1. Full-Acceptance & 2 nd Detector Region Designs V.S. Morozov on behalf of the JLEIC detector study group JLEIC Collaboration Meeting, JLab March 29-31, 2016

2. JLEIC Collaboration Meeting, JLab, March 29-31, 20162 Detector requirements – MDI Sessions I & II ̶ Large detector space ̶ Forward tagging ̶ Background Geometric integration – IR Magnet Session ̶ Crossing angle ̶ Matched beam-line footprints ̶ IR magnet dimensions ̶ Ring geometry decoupled from IR design Dynamic requirements – Nonlinear Beam Dynamics Session ̶ Magnet strengths ̶ Optical integration ̶ Non-linear dynamics  Chromaticity compensation  Dynamic aperture Detector Region Design Aspects

3. JLEIC Collaboration Meeting, JLab, March 29-31, 20163 MEIC Layout & Detector Location Warm Electron Collider Ring (3 to 10 GeV) Ion Source Booster Linac Cold Ion Collider Ring (8 to 100 GeV) Two IP locations: One has a new detector, fully instrumented Second is a straight-through, minor additional magnets needed to turn into IP Considerations: Minimize synchrotron radiation –IP far from arc where electrons exit –Electron beam bending minimized in the straight before the IP Minimize hadronic background –IP close to arc where protons/ions exit

4. JLEIC Collaboration Meeting, JLab, March 29-31, 20164 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 Full-Acceptance Detector P. Nadel-Turonski, R. Ent, C.E. Hyde

5. JLEIC Collaboration Meeting, JLab, March 29-31, 20165 Detector Region Layout Forward hadron spectrometer low-Q 2 electron detection and Compton polarimeter p (top view in GEANT4) e ZDC IP e-e- ions ion crab cavities e - crab cavities forward ion detection forward e - detection Compton polarimetry dispersion suppressor/ geometric match spectrometers

6. JLEIC Collaboration Meeting, JLab, March 29-31, 20166 Baseline Electron IR Optics IR region (baseline, has been slightly optimized since) –Final focusing quads with maximum field gradient ~63 T/m –Four 3m-long dipoles (chicane) with 0.44 T @ 10 GeV for low-Q2 tagging with small momentum resolution, suppression of dispersion and Compton polarimeter IP e-e- forward e - detection region FFQs Compton polarimetry region

7. JLEIC Collaboration Meeting, JLab, March 29-31, 20167 IR design features ̶ Modular design ̶ 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, achromatic optics downstream of IP Baseline Ion IR Optics IP ions match/ beam expansion FFB detector elements geom. match/ disp. suppression match/ beam compression Secondary focus with large D x for improved momentum resolution

8. JLEIC Collaboration Meeting, JLab, March 29-31, 20168 Modular design allows for independent optimization of detector region For example, designing a section with zero dispersion slope ̶ Rearranging dipoles and quadrupoles in the dispersion suppressor ̶ Keeping the beam position and angle at the end point fixed Optimization of Detector Region

9. JLEIC Collaboration Meeting, JLab, March 29-31, 20169 Far-Forward Acceptance for Charged Fragments Δp/p = -0.5 Δp/p = 0.0Δp/p = 0.5 (protons rich fragments) (exclusive / diffractive recoil protons) (tritons from N=Z nuclei) (spectator protons from deuterium) (neutron rich fragments)

10. JLEIC Collaboration Meeting, JLab, March 29-31, 201610 Far-Forward Ion 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  electron beam

11. JLEIC Collaboration Meeting, JLab, March 29-31, 201611 Far-Forward Angular Ion Acceptance –Quad apertures = 9, 9, 7 T / (  By /  x @ 100 GeV/c), dipole aperture = -30/+50  40 cm –Uniform distribution of  1  in x and y angles around proton beam at IP for a set of  p/p –The circle indicates neutrals’ cone  electron beam  p/p = -0.5  p/p = 0  p/p = 0.5 neutrons

12. JLEIC Collaboration Meeting, JLab, March 29-31, 201612 Far-Forward Ion Acceptance for Neutrals Transmission of neutrals with initial x and y angular spread vs peak field –Quad apertures = B max / (fixed field gradient @ 100 GeV/c) –Uniform neutral particle distribution of  1  in x and y angles around proton beam at IP –Transmitted particles are indicated in blue (the circle outlines  0.5  cone) 6 T max 9 T max 12 T max  electron beam

13. JLEIC Collaboration Meeting, JLab, March 29-31, 201613 Ion 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  electron beam ±10  @ 60 GeV/c |  p/p| > 0.005 @  x,y = 0

14. JLEIC Collaboration Meeting, JLab, March 29-31, 201614 Ion Momentum & Angular Resolution –Protons with different  p/p launched with  x spread around nominal trajectory –Resulting deflection is observed 12 m downstream of the dipole –Particles with large deflections can be detected closer to the dipole |  x | > 3 mrad @  p/p = 0  electron beam  electron beam ±10  @ 60 GeV/c

15. JLEIC Collaboration Meeting, JLab, March 29-31, 201615 Forward e - Detection & Pol. Measurement Dipole chicane for high-resolution detection of low-Q 2 electrons Compton polarimetry has been integrated to the interaction region design –same polarization at laser as at IP due to zero net bend –non-invasive monitoring of electron polarization c Laser + Fabry Perot cavity e - beam from IP Low-Q 2 tagger for low-energy electrons Low-Q 2 tagger for high- energy electrons Compton electron tracking detector Compton photon calorimeter Compton- and low-Q 2 electrons are kinematically separated! Photons from IP e - beam to spin rotator Luminosity monitor

16. JLEIC Collaboration Meeting, JLab, March 29-31, 201616 Design of the 2 nd IR can be tailored to experimental needs Adding 2 nd IR in the 2 nd straight ̶ Electron beam line geometry does not change ̶ Beam crossing produced by shaping the ends of ion arcs Adding 2 nd IR in the same straight with 1 st IR ̶ Not preferable from detection point of view but may offer significant advantages for machine design Addition of 2 nd Detector Region ions IP e-e-

17. JLEIC Collaboration Meeting, JLab, March 29-31, 201617 Present detector space ̶ Ions: -3.6 / +7 m ̶ Electrons: -1.6 / +2.4 m Spacing on the upstream ion side is presently about as tight as possible ̶ Independent electron and ion energies and independent detector solenoid strengths require independent windings for individual magnets ̶ The shortest detector space therefore is on the order of -3.6 / +3.6 m (mirror reflection of the upstream side onto the downstream side) For fixed chromaticity, luminosity scales inversely with detector space ̶ Assuming the same chromatic contribution as the primary detector, luminosity can be increased by a factor of ~10.6/7.2 = ~1.5 Substantial increase in total chromaticity ̶ Need to readjust chromaticity compensation scheme: additional compensation blocks in the arcs Additional considerations similar to those for the primary detector ̶ Crabbing ̶ Solenoid compensation ̶ Beta squeeze Detector Space and Luminosity

18. JLEIC Collaboration Meeting, JLab, March 29-31, 201618 Simply take out the 2 Tm spectrometer dipole and 1 m section behind it from the primary detector With the same  *, chromaticities ~10% lower  ~10% luminosity increase 2 nd IR Option I

19. JLEIC Collaboration Meeting, JLab, March 29-31, 201619 Downstream ion side is a mirror reflection of the upstream side The shorter the spectrometer dipole, the higher the dispersion at the end of the straight section: D = (L tot – L dip / 2)  dip 2 nd IR Option II IP 16 m7.2 m 50 mrad

20. JLEIC Collaboration Meeting, JLab, March 29-31, 201620 Conceptual design of the interaction region completed –Interaction region integrated into collider rings –Forward detection requirements fully satisfied Ongoing and future work –Design optimization –Solenoid integration and compensation – IR Session –Crab cavity integration –Detector modeling – MDI Sessions I & II –Polarimetry development –Vacuum and backgrounds – MDI Session II –Injection optics design –Specification of magnet requirements – IR Magnet & NBD Sessions –Engineering design of interaction region magnets – IR Magnet Session –Development of beam diagnostics and orbit correction scheme –Optimization of non-linear dynamics – NBD Session Summary & Outlook