Collider Rings and IR Design for MEIC

Transcription

1 Collider Rings and IR Design for MEIC Alex Bogacz for MEIC Collaboration Center for Advanced Studies of Accelerators EIC Collaboration Meeting The Catholic University of America Washington, DC, July 29-31, 21

2 Figure-8 Collider Rings x [cm] Figure-8 Collider Ring - Footprint z [cm] total ring circumference ~1 m 6 deg. crossing Collider Ring size is a compromise between synchrotron radiation and space charge 3-11 GeV electrons 2-6 GeV ions (with 6 Tesla dipoles) 1 GeV ions (with 8 Tesla dipoles)

3 Collider Rings with Relaxed IR Optics Larger Figure-8 Rings (~1 m circumference) 6 Tesla bends for ions at 6 GeV Additional straights to accommodate spin rotators and RF Horizontal IR crossing, dispersion free straights Relaxed IR Design: Chromaticity Compensating Optics max m Uncompensated dispersion in the straights Anti-symmetric dispersion pattern across the IR Dedicated Symmetric Inserts around the IR x y 1cm 2cm Electron Collider Ring based on emittance preserving Optics

4 PHASE_X&Y Ion Ring - 9 FODO Cell E = 6 GeV phase adv/cell: Df x,y = Q_X Q_Y Arc dipoles: $Lb=3 cm $B=58.2 kgauss $ang=5 deg. $rho = 34.4 meter Arc quadrupoles $Lq=65 cm $G= 1.5 kg/cm 9 offers intrinsic cell-to-cell cancellation of beta chromaticity off momentum beta wave propagates with twice the betatron frequency (18 after two cells - cancellation)

5 2 2 Quarter Arc Achromat 12 deg. Arc B/2 B/2 B/2 B/ dis. sup. cells 1 FODO cells 2 dis. sup. cells 28 3 meter dipoles

6 2 2 Ion Ring - Arc Optics 24 deg. Arc 26 quarter Arc 12 meter Straight 2 meter quarter Arc 12 meter

7 PHASE_X&Y Electron Ring FODO Cell E = 11 GeV phase adv/cell: Df x,y = Q_X Q_Y Arc dipoles: $Lb=11 cm $B=12.5 kgauss $ang=2.14 deg. $rho = 29.4 meter Arc quadrupoles $Lq=4 cm $G= 9 kg/cm 135 FODO offers emittance preserving optics H minimum Synchrotron radiation power per meter less than 2 kw/m

8 15.15 Quarter Arc Achromat 12 deg. Arc 12 2 dis. sup. cells 26 FODO cells 2 dis. sup. cells 2B/3 B/3 2B/3 B/ meter dipoles

9 15.15 Electron Ring - Arc Optics 24 deg. Arc 26 quarter Arc 12 meter Straight 2 meter quarter Arc 12 meter

10 Flexible Momentum Compaction Cell E = 11 GeV 135 FODO Theoretical Emittance Minimum FMC Cell H minimum e x e x 2

11 EM Calorimeter HTCC RICH EM Calorimeter Hadron Calorimeter Muon Detector Detector and IR layout low-q 2 electron detection dipole large aperture electron quads central detector with endcaps small angle hadron detection dipole ion quads ultra forward hadron detection dipole small diameter electron quads ~5 mrad crossing Solenoid yoke + Muon Detector Solenoid yoke + Hadronic Calorimeter RICH Tracking 5 m solenoid Pawel Nadel-Turonski

12 8 5 IR Optics (electrons) () 2 ff m IR f 2 1 f f x y 1cm 2cm max g FF f Natural Chromaticity: x = -47 y = FF doublets l = 3.5m

13 Size_X[cm] Size_Y[cm] IR Optics (electrons at 5 GeV) e e x N y N m m x y 1cm 2cm e g () N 19 Ax_bet Ay_bet Ax_disp Ay_disp 19 Q4 Q3 Q2 Q1 Q1 G[kG/cm] = -2.8 Q2 G[kG/cm] = 3.1 Q3 G[kG/cm] = -2. Q4 G[kG/cm] = x 31-6 y m m

14 Synchrotron Radiation Background x W 5 mm P + 4.6x mm 5 mrad Photons incident on various surfaces from the last 4 quads FF1 24 FF2 3 mm e Rate per bunch incident on the surface > 1 kev Beam current = 2.32 A 2.9x1 1 particles/bunch Rate per bunch incident on the detector beam pipe assuming 1% reflection coefficient and solid angle acceptance of 4.4 % M. Sullivan July 2, 21 F$JLAB_E_3_5M_1A Michael Sullivan, SLAC

15 3 5 IR Optics (ions) () 2 ff m IR f 2 1 f f x y 1cm 2cm max g FF f Natural Chromaticity: x = -88 y = FF triplet : Q3 Q2 Q1 l = 7m

16 Size_X[cm] Size_Y[cm] IR Optics (ions) at 6 GeV e e x N y N m m x y 1cm 2cm e g () N 5 Ax_bet Ay_bet Ax_disp Ay_disp 5 FF triplet : Q3 Q2 Q1 Q1 G[kG/cm] = -9.7 Q2 G[kG/cm] = 6.9 Q3 G[kG/cm] = x 31-6 y m m

17 IR Chromaticity Compensation ions Df x 2 Df y Arc end Df x p Df x,y p Df x,y p Chromaticity Compensation with four families of sextupoles

18 Chromaticity Compensation electrons Df x 2 Df y Df x,y p Df x,y p Df x p Chromaticity Compensation with four families of sextupoles

19 31 32 Collider Ring Tune Diagram Working point above half integer a la KEKB: Q x =36.56 Q y =

20 Tune Chromaticity Correction Large momentum acceptance and dynamic aperture Dp p -3 Hisham Sayed, Old Dominion Univ.

21 Arc - Spin Rotator - IR electrons Arc 8 m drift space for low Q 2 tagging IR Chromaticity Compensation Block Spin Rotator

22 Electron and Ion IRs - Overlay ions electrons Chromaticity Compensation Block electrons Spin rotator

23 Summary Complete design of Figure-8 Collider Rings (~ 1 m circumference) Emittance preserving Arcs based on 135 FODO lattice (11 GeV electrons) Periodic dispersion Arcs based on 9 FODO lattice (6 GeV ions) Relaxed IR Design: max m xy, 1 / 2cm Chromatic compensation with sextupoles IR chromaticity Dispersive Straights - disp. leakage from the Arcs (by design) Anti-symmetric dispersion pattern across the IR Dedicated Optics Symmetric inserts Beta Chromaticity compensation (immediate vicinity of the ) Dp Large Momentum Acceptance open, DA tracking p -3