Design of beam optics for the future circular collider $e^{+}{e}^{-}$ collider rings

Journal Article · Mon Nov 21 00:00:00 EST 2016 · Physical Review Accelerators and Beams

DOI:https://doi.org/10.1103/PhysRevAccelBeams.19.111005· OSTI ID:1339646

Oide, Katsunobu ^[1]; Aiba, M. ^[2]; Aumon, S. ^[2]; Benedikt, M. ^[2]; Blondel, A. ^[3]; Bogomyagkov, A. ^[4]; Boscolo, M. ^[5]; Burkhardt, H. ^[2]; Cai, Y. ^[6]; Doblhammer, A. ^[2]; Haerer, B. ^[2]; Holzer, B. ^[2]; Jowett, J. M. ^[2]; Koop, I. ^[4]; Koratzinos, M. ^[3]; Levichev, E. ^[4]; Medina, L. ^[2]; Ohmi, K. ^[1]; Papaphilippou, Y. ^[2]; Piminov, P. ^[4] ; Shatilov, D. ^[4]; Sinyatkin, S. ^[6]; Sullivan, M. ^[6]; Wenninger, J. ^[2]; Wienands, U. ^[7]; Zhou, D. ^[1]; Zimmermann, F. ^[2]

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1. The High Energy Accelerator Research Organization (KEK), Tsukuba (Japan)
2. Paul Scherrer Inst. (PSI), Villigen (Switzerland)
3. Univ. of Geneva (Switzerland). Dept. of Nuclear and Particle Physics (DPNC)
4. Russian Academy of Sciences (RAS), Novosibirsk (Russian Federation). Budker Inst. of Nuclear Physics (BINP)
5. National Inst. for Nuclear Physics (INFN), Frascati (Italy). National Lab. of Frascati (LNF)
6. SLAC National Accelerator Lab., Menlo Park, CA (United States)
7. Argonne National Lab. (ANL), Argonne, IL (United States)

A beam optics scheme has been designed for the future circular collider-e⁺e^– (FCC-ee). The main characteristics of the design are: beam energy 45 to 175 GeV, 100 km circumference with two interaction points (IPs) per ring, horizontal crossing angle of 30 mrad at the IP and the crab-waist scheme with local chromaticity correction. The crab-waist scheme is implemented within the local chromaticity correction system without additional sextupoles, by reducing the strength of one of the two sextupoles for vertical chromatic correction at each side of the IP. So-called “tapering” of the magnets is applied, which scales all fields of the magnets according to the local beam energy to compensate for the effect of synchrotron radiation (SR) loss along the ring. An asymmetric layout near the interaction region reduces the critical energy of SR photons on the incoming side of the IP to values below 100 keV, while matching the geometry to the beam line of the FCC proton collider (FCC-hh) as closely as possible. Sufficient transverse/longitudinal dynamic aperture (DA) has been obtained, including major dynamical effects, to assure an adequate beam lifetime in the presence of beamstrahlung and top-up injection. In particular, a momentum acceptance larger than ±2% has been obtained, which is better than the momentum acceptance of typical collider rings by about a factor of 2. The effects of the detector solenoids including their compensation elements are taken into account as well as synchrotron radiation in all magnets. The optics presented in this paper is a step toward a full conceptual design for the collider. Lastly, a number of issues have been identified for further study.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Argonne National Laboratory (ANL), Argonne, IL (United States); Paul Scherrer Inst. (PSI), Villigen (Switzerland); Russian Academy of Sciences (RAS), Novosibirsk (Russian Federation)
• Sponsoring Organization: USDOE; European Commission (EC); National Council of Science and Technology (CONACyT) (Mexico)
• Contributing Organization: The High Energy Accelerator Research Organization (KEK), Tsukuba (Japan); Univ. of Geneva (Switzerland); National Inst. for Nuclear Physics (INFN), Frascati (Italy)
• Grant/Contract Number: AC02-76SF00515; 312453
• OSTI ID: 1339646
• Alternate ID(s): OSTI ID: 1349099
• Journal Information: Physical Review Accelerators and Beams, Vol. 19, Issue 11; ISSN 2469-9888
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

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