Main Design Parameters RHIC Magnets for MEIC Ion Collider Ring New MEIC Design Main Design Parameters RHIC Magnets for MEIC Ion Collider Ring Nov. 6, 2014

MEIC Design Goals Y. Zhang, IMP Seminar Energy (bridging the gap of 12 GeV CEBAF & HERA/LHeC) Full coverage of s from a few 100 to a few 1000 GeV2 Electrons 3-12 GeV, protons 20-100 GeV, ions 12-40 GeV/u Ion species Polarized light ions: p, d, 3He, and possibly Li, and polarized heavier ions Un-polarized light to heavy ions up to A above 200 (Au, Pb) Up to 2 detectors Luminosity Greater than 1033 cm-2s-1 per interaction point over a broad CM region Maximum luminosity should optimally be around √s=45 GeV Polarization At IP: longitudinal for both beams, transverse for ions only All polarizations >70% desirable Upgradeable to higher energies and luminosity 20 GeV electron, 250 GeV proton, and 100 GeV/u ion Y. Zhang, IMP Seminar

MEIC Parameters at 5x60 GeV Design Point Ring circumference m 1450 2200 Proton Electron Beam energy GeV 60 5 Collision frequency MHz 750 Current / particles per bunch A / 1010 0.5/0.416 3 / 2.5 0.37 / 0.31 Polarization % > 70 ~ 80 Energy spread 10-4 ~ 3 7.1 RMS bunch length mm 10 7.5 12 Horiz./ vert. emittance, norm. µm rad 0.35 / 0.07 54 / 11 68 / 13.6 Horizontal and vertical β* cm 10 / 2 (4 / 0.8) 12.7 / 2.53 (5 / 1) Vertical beam-beam tune shift 0.014 0.03 0.017 Laslett tune shift 0.06 Very small Distance from IP to 1st FF quad 7 (4.5) 3.5 Hour-glass effect 0.96 (0.84) 0.94 (0.79) Luminosity per IP, 1033 cm-2s-1 5.4 (11.7) 3.1 (6.5) Numbers in blue font are for a high luminosity detector Slide 3 3

RHIC+(new)High-Field Magnets for MEIC (2.2 km) Magnet type RHIC High field SC Maximum kinetic energy GeV 100 (186) 100 Dipole length m 9.45 2.1 Dipole maximum field T 3.4 (4.45) 2.15 6 Dipole bending radius / angle m / deg 139 / 3.9 155 / 3.5° 55.6 / 2.2° BDL split 100% 62% 38% Figure-8 crossing angle deg 100° 81.7° FODO cells / dipoles in each arc 72 / 36 23 / 46 FODO cell length / packing factor 29.6 / 0.638 31.6 / 0.73 Arc length / radius m / m 1065 / 218 731 / 160 Straight length 366 371 Ring circumference 2860 2205 RHIC magnet 9.45 m, up to 2.15 T High field magnet 2.1 m, up to 6 T

RHIC+(new) RHIC-Like Magnets for MEIC (2.2 km) Magnet type RHIC RHIC-like Maximum kinetic energy GeV 100 (186) 100 Dipole length m 9.45 4.2 Dipole maximum field T 3.4 (4.45) 2.15 4.45 Dipole bending radius / angle m / deg 139 / 3.9 155 / 3.5° 75 / 3.2° BDL split 100% 52% 48% Figure-8 crossing angle deg 100° 81.7° FODO cells / dipoles in each arc 72 / 36 19.5 / 39 FODO cell length / packing factor 29.6 / 0.638 37.4 / 0.73 Arc length / radius m / m 1065 / 218 729 / 160 Straight length 366 370 Ring circumference 2860 2199 RHIC magnet 9.45 m, up to 2.15 T New RHIC-like magnet 4.2 m, up to 4.45

RHIC+(new) RHIC-Like Magnets: Upgrade to 250 GeV Magnet type RHIC RHIC-like High-fld Maximum kinetic energy GeV 100 250 Dipole length m 9.45 4.2 Dipole maximum field T 2.15 4.45 8.3 Dipole bending radius / angle m / deg 155 / 3.5° 75 / 3.2° 100 / 5.4° 187 / 1.3° BDL split 52% 48% 81% 19% Figure-8 crossing angle deg 81.7° FODO cells / dipoles in each arc 19.5 / 39 FODO cell length / packing factor 37.4 / 0.73 Arc length / radius m / m 729 / 160 Straight length 370 Ring circumference 2199 RHIC magnet 9.45 m, up to 2.15 T New RHIC-like magnet 4.2 m, up to 4.45 T Replacing all RHIC magnets by 8.3 T high field SC magnets

RHIC+(new) RHIC-Like Magnets: Upgrade to 250 GeV Magnet type RHIC RHIC-like High-fld Maximum kinetic energy GeV 100 250 Dipole length m 9.45 4.2 Dipole maximum field T 2.15 4.45 12.1 Dipole bending radius / angle m / deg 155 / 3.5° 75 / 3.2° 187 / 2.9° 69 / 7.9° 187 / 1.3° BDL split 52% 48% 22% 59% 19% Figure-8 crossing angle deg 81.7° FODO cells / dipoles in each arc 19.5 / 39 19.5 / 19.5 FODO cell length / packing factor 37.4 / 0.73 Arc length / radius m / m 729 / 160 Straight length 370 Ring circumference 2199 Replacing only half RHIC magnets (one of two in a cell) by 12 T high field SC magnets RHIC magnet 9.45 m, up to 2.15 T New RHIC-like magnet 4.2 m, up to 4.45 T