Ion Collider Ring Using Superferric Magnets V. Morozov, A. Hutton, F. Lin, F. Pilat, Y. Zhang MEIC R&D Meeting, JLab, August 21, 2014 F. Lin

Boundary Conditions Reusing of PEP-II hardware as much as possible ~2500 m ring circumference Superferric magnets for the ion collider ring Maximum field of about 2 T Supposed to be cheap Run at 4 K Quickly rampable at a few T/s Ring components included so far Dipoles: 0.14 m edge + 6.5 m magnetic length + 0.14 m edge, 2 T maximum field Quadrupoles: 0.05 m edge + 0.8 m magnetic length + 0.05 m edge, <=2 T @ 3 cm radius = 67 T/m Sextupole/corrector package: 0.05 m edge + 0.5 m magnetic length + 0.05 m edge, <=2 T @ 3 cm radius = 4400 T/m2, next to each quadrupole BPMs: 0.15 m, next to each quadrupole Spacings 0.15 m and 0.6 m between the element physical edges in the arcs One ion FODO cell per one electron TME-type cell Maximum proton momentum of 79.4 GeV/c 2

FODO Cell Aperture radius 30 mm Dipoles Quadrupoles Magnetic/physical length 6.5/6.78 m Bending angle 49.1 mrad (2.8), bending radius 132.4 m 2 T @ 79.4 GeV/c Quadrupoles Magnetic/physical length 0.8/0.9 m 52.4 and -52.5 T/m field gradients @ 79.4 GeV/c for 90 x/y betatron phase advance 1.57 and -1.58 T @ 30 mm radius Sextupole/corrector package next to each quadrupole Magnetic/physical length 0.5/0.6 m 2 T @ 30 mm focusing sextupole adds 22.0/-4.7 x/y units of chromaticity 2 T @ 30 mm defocusing sextupole adds -2.5/11.6 x/y units of chromaticity BPM next to each quadrupole Physical length 0.15 m Drifts 0.6 m and 0.15 m Complete FODO Length 18.36 m Arc radius 187.0 m 3

Dispersion Suppressor Quadrupoles 52.9, -52.4, 63.3, and -44.5 T/m field gradients @ 79.4 GeV/c 1.59, -1.57, 1.90 and -1.33 T @ 30 mm radius 4

Straight FODO Quadrupoles 54.2 and -54.2 T/m field gradients @ 79.4 GeV/c for 90 x/y betatron phase advance 1.63 and -1.63 T @ 30 mm radius 5

Matching Section Quadrupoles 52.1, -52.8, 43.8, and -63.0 T/m field gradients @ 79.4 GeV/c 1.56, -1.58, 1.31 and -1.89 T @ 30 mm radius 6

Complete Ring Circumference: 2510.6 m 90 crossing angle of figure 8 Each arc: 270 with radius of 187 m, 879.18 m long 44 FODO cells per arc + 4 FODO cells per arc used for dispersion suppression Each straight: 376.1 m long 17 FODO cells per straight + 4 FODO cells per straight used for matching tr = 17.96 7

Layout 8