The studies and R&D on the high-intensity positron source for the FCC-ee have been initiated for a while. The positrons are produced by a 6 GeV electron drive-beam incident on a target-converter at 200 Hz. The drive beam comes in 2 bunches spaced by 25 ns with a maximum charge of ~5 nC per bunch. Two scenarios using conventional and hybrid targets are being studied for positron production. According to the FCC CDR, the Flux Concentrator is used as the matching device for the capture system, followed by several accelerating structures embedded in the solenoidal field. Then, the positrons are further accelerated to be injected into the damping ring. Recently, the feasibility study on using a SC solenoid for the positron capture has been started, and the design based on the HTS technology is under investigation. In addition, the large aperture 2 GHz RF structures, which have been specially designed for the FCC-ee positron capture system, are used with the goal of demonstrating accepted positron yield values well beyond the values obtained with state-of-the-art positron sources. The purpose of this paper is to review the current status of the FCC-ee positron source design, highlighting the recent research into the positron production, capture system, primary acceleration, and injection into the damping ring.

In view of the High-Luminosity (HL-LHC) upgrade of the LHC collimation system, different materials were investigated to determine how the jaws of the new collimators could be manufactured to meet the demanding requirements of HL-LHC, such as thermomechanical robustness and stability, RF impedance, UHV, etc. During the Long-Shutdown 2 (LS2), five primary and 10 secondary low-impedance collimators were already produced using novel material. For LS3, in addition to more secondary collimators, the production and installation of other types of collimators, including tertiaries and physics debris units, is planned. This paper details the final material choices and rationale for each collimator family.

In 2017, a proton-impact test HL-LHC collimator materials was carried out in the HiRadMat facility at CERN. The experiment, called “MultiMat”, enabled the testing of bulk and coated materials developed at CERN for different beam collimation functionalities. Manufacturing of these materials was then passed to the industry, leading to a series production for use in the collimators installed in the LHC during Long Shutdown 2 (LS2). The industrial versions of bulk and coating materials were tested in HiRadMat in 2021 in the “MultiMat-2” experiment, that efficiently re-used of the same experimental test bench as for “MultiMat”. This new experiment proved the reliability of the absorbers installed in LS2, and confirmed the possible use of alternative materials and coatings for the next LS3 collimator production. This paper describes the preparation and beam parameters of “MultiMat-2”, the experimental and data-acquisition equipment and the main results of the experiment.

The CERN ISOLDE facility is currently equipped with two uncooled iron blocks acting as beam dumps. In order to guarantee the reliability and safety of the installation for the years to come, a study has been launched to evaluate the possibility to exchange the ISOLDE beam dumps during LS3. The consolidation would also allow compatibility with the 2 GeV and intensity upgrade being discussed. The contribution will detail the challenges of the project and the path being proposed to tackle them.