Full-Acceptance Detector Integration at MEIC

1. Full-Acceptance Detector Integration at MEIC Vasiliy Morozov for MEIC Study Group Electron Ion Collider Users Meeting, Stony Brook University June 27, 2014

2. Lattice design of geometrically-matched collider rings completed Detector locations minimize synchrotron and hadronic backgrounds Close to arc where ions exit Far from arc where electron exit Collider Rings IPs IP ions e- ions e-

3. 50 mrad crossing angle Improved detection, no parasitic collisions, fast beam separation Forward hadron detection in three stages Endcap Small dipole covering anglesup to a few degrees Far forward, up to one degree,for particles passing through accelerator quads Low-Q2 tagger Small-angle electron detection Full-Acceptance Detector R. Ent, C.E. Hyde, P. Nadel-Turonski

4. IR design features Based on triplet Final Focusing Blocks (FFB) Asymmetric design to satisfy detector requirements and reduce chromaticity Spectrometer dipoles before and after downstream FFB, second focus downstream of IP No dispersion at IP, downstream dispersion suppression designed to function as CCB Ion IR Optics matching section detector elements matching section\ coupling comp. IP CCB\ geom. match\ disp. suppression matching section\ coupling comp. FFB FFB ions

5. Fully-integrated detector and interaction region satisfying Detector requirements: full acceptance and high resolution Beam dynamics requirements: consistent with non-linear dynamics requirements Geometric constraints: matched collider ring footprints small angle hadron detection IP FP (from GEANT4) far forward hadron detection n, g low-Q2 electron detection ion quads large-aperture electron quads ~60 mrad bend p small-diameter electron quads e 50 mrad beam (crab) crossing angle p Fixed trackers Thin exit windows Roman pots central detector with endcaps dual-solenoid in common cryostat 4 m coil 1 m Ion quadrupoles RICH + TORCH? 1 m Endcap barrel DIRC + TOF 2 Tm dipole Electron quadrupoles e/π threshold Cherenkov EM calorimeter Tracking EM calorimeter Trackers and “donut” calorimeter EM calorimeter Detector Modeling & Machine Integration

6. Transmission of particles with initial angular and p/p spread vs peak field Quad apertures = B max / (fixed field gradient @ 100 GeV/c) Uniform particle distribution of 0.7 in p/p and 1 in horizontal angle originating at IP Transmitted particles are indicated in blue (the box outlines acceptance of interest) 9 T max 6 T max 12 T max  electron beam Far-Forward Acceptance

7. Protons with p/p spread are launched at different angles to nominal trajectory Resulting deflection is observed at the second focal point Particles with large deflections can be detected closer to the dipole |p/p| > 0.005 @ x,y = 0  electron beam Momentum & Angular Resolution ±10 @ 60 GeV/c

8. GEMC simulation framework developed by M. Ungaro MILOU DVCS event generator Detection of recoil protons produced in DVCS process by forward detectors Acceptance limitation due to beam stay-clear rather than magnet apertures in this case Beam stay-clear depends the emittances achievable by beam cooling: Far-Forward Acceptance Z.W. Zhao

9. Design features similar to that of ion IR Triplet Final Focusing Blocks (FFB) Asymmetric design to satisfy detector requirements and reduce chromaticity Spectrometer dipole after downstream FFB, second focus downstream of IP No dispersion at IP, downstream dispersion suppression by chicane Electron IR Optics detector elements FFB matching section matching section\ coupling comp. disp. suppression CCB FFB matching section\ coupling comp. electrons IP

10. Low-Q2 tagger Dipole chicane for high-resolution detection of low-Q2 electrons e- x e- ions (top view) ions low-Q2 tagger Electron beam aligned with solenoid axis e- final focusing elements Small-Angle Electron Detection

11. Compton polarimeter in low-Q2 chicane Same polarization as at the IP due to zero net bend Non-invasive continuous polarization monitoring Polarization measurement accuracy of ~1% expected No interference with quasi real photon tagging detectors Electron Polarimetry Laser + Fabry Perot cavity Photon calorimeter c Quasi-real high-energy photon tagger Quasi-real low-energy photon tagger Electron tracking detector e- beam A. Camsonne, D. Gaskell

12. Restores effective head-on collisions with 50 crossing angle Luminosity preserved Two feasible technologies Deflective crabbing: transverse electric field of SRF cavities (developed at ODU) Dispersive crabbing: regular accelerating/bunching cavities in dispersive region Two possible schemes Global: one set of cavities upstream of IP next to FFB Local One set of cavities upstream of IP next to FFB Another set of cavities(n+1/2) downstream of IP Crab Crossing local crab cavities ions e- IP global/localcrab cavities

13. Lattice design of geometrically-matched collider rings developed Interaction regions integrated into collider rings Detector requirements fully satisfied Ongoing and future work Detector modeling Polarimetry development Design optimization Design of interaction region magnets Systematic investigation of non-linear dynamics Development of beam diagnostics and orbit correction scheme Acknowledgements P. Brindza, A. Camsonne, Ya.S. Derbenev, R. Ent, D. Gaskell, F. Lin,P. Nadel-Turonski, M. Ungaro, Y. Zhang  JLab C.E. Hyde, K. Park  Old Dominion University M. Sullivan  SLAC Z.W. Zhao  JLab & Old Dominion University Summary & Outlook