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The European Spallation Source (ESS), currently under construction in Lund, Sweden, will be the world’s brightest neutron source, driven by a linear accelerator (LINAC) with an average beam power of 5 MW at 2.0 GeV beam energy. The LINAC accelerates a proton beam of 62.5 mA peak current at 4% duty cycle (2.86 ms at 14 Hz). The accelerator uses a normal conducting front-end bringing the beam energy to 90 MeV, beyond that the acceleration up to 2 GeV is performed using superconducting structures. The first protons were extracted at the ESS site during the commissioning of the ion source and low energy beam transport that started earlier this year and will continue to the next stage of the commissioning up to 21 MeV early next year. This paper gives an overview of the status of the ESS accelerator and the commissioning of the ion source and the low energy beam transport.

International audience; Saclay CEA/IRFU is working for the delivery of five Non-Invasive Profile Monitors in the frame of the in-kind contribution agreement signed with the European Spallation Source. Neutrons will be produced by spallation reactions of 2 GeV proton beam impinging on a Tungsten target. To accelerate protons a powerful linear accelerator of 5MW is under construction. Diagnostic devices are mandatory tools for the tuning and protection of the machine. The non-invasive profile monitors provide a measurement of the beam profile in transverse directions to the beam propagation. This project raises several physical and technical challenges including low signal detection of ions or electrons, profile distortions induced by the beam Space Charge effect and non-uniformities of electric field. Simulation and model of the critical aspects of the detector have been performed in order to prove the performance and the feasibility of the detector. A series of prototypes has been built with different readout types, and tested in real conditions at the 3MeV proton accelerator IPHI. All of them show some advantages and drawbacks revealed by the tests in real beam conditions. In this paper we present the results of the tests for the various configuration readout systems to agree with the model and simulation of the detector. In concluding remarks, we will discuss the performance of the prototypes and point out the camerabased one to be the more suitable for the final design.Key words: Beam diagnostic / Linear proton accelerators / MCP / Strip detector / Particle beam measurements

The proton linac of the European Spallation Source, under construction in Lund, Sweden, had beam commissioning of its ion source (IS) and the following low energy beam transport (LEBT) at their final locations from September 2018 to July 2019. This was first of several beam commissioning stages for the linac of ESS, towards the start of the user program in 2023. This paper presents highlights of characterizations of the IS and LEBT from the aforementioned beam commissioning period, including behavioral change of the IS against its parameters, error source identifications of the beam trajectory in the LEBT, and preliminary characterization of the LEBT output beam against solenoid strengths in LEBT.

This paper presents a brief summary of the contributions to Working Group 5 (WG5): Beam Sources, Monitoring, and Control. This working group was part of the 2018 Advanced Accelerator Concepts Workshop held at Breckenridge, Colorado, from August 12–17, 2018. There was wide-range of topics covered by this working group ranging from facility updates, new diagnostics and instrumentation schemes, new characterization methods and demonstrations (for both plasma and beam) as well as several advanced concepts that fall outside the scope of the other working groups.

Physical review / X 8(2), 021039 (2018). doi:10.1103/PhysRevX.8.021039, Similarly to laser or x-ray beams, the interaction of sufficiently intense particle beams with neutral gases will result in the creation of plasma. In contrast to photon-based ionization, the strong unipolar field of a particle beam can generate a plasma where the electron population receives a large initial momentum kick and escapes, leaving behind unshielded ions. Measuring the properties of the ensuing Coulomb exploding ions—such as their kinetic energy distribution, yield, and spatial distribution—can provide information about the peak electric fields that are achieved in the electron beams. Particle-in-cell simulations and analytical models are presented for high-brightness electron beams of a few femtoseconds or even hundreds of attoseconds, and transverse beam sizes on the micron scale, as generated by today’s free electron lasers. Different density regimes for the utilization as a potential diagnostics are explored, and the fundamental differences in plasma dynamical behavior for e-beam or photon-based ionization are highlighted. By measuring the dynamics of field-induced ions for different gas and beam densities, a lower bound on the beam charge density can be obtained in a single shot and in a noninvasive way. The exponential dependency of the ionization yield on the beam properties can provide unprecedented spatial and temporal resolution, at the submicrometer and subfemtosecond scales, respectively, offering a practical and powerful approach to characterizing beams from accelerators at the frontiers of performance., Published by APS, College Park, Md.

The AWAKE Collaboration has been formed in order to demonstrate proton-driven plasma wakefield acceleration for the first time. This acceleration technique could lead to future colliders of high energy but of a much reduced length when compared to proposed linear accelerators. The CERN SPS proton beam in the CNGS facility will be injected into a 10 m plasma cell where the long proton bunches will be modulated into significantly shorter micro bunches. These micro-bunches will then initiate a strong wakefield in the plasma with peak fields above 1 GV/m that will be harnessed to accelerate a bunch of electrons from about 20 MeV to the GeV scale within a few meters. The experimental program is based on detailed numerical simulations of beam and plasma interactions. The main accelerator components, the experimental area and infrastructure required as well as the plasma cell and the diagnostic equipment are discussed in detail. First protons to the experiment are expected at the end of 2016 and this will be followed by an initial three-four years experimental program. The experiment will inform future larger-scale tests of proton-driven plasma wakefield acceleration and applications to high energy colliders. info:eu-repo/semantics/publishedVersion