includes an overview of the helium-cooled target design and a summary of the ongoing material characterization, prototyping and beam-tests.

The CERN accelerator complex relies critically on fast injection and extraction processes to transfer particle beams between accelerators via fast pulsed magnets, or kickers. Ensuring high availability is paramount, as the reliability of these systems directly impacts the large number of experiments conducted at CERN. In this paper, we propose to explore Continual Learning (CL) methods, specifically using Variational Autoencoders (VAEs), to develop an anomaly detection system for the fast kicker magnets. By continuously learning from evolving data while retaining prior knowledge, these models will be capable of detecting anomalies without the need for repeated retraining. This approach is particularly relevant for ensuring the reliability and stability of kicker magnets, where early anomaly detection is critical for preventing performance degradation.

The Beam Interlock System is a key element of machine protection in CERN’s accelerators. It provides a fast and reliable way to link the accelerator systems to the beam dumping system, which ensures the safe extraction of the beams. This paper presents the reliability study of the new Beam Interlock System, which will replace the current system and will be deployed during CERN’s Long Shutdown 3. The upgrade features many improvements while maintaining the proven architecture of the previous system. In the study, each of the system’s boards were analysed through a detailed, component-level FMECA. This approach quantifies all operational risks, as well as identifies the most critical components. The risk on the system level is estimated using a global reliability model, which establishes functional dependencies between individual boards. It accounts for system-level redundancies, inspection and maintenance strategies. The results show that the stringent reliability requirements, set in the view of possible catastrophic damages to the equipment in case of malfunction, are met with safety margins. They also highlight the importance of appropriate maintenance, testing and monitoring.

The new Universal Quench Detection System (UQDS) and Protection Devices Supervision Unit (PDSU) are pivotal elements for the quench protection system of the new HL-LHC inner triplet superconducting magnets as well as for requesting a beam dump upon activation of the active quench protection systems, the novel Coupling Loss Induced Quench System (CLIQ) and the traditional quench heaters (HDSs). Given the criticality of these functionalities, a thorough reliability analysis has been carried out to ensure that the probability of critical failures meets the stringent reliability requirements under all operational conditions. To determine the failure probabilities, analytical models were developed that consider redundancies, inspection strategies and demand frequencies. The models’ failure parameters were identified by a component-based Failure Mode, Effects and Criticality Analysis (FMECA). The results of the models allow the qualification of the system design as well as insights on critical monitoring and testing requirements of the system when in operation.