Full-Acceptance Detector Integration at MEIC

Vasiliy Morozov for MEIC Study Group

Electron Ion Collider Users Meeting, Stony Brook University

June 27, 2014

EIC Users Meeting 6/27/14 2

Lattice design of geometrically-matched collider rings completedDetector locations minimize synchrotron and hadronic backgrounds

. Close to arc where ions exit. Far from arc where electron exit

Collider Rings

IPs

e-

ions

e-

ions

IP

EIC Users Meeting 6/27/14 3

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-Q2 tagger. Small-angle electron detection

Full-Acceptance Detector

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

EIC Users Meeting 6/27/14 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

IP

ions

matching section\coupling comp. FFB FFB

detectorelements CCB\

geom. match\disp. suppression

matching section\coupling comp.

matchingsection

EIC Users Meeting 6/27/14 5

Detector Modeling & Machine IntegrationFully-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

far forwardfar forwardhadron detectionhadron detectionlow-Q2

electron detectionelectron detection large-apertureelectron quads

small-diameterelectron quads

central detectorcentral detector with endcaps

ion quads

50 mrad beam(crab) crossing angle

n,

ep

p

small anglesmall anglehadron detectionhadron detection

~60 mrad bend

(from GEANT4)

2 Tm 2 Tm dipoledipole

EndcapEndcap Ion quadrupolesIon quadrupoles

Electron quadrupolesElectron quadrupoles

1 m1 m11 m m

IP FP

Roman potsRoman potsThin exit Thin exit windowswindows

Fixed Fixed trackerstrackers

Trackers and “donut” calorimeterTrackers and “donut” calorimeter

RICH+

TORCH?

dual-solenoid in common cryostat4 m coil

barrel DIRC + TOF

EM

ca

lori

met

er

EM calorimeter

Tracking

EM

ca

lori

met

er

e/π

th

res

ho

ldC

he

ren

ko

v

EIC Users Meeting 6/27/14 6

Far-Forward AcceptanceTransmission 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

elec

tron

bea

m

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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

elec

tron

bea

m

±10 @ 60 GeV/c

|p/p| > 0.005 @ x,y = 0

EIC Users Meeting 6/27/14 8

Far-Forward AcceptanceGEMC simulation framework developed by M. UngaroMILOU DVCS event generatorDetection 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:

Z.W. Zhao

/ / / '/ ' / /24 / 5 μm, / 0.24 mradx y x y x y x y x y x y

EIC Users Meeting 6/27/14 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

IP

electrons

matching section

FFB

FFB

detectorelements

disp. suppressionmatching section\coupling comp.CCB matching section\

coupling comp.

EIC Users Meeting 6/27/14 10

Small-Angle Electron DetectionLow-Q2 tagger

– Dipole chicane for high-resolution detection of low-Q2 electrons

low-Q2 tagger

final focusing elements

e-

ions

e-

ions

Electron beam aligned with solenoid axis

x e-

(top view)

EIC Users Meeting 6/27/14 11

Compton polarimeter in low-Q2 chicaneSame polarization as at the IP due to zero net bendNon-invasive continuous polarization monitoringPolarization measurement accuracy of ~1% expectedNo interference with quasi real photon tagging detectors

Electron Polarimetry

c

Laser + Fabry Perot cavity

e- beam

Quasi-real high-energy photon tagger

Quasi-real low-energy photon tagger

Electrontracking detector

Photon calorimeter

A. Camsonne, D. Gaskell

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Crab CrossingRestores 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

IPe-

ions

global/localcrab cavities

local crab cavities

EIC Users Meeting 6/27/14 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