Layout and performance of the FCC-ee pre-injector chain

S Ogur,L Rinolfi,S M Polozov,K Oide,T Kamitani,A Barnyakov,D Nikiforov,R Chehab,A Levichev,E V Ozcan,F Miyahara,P Martyshkin,K Furukawa,T Charles,Y Papaphilippou,N Iida,F Zimmermann,I Chaikovska

doi:10.1088/1742-6596/1067/2/022011

Abstract

The Future Circular e+e− Collider pre-injector chain consists of a 6 GeV S-Band linac, a damping ring at 1.54 GeV and pre-booster ring to reach 20 GeV for injection to the main booster. The electron and positron beams use the same accelerator chain alternatively. The e−beam is generated from a novel low level RF-gun providing 6.5 nC charge at 11 MeV with 0.5 micron geometric emittance. The e+ beam is produced by the impact of a 4.46 GeV e− beam onto a hybrid target, accelerated in the linac up to 1.54 GeV, and injected to the damping ring for emittance cooling. Simulations on the performance of the DR are presented for reaching the required equilibrium emittances at the required damping time. As an alternative option, a 20 GeV linac is considered utilising C-Band cavities and simulations studies have been undertaken regarding the beam transport and transmission efficiency up to that energy.

Highlights

The Future Circular Collider’s luminosity frontier the FCC-ee will require very high charge flux and a very fast topup injection to keep the luminosity around 2 × 1036 cm−2s−1 throughout the operation at the resonance energy of the Z boson
Concerning the longitudinal wakefields in the linac, the bunch to bunch spacing is chosen as 60 ns [14]. 2 bunches per RF pulse in the linac will become a train in the DR
This e+ beam has been injected into the DR, where its optics shown in Fig. 4, for a store time of 45 ms, which stems from the interleaved injection/extraction of the 5 trains

Summary

INTRODUCTION

The Future Circular Collider’s luminosity frontier the FCC-ee will require very high charge flux and a very fast topup injection to keep the luminosity around 2 × 1036 cm−2s−1 throughout the operation at the resonance energy of the Z boson. There will be 4 operational modes of the FCC-ee, namely Z, W , H, and ttoperations. The Z mode is the main focus of the pre-injectors since it requires the highest charge with the lowest equilibrium emittance compared to the other 3 modes. Once the Zoperation requirements are satisfied, the other parameters for the other collider flavors will be within the reach.

45.6 GeV 16640

Result

1.54 GeV DAMPING RING

Findings

CONCLUSIONS