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Description
A high-performance positron source is a crucial component of FCC-ee delivering the low-emittance, high-intensity beams. In particular, operation at the Z pole demands positron bunch charges of up to 5 nC at the Damping Ring (DR) injection. In the Feasibility Study Report, the positron source concept is based on a 2.86 GeV electron drive beam impinging on a 15 mm tungsten target. The capture section consists of a high-temperature superconducting (HTS) solenoid matching device, followed by a capture linac made of six 2 GHz travelling-wave accelerating structures embedded in a 0.5 T solenoidal channel.
In this work, we investigate a 3 GHz (S-band) RF option for the positron capture linac, taking advantage of the maturity and industrial availability of S-band technology. The study focuses on the impact of the higher RF frequency on positron capture efficiency, transverse and longitudinal beam characteristics and overall injection performance into the DR. Although the design effort is ongoing, this contribution presents the proposed 3 GHz capture layout, its main parameters and preliminary performance in comparison with the 2 GHz reference configuration.
| Paper status | Proceeding files received |
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