Update of SPPC Lattice and Compatibility Consideration with

Update of SPPC Lattice and Compatibility Consideration with CEPC Chen Yukai CEPC Working Day Meeting 2, March 2019

Outline • Present Lattice design of SPPC • Compatibility requirement • SPPC Lattice update • Summary

Present Lattice Design of SPPC Lattice of collimation • Length of each section at present: • 8 arcs, total length 83400 m • 2 IPs for pp, 1500 m each • 2 IRs for injection or RF, 1250 m each • 2 IRs for ep or AA, 1250 m each • 2 IRs for collimation( ee for CEPC ）, 4300 m each • C = 100 km

Requirements of Long Straight Section Lengths of SPPC and CEPC Layout Reasons of 4300 m LSS needed for SPPC Jianquan Yang Yiwei Wang Length of Long Straight section requirements IP 1 & IP 3 IP 2 & IP 4 STRs SPPC 4300 m 1500 m 1250 m CEPC 3320 m 3420 m 1192. 5 m Compatibility 4300 m 3420 m 1250 m

Additional Space Needed for Bypass requirement Additional space for bypass LSS_SPPC collimation 4. 3 km Add a short straight section 23 m LSS_CEPC ee increase to 4. 86 km CEPC ee collision region LSS_CEPC SCRF=3. 42 km CEPC SCRF region Bypass Scheme： • Add a short straight section at the end of ARC • Length of ARC moved can change the bypass distance • Lw is the additional space for bypass, which will be 280 m when the bypass distance is 23 m LSS_SPPC PP Bypass relationship Layout of the two ring Part of arc is moved to here Length of Long Straight section requirements IP 1 & IP 3 IP 2 & IP 4 STRs SPPC 4300 m 1500 m 1250 m CEPC 3320 m 3420 m 1192. 5 m Compatibility 4860 m 3420 m 1250 m

Lattice Update of SPPC Layout needed considering compatibility with CEPC Dipole L=213. 423 m SPPC L=14. 452 m B=11. 8 T ρ=10598. 8 m Equivalent radius of FODO cell : 13043. 3 m β_max= 361. 9 m, β_min= 62. 9 m D_max= 2. 36 m, D_min= 1. 136 m Phase of advance: 90 deg FODO cell update Dipole • Length of each section considering compatibility with CEPC: • 8 arcs, total length 78. 44 km • 2 IPs for pp, 3420 m each • 2 IRs for injection or RF, 1250 m each • 2 IRs for ep or AA, 1250 m each • 2 IRs for collimation( ee for CEPC ）, 4860 m each • C = 100 km L=209. 444 m SPPC L=14. 12 m B=12. 42 T ρ=10598. 8 m Equivalent radius of FODO cell : 12445 m β_max= 355. 1 m, β_min= 61. 7 m D_max= 2. 38 m, D_min= 1. 147 m Phase of advance: 90 deg CEPC Equivalent radius of FODO cell : 12812. 5 m Yiwei Wang

Layout needed considering compatibility with CEPC β(m) Lattice Update of SPPC Dispersion suppressor update： More compact, increase dipole filling factor • Length of each section considering compatibility with CEPC: • 8 arcs, total length 78. 44 km • 2 IPs for pp, 3420 m each • 2 IRs for injection or RF, 1250 m each • 2 IRs for ep or AA, 1250 m each • 2 IRs for collimation( ee for CEPC ）, 4860 m each • C = 100 km

Lattice Update of SPPC Co tio ec ns n io llis C o si er sp Di up ns ion r AR C AR Layout needed considering compatibility with CEPC sso e pr r ns so exte s re n pp ance ctio n u o i s v e t ec on ad n s s s ersi ase lisio s pa sp h ol By Di 2 π p C Update of p-p collision section • Length of each section considering compatibility with CEPC: • 8 arcs, total length 78. 44 km • 2 IPs for pp, 3420 m each • 2 IRs for injection or RF, 1250 m each • 2 IRs for ep or AA, 1250 m each • 2 IRs for collimation( ee for CEPC ）, 4860 m each • C = 100 km • • • Additional matching quadrupoles are needed, more independent power supplies! Bump of beta function and dispersion function! ( beta_max: 362 m -> 564 m; Dx_max: 2. 36 m -> 3. 37 m) Long straight section of SPPC collision increase from 1. 5 km to 3. 42 km, a 2 π phase advance extension section was designed.

Summary • Long straight section lengths are quite different between SPPC and CEPC, which should be decided first. • Equivalent radius of FODO cell should be compatibility between SPPC and CEPC • SPPC Bypass CEPC about 23 m • In collision section, a 2 π phase advance section extension was designed to fill the additional space.

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