Limited dynamic aperture which is in the consequence of strong nonlinearities in a low emittance storage ring, is a challenging issue from beam dynamics point of view. In the present study, we have applied three families of focusing and defocusing octupoles to the storage ring lattice with the aim of increasing dynamic aperture and beam lifetime . We have discussed different methods to optimize of the position and strength of octupoles so that each octupole family fights a specific resonance driving term.

FCC-ee is a proposed lepton collider with a circumference close to 100 km to produce an unprecedented amount of luminosity. The FCC-ee optics tuning working group is addressing one of the most critical aspects of the FCC-ee, that is the recovery of the optics design performance in presence of realistic imperfections. Various teams from laboratories all around the world have got together to assess field quality tolerances and review and share experience gained at synchrotron light sources and lepton colliders such as SuperKEKB. This paper reports the latest results on optics measurements and tuning simulations for various techniques, the development of simulation tools, and possible layout design changes to optimize the tuning performance.

Limited dynamic aperture which is in the consequence of strong nonlinearities in a low emittance storage ring, is a challenging issue from beam dynamics point of view. In the present study, we have applied three families of focusing and defocusing octupoles to the storage ring lattice with the aim of increasing dynamic aperture and beam lifetime . We have discussed different methods to optimize of the position and strength of octupoles so that each octupole family fights a specific resonance driving term.

The resistive contribution of the vacuum chamber is a significant part of the impedance budget. Due to the NEG-coated re-designed ILSF vacuum chamber, the resistive-wall effects must be carefully studied. The resistive impedance of the insertion devices and general cross-section of the storage ring was calculated by CST and WI2D code. In addition, the fast-correctors containing a resistive insert with a conductivity different from the rest of the pipe were simulated in CST. Finally, the not negligible effect of the heat load and threshold current was studied. The single-bunch calculations were done by ELEGANT code. The final results in longitudinal and transverse planes are presented here.

The standard injection scheme of ILSF is composed of 2 septum and 4 kicker magnets installed in a 7-meter-long straight section. Further tuning of the 4 kicker devices to reduce perturbations has proven to be almost impossible since it requires having 4 identical magnets, electronics, and Ti-coated ceramic chambers. Different from pulsed dipole kicker magnets used in a conventional local-bump injection, the single nonlinear or multipole kicker provides a nonlinear distribution of magnetic fields, which has a maximum value off the axis where the injected beam arrives and a zero or near-zero value at the center where the stored beam passes by. So, here the designs of different multipole kickers, including sextupole, octupole, and a nonlinear kicker, have been investigated and compared.