Full-Acceptance Detector Integration at MEIC

Vasiliy Morozov for MEIC Study Group

Electron Ion Collider Users Meeting, Stony Brook University June 27, 2014

Collider Rings

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 IPs IP ions e ions e EIC Users Meeting 6/27/14 2

Full-Acceptance Detector

50 mrad crossing angle Improved detection, no parasitic collisions, fast beam separation Forward hadron detection in three stages Endcap Small dipole covering angles up to a few degrees Far forward, up to one degree, for particles passing through accelerator quads Low-Q 2 tagger Small-angle electron detection EIC Users Meeting 6/27/14 3

R. Ent, C.E. Hyde, P. Nadel-Turonski

Ion IR Optics

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 matching section matching section\ coupling comp. FFB IP FFB detector elements CCB\ geom. match\ disp. suppression matching section\ coupling comp.

ions EIC Users Meeting 6/27/14 4

Detector Modeling & Machine Integration

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 low-Q 2 electron detection

p

(from GEANT4) large-aperture electron quads 50 mrad beam (crab) crossing angle central detector with endcaps small angle hadron detection ion quads small-diameter electron quads IP ~60 mrad bend Thin exit windows far forward hadron detection Fixed trackers FP

n,

g

p e

Roman pots

dual-solenoid in common cryostat 4 m coil RICH barrel DIRC + TOF + TORCH?

Tracking EM calorimeter

Endcap 1 m 1 m Ion quadrupoles 2 Tm dipole Electron quadrupoles Trackers and “donut” calorimeter EIC Users Meeting 6/27/14 5

Far-Forward Acceptance

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) 6 T max 9 T max 12 T max EIC Users Meeting 6/27/14 6

Momentum & Angular Resolution

– 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

±

10



@ 60 GeV/c

EIC Users Meeting 6/27/14 7

Far-Forward Acceptance

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:      24 / 5 μm,    /   0.24 mrad EIC Users Meeting 6/27/14 8

Z.W. Zhao

Electron IR Optics

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 CCB matching section FFB matching section\ coupling comp.

FFB detector elements disp. suppression matching section\ coupling comp.

electrons IP EIC Users Meeting 6/27/14 9

Small-Angle Electron Detection

Low-Q 2 tagger – Dipole chicane for high-resolution detection of low-Q 2 electrons x e e (top view) ions low-

Q 2

tagger Electron beam aligned with solenoid axis e final focusing elements EIC Users Meeting 6/27/14 10

Electron Polarimetry

Compton polarimeter in low-Q 2 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

Laser + Fabry Perot cavity Photon calorimeter

 c

Quasi-real low-energy photon tagger Quasi-real high-energy photon tagger Electron tracking detector e beam

EIC Users Meeting 6/27/14 11

A. Camsonne, D. Gaskell

Crab Crossing

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 local crab cavities ions IP global/local crab cavities e EIC Users Meeting 6/27/14 12

Summary & Outlook

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  M. Sullivan  SLAC Z.W. Zhao  Old Dominion University JLab & Old Dominion University EIC Users Meeting 6/27/14 13