Detector / Interaction Region Integration

transcript

Vasiliy Morozov, Charles Hyde, Pawel Nadel-Turonski

Joint CASA/Accelerator and Nuclear Physics MEIC/ELIC Meeting February 3, 2012

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Motivation

Pawel Nadel-Turonski

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Central detector

Solenoid yoke + Muon DetectorTOF

HCerenkov

Tracking

2 m 3 m 2 m

Solenoid yoke + Hadronic Calorimeter

MEIC Primary “Full-Acceptance” Detector

Distance IP – electron FFQs = 3.5 m Distance IP – ion FFQs = 7.0 m (Driven by push to 0.5 detection before ion FFQs)

Pawel Nadel-Turonski & Rolf Ent

solenoid

electron FFQs50 mrad

0 mrad

ion dipole w/ detectors

(approximately to scale)

ionselectrons

ion FFQs

2+3 m2 m

Make use of the (50 mr) crossing angle for ions!

detectors

Central detector, more detection space in ion direction as particles have higher momenta

Detect particles with angles below 0.5o beyond ion FFQs and in arcs.

Detect particles with angles down to 0.5o before ion FFQs.Need up to 2 Tm dipole in addition to central solenoid.

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GEANT4 Model• Detector solenoid

– 4 T field at the center, 5 m long, 2.5 m inner radius, IP 2 m downstream from edge • Small spectrometer dipole in front of the FFB

– 1.2 T (@ 60 GeV/c), 1 m long, hard-edge uniform field – Interaction plane and dipole are rotated around z to compensate orbit offset

• FFB• Big spectrometer dipole

– 4 m downstream of the FFB, sector bend, 3.5 m long, 60 mrad bending angle (12 Tm, 3.43 T @ 60 GeV/c), 20 cm square aperture

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Separation of Electron and Ion Beams

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Beam Parallel after FFB• FFB: quad lengths = 1.2, 2.4, 1.2 m, quad strengths @ 100 GeV/c = -79.6, 41.1, -23.1 T/m• 1.2 Tm (@ 60 GeV/c) outward-bending dipole in front of the final focus• 12 Tm (@ 60 GeV/c) inward-bending dipole 4 m downstream of the final focus

Pawel Nadel-Turonski & Alex Bogacz

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FFB Acceptance• 60 GeV/c protons, each quad aperture = B max / (field gradient @ 100 GeV/c)

6 T max 9 T max 12 T max

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FFB Acceptance for Neutrons

6 T max 9 T max 12 T max

• Neutrons uniformly distributed within 1 horizontal & vertical angles around 60 GeV/c proton beam

• Each quad aperture = B max / (field gradient @ 100 GeV/c)

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System Acceptance at 6 T max Field• Uniform distribution horizontally & vertically within 1 around 60 GeV/c protons• Each quad aperture = 6 T / (field gradient @ 100 GeV/c)

p/p = 0 neutrons

p/p = -0.5 p/p = 0.5

electron beam electron beam

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Momentum & Angle Resolution• Beam parallel after the final focus• Protons with p/p spread launched at different angles to nominal 60 GeV/c trajectory• Red hashed band indicates 10 beam stay-clear

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Momentum & Angle Resolution• Beam parallel after the final focus• Protons with p/p spread launched at different angles to nominal 60 GeV/c trajectory• Red hashed band indicates 10 beam stay-clear

|p/p| > 0.03 @ x,y = 0

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Momentum & Angle Resolution• Beam parallel after the final focus• Protons with different p/p launched with x spread around nominal 60 GeV/c trajectory• Red hashed band indicates 10 beam stay-clear

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Momentum & Angle Resolution• Beam parallel after the final focus• Protons with different p/p launched with x spread around nominal 60 GeV/c trajectory• Red hashed band indicates 10 beam stay-clear |x| > 2 mrad @ p/p = 0

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Beam Focused after FFB• FFB: quad lengths = 1.2, 2.4, 1.2 m, quad strengths @ 100 GeV/c = -89.0, 51.1, -35.7 T/m• 1.2 Tm (@ 60 GeV/c) outward-bending dipole in front of the final focus• 12 Tm (@ 60 GeV/c) inward-bending dipole 4 m downstream of the final focus

Pawel Nadel-Turonski & Charles Hyde

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System Acceptance at 6 T max Field• Uniform distribution horizontally & vertically within 1 around 60 GeV/c protons• Each quad aperture = 6 T / (field gradient @ 100 GeV/c)

p/p = 0 neutrons

p/p = -0.5 p/p = 0.5

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System Acceptance with Varied Quad Fields• Uniform distribution horizontally & vertically within 1 around 60 GeV/c protons• Quad apertures = 9, 9, 6 T / (field gradient @ 100 GeV/c)

p/p = -0.5

p/p = 0

p/p = 0.5

neutrons

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Detector / IR Layout

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Momentum & Angle Resolution• Beam focused after the FFB• Protons with p/p spread launched at different angles to nominal 60 GeV/c trajectory• Red hashed band indicates 10 beam stay-clear

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Momentum & Angle Resolution• Beam focused after the FFB• Protons with p/p spread launched at different angles to nominal 60 GeV/c trajectory• Red hashed band indicates 10 beam stay-clear |p/p| > 0.005 @ x,y = 0

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Momentum & Angle Resolution• Beam focused after the FFB• Protons with different p/p launched with x spread around nominal 60 GeV/c trajectory• Red hashed band indicates 10 beam stay-clear

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Momentum & Angle Resolution• Beam focused after the FFB• Protons with different p/p launched with x spread around nominal 60 GeV/c trajectory• Red hashed band indicates 10 beam stay-clear |x| > N/A @ p/p = 0

|x| > 3 mrad @ p/p = 0

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Electron FFB• Quads nearest to IP are inside strong solenoid fringe field

either permanent-magnet or super-conducting quadrupoles• Consider hybrid electron FFB design (P. Nadel-Turonski & A. Bogacz):

first two quads are permanent-magnet, subsequent quads are super-conducting (smaller OD)

• Outer radius of a permanent-magnet quad (M. Sullivan) depending on the inner radius and field gradient:

rinner = 20 mm, G = 15 T/m router = 23.4 mm• Permanent-magnet quad

– can be placed closer to IP– covers smaller solid angle greater acceptance

1( ) 1 ( / )( ) 2.046

r m G T mr m

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Hybrid Electron FFB Optics at 3 GeV/c• Drift lengths: 3, 0.25, 0.25, 1, 0.2 m• Quad lengths: 0.5, 0.5, 0.5, 0.5, 0.3 m• Quad inner radii: 2, 2, 2, 4, 4 cm; quad outer radii: 3, 3, 9, 11, 11 cm• Quad strengths: -15.0, 15.0, -5.87, 7.70, -8.48 T/m

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Detector / IR Layout

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Upstream Ion / Downstream Electron Side• Electron FFB

– 4 m distance to IP?– 1 polar angle acceptance– Superconducting quads (solenoid fringe field, small size, large aperture)– Electron beam focused inside spectrometer dipole?

• Ion FFB– First quad immediately after first electron quad at ~4.5-5 m – Ion quads interleaved with electron quads

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Conclusions• Completed the study of forward ion tagging, a few design choices to be made

• Request to nuclear physics– Come up with specs for detector resolution requirements – this will help to

motivate and make the design choices, in particular, quantify the advantages of focused vs parallel downstream ion beam

• To do list– Design forward electron tagging and upstream ion FFB– Design optimization, e.g. acceptance of the FFB using genetic algorithm– Integration into the ring optics, such as decoupling, dispersion

compensation, understanding effect of large-aperture quadrupoles on the optics, etc.

– Evaluation of the engineering aspects, such as magnet parameters, electron and ion beam line separation, etc.

Detector / Interaction Region Integration

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