Status of the positron beamline at MAMI

• Pascal Klag (University of Mainz)

The Institute for Nuclear Physics of the University of Mainz operates the accelerator complex MAMI which supplies an electron beam with a maximum energy of 1.6 GeV and a beam current of up to 100 μA. Outstanding qualities of MAMI is the continuous beam with an excellent beam quality of 4 pi nm rad emittance, a very low energy spread of less than 10-4, as well as its extremely high reliability. All kind of channeling experiments require such a high quality beam with a low divergence. Positrons, however, are more preferable because they have a significant longer de-channeling length. The aim of a new project is the preparation of high-quality positron beam using the MAMI accelerator. The current beamline comprises a thin conversion target, a positron spectrometer for energy selection (530 MeV) and detector systems. The very low emittance of the positron beam, allows proper focusing via a pair of quadrupoles to a low divergence. A parallel positron has been demanded by theory for future channeling radiation experiments. Preliminary tests of the positron beamline have been performed and will be presented within the talk.

Overview and the current status of the FCC-ee positron source

• Fahad Alharthi (Université Paris-Saclay - CNRS/IN2P3/IJCLab)

The Future Circular Collider (FCC-ee), currently in the Feasibility Study phase, is an electron-positron collider designed for various operational modes, including Z, W, H bosons, and ttbar. To achieve high luminosity, it requires a high-intensity, low-emittance positron source. This presentation will provide a brief overview of the FCC-ee injector complex and focus on the positron source. It will cover ongoing studies on two positron production schemes: conventional and crystal-based, emphasising their performances. Finally, will conclude with a description of the developed simulation models and experimental studies, including an overview of the proof-of-principle positron source experiment at PSI (P3) aimed at validating the proposed positron source design.