DAΦNE is a a medium energy electron-positron collider operating in the National Laboratory of INFN at Frascati, Italy. The accelerator complex consists of two rings with an approximate circumference of 97 m. High-intensity electron and positron beams circulate and collide with the center of mass energy of around 1.02 GeV. The FCCee is an ongoing lepton collider project and its current injector design includes a damping ring for emittance cooling of positron beams. The electron cloud is one the most important collective effects and can represent a bottleneck for the performances of accelerators storing particles with positive charge. Several undesired effects such as transverse instabilities, beam losses, emittance growth, energy deposition, vacuum degradation may arise due to interaction of the circulating beam with the e-cloud. The aim of this presentation is to provide e-cloud buildup simulations for the DAΦNE positron ring and the Damping Ring of FCCee. This study will also include experimental studies concerning the instabilities induced by the e-cloud exploiting the opportunity offered by the positron beam at DAΦNE.

DAΦNE is a a medium energy electron-positron collider operating in the National Laboratory of INFN at Frascati, Italy. The accelerator complex consists of two rings with an approximate circumference of 97 m. High-intensity electron and positron beams circulate and collide with the center of mass energy of around 1.02 GeV. The FCCee is an ongoing lepton collider project and its current injector design includes a damping ring for emittance cooling of positron beams. The electron cloud is one the most important collective effects and can represent a bottleneck for the performances of accelerators storing particles with positive charge. Several undesired effects such as transverse instabilities, beam losses, emittance growth, energy deposition, vacuum degradation may arise due to interaction of the circulating beam with the e-cloud. The aim of this presentation is to provide e-cloud buildup simulations for the DAΦNE positron ring and the Damping Ring of FCCee. This study will also include experimental studies concerning the instabilities induced by the e-cloud exploiting the opportunity offered by the positron beam at DAΦNE.

In autumn 2023, the FCC Feasibility Study underwent a crucial “mid-term review”. We describe some accelerator performance risks for the proposed future circular electron- positron collider, FCC-ee, identified for, and during, the mid-term review. For the collider rings, these are the collective effects when running on the Z resonance – especially resistive wall, beam-beam, and electron cloud –, the beam lifetime, dynamic aperture, alignment tolerances, and beam-based alignment. For the booster, the primary concern is the vacuum system, with regard to impedance and effects of the residual gas. For the injector, the layout and the linac repetition rate are primary considerations. We discuss the various issues and report the planned mitigations.

DAFNE, the Frascati F-factory the collider where the Crab-Waist collision scheme has been implemented and successfully tested, is presently working for a physics program in the field of exotic atoms. The present scientific program foresees the study and the characterization of the never observed before kaonic deuterium. Providing a suitable data sample for such measurement requires the collider to provide the highest flux of k- meson and the lowest possible background shower on the detector. The operation strategy, and the collider setup in terms of collisions and beam dynamics are presented and discussed.

The FCC-e+e- project foresees the realization of the most intense ever realized source of positrons providing a bunch charge of the order of 5 nC. This big number of positrons (≈3.12e+10) is produced by pair conversion following a 6 GeV electron beam bremsstrahlung on a target, and as a consequence has large divergence and energy spread. The actual design of the positron injector includes a damping ring and a bunch compressor to reduce the beam particle distributions in the longitudinal and transverse phase spaces to values appropriate for the injection in the common LINAC, which accelerates both electron and positron beams from 1.54 to 6 GeV. An energy compressor installed after the positron LINAC improves the positron acceptance in the damping ring. This contribution presents relevant aspects related to the damping of the positron beam including the evaluation of the damping ring transmission efficiency through the whole transfer line from the positron source to the common LINAC, the energy compressor, and the bunch compressor in the injection and extraction branches of the Damping Ring.