Design of a fast chromaticity jump in RHIC

During transition crossing in the Relativistic Heavy Ion Collider (RHIC), chromaticities have to change sign. This sign change is partially accomplished by the γ_t quadrupole jump; however, the resulting chromaticity jump is only Δξ_x = 2.1 in the horizontal and Δξ_y = 2.4 in the vertical plane. To increase the jump height, a dedicated chromaticity jump scheme has been designed, consisting of fast power supplies connected to six sextupoles per ring, which is capable of providing a chromaticity jump of Δξ = 6.