MEIC Detector and IR Integration Vasiliy Morozov, Charles Hyde, Pawel Nadel-Turonski MEIC Detector and IR Design Mini-Workshop, October 31, 2011

Central detector EM Calorimeter Hadron Calorimeter Muon Detector EM Calorimeter Solenoid yoke + Muon Detector TOF HTCC RICH Cerenkov Tracking 2 m 3 m 2 m 4-5 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 FFQs 50 mrad 0 mrad ion dipole w/ detectors (approximately to scale) ions electrons IP ion FFQs 2+3 m 2 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 0.5 o beyond ion FFQs and in arcs. Detect particles with angles down to 0.5 o before ion FFQs. Need up to 2 Tm dipole in addition to central solenoid. 7 m

Interaction Region: Ions β x * = 10 cm β y * = 2 cm β y max ~ 2700 m Final Focusing Block (FFB) Chromaticity Compensation Block (CCB) Beam Extension Section Whole Interaction Region: 158 m Distance from the IP to the first FF quad = 7 m Quad strengths of FF triplet at 100 GeV/c – Q 1 = T/m – Q 2 = 64.5 T/m – Q 3 = T/m ±10 cm quad aperture allows clear line of sight at ±0.5  CCB next to FFB for chromatic correction 7 m

Tracking Through FFB Maximum excursion in X plane for positive particle At lower  p/p values, maximum  x occurs in the 2 nd quad; at higher  p/p values, maximum  x is in the 3 rd quad  p/p is equivalent to  (q/m), i.e. p after d break up behaves as  p/p = -0.5

Maximum Orbit Excursion vs Momentum Offset Quad aperture = Field at the pole tip / Maximum field gradient

G4beamline Simulations GEANT 4 toolkit for beam line simulations Realistic simulations of complete system at later design stages Not very well suited for optimization tasks  p/p = -0.5  p/p = 0.0  p/p = 0.5

Detector Solenoid 4 T field at the center, 5 m long, 2.5 m inner radius, IP 2 m downstream from edge Realistic solenoid model: many infinitely-thin current sheets evenly spread radially Ion beam at IP is at 50 mrad to the solenoid axis 60 GeV/c proton orbit distortion at the entrance into the spectrometer dipole 5 m downstream of IP assuming proton and electron orbits are in horizontal plane at IP –  x = 250 mm,  y = -8.9 mm,  p x /p = 0.050,  p y /p =

Correcting Orbit Distortion Important to correct vertical offset and angle to make the orbit flat in the ring Tricky because no space for corrector dipoles between IP and downstream FFB Suggested solution: – Rotate the interaction plane by a certain angle around the solenoid axis – Rotate the spectrometer dipole around its axis by a certain angle Other options – Let the ion orbit shift inside the FFB quads and correct it downstream – Install FFB quads at an angle to keep the distorted orbit centered – Make the spectrometer dipole a few independent dipoles used as correctors – Shift the IP – ?? – Combination of some of the above options

Suggested Solution Was shown in simulations to correct the vertical orbit distortion for 60 GeV/c protons with 50 mrad crab crossing angle but should work in general The spectrometer dipole is modeled as a 1 m long box with 2 T uniform vertical field The rotation angles are first obtained analytically and then checked in simulation The required rotation of the interaction plane around the solenoid axis is 36.8 mrad – Can be done by corrector dipoles in front of the solenoid where there is space The required spectrometer dipole rotation around its axis is mrad – Perhaps can be implemented without mechanical rotation by using additional coil windings in the dipole to rotate the field – Dipole axis lies in horizontal plane – For the dipole model used, the correction is not sensitive to the dipole axis alignment in horizontal plane In the solenoid model used, the solenoidal fringe field extends into the dipole and was not taken into account when calculating the correction, therefore there is a small effect from the fringe field, field maps should be used for more accurate simulations

Corrected Orbit

Final Focusing Block Distance from the IP to the first quad = 7 m Quadrupole lengths: L 1 = L 2 = L 3 = 1.5 m Quad 100 GeV/c: Q 1 = T/m, Q 2 = 64.5 T/m, Q 3 = T/m

Tracking through FFB

FFB Acceptance Study 60 GeV/c proton beam originates at the interaction point Beam particles uniformly distributed within a horizontal (vertical) angle of  1  around the beam trajectory and  p/p of  0.7 Quad aperture radii = 10 cm  6 T / (field 100 GeV/c) Particles that pass through the FFB shown in blue

Optimized FFB Distance from the IP to the first quad = 7 m Quadrupole lengths: L 1 = 1.2 m, L 2 = 2.4 m, L 3 = 1.2 m Quad 100 GeV/c: Q 1 = T/m, Q 2 = 41.3 T/m, Q 3 = T/m Pawel Nadel-Turonski & Alex Bogacz

Tracking through Optimized FFB Each quad aperture = B max / (field 100 GeV/c)

Optimized FFB Acceptance 60 GeV/c protons, each quad aperture = B max / (field 100 GeV/c) 6 T max 9 T max 12 T max

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 100 GeV/c)

Complete System 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 FFB Big spectrometer dipole – 4 m downstream of the FFB, sector bend, 3.5 m long, 60 mrad bending angle,  20 cm square aperture

System Acceptance for Neutrons Neutrons uniformly distributed within  1  horizontal & vertical angles around 60 GeV/c proton beam Each quad aperture = 6 T / (field 100 GeV/c)

System Acceptance for  p/p = -0.5 Protons with  p/p = -0.5 uniformly distributed within  1  horizontal & vertical angles around the nominal 60 GeV/c proton beam trajectory Each quad aperture = 6 T / (field 100 GeV/c)

System Acceptance for  p/p = 0.0 Protons with  p/p = 0.0 uniformly distributed within  1  horizontal & vertical angles around the nominal 60 GeV/c proton beam trajectory Each quad aperture = 6 T / (field 100 GeV/c)

System Acceptance for  p/p = +0.5 Protons with  p/p = +0.5 uniformly distributed within  1  horizontal & vertical angles around the nominal 60 GeV/c proton beam trajectory Each quad aperture = 6 T / (field 100 GeV/c)

Transverse Coordinates for  p/p = GeV/c protons, each quad aperture = 6 T / (field 100 GeV/c) Blue: within cone with polar angle  0.5  At the entrance into the big dipoleAt the exit from the big dipole

Transverse Coordinates for  p/p = GeV/c protons, each quad aperture = 6 T / (field 100 GeV/c) Blue: within cone with polar angle  0.5  At the entrance into the big dipoleAt the exit from the big dipole

Transverse Coordinates for  p/p = GeV/c protons, each quad aperture = 6 T / (field 100 GeV/c) Blue: within cone with polar angle  0.5  At the entrance into the big dipoleAt the exit from the big dipole

Separation of Electron and Ion Beams

Beam Parallel after FFB FFB: quad lengths = 1.2, 2.4, 1.2 m, quad 100 GeV/c = -79.6, 41.1, 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

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

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| >  x,y = 0

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

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  p/p = 0

Beam Focused after FFB FFB: quad lengths = 1.2, 2.4, 1.2 m, quad 100 GeV/c = -89.0, 51.1, 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 & Charles Hyde

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

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| >  x,y = 0

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

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 | >  p/p = 0 |  x | > 3  p/p = 0

Future Plans 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. Hybrid permanent / electro magnet electron FFB design? (Pawel Nadel-Turonski & Alex Bogacz) Evaluation of the engineering aspects, such as magnet parameters, electron and ion beam line separation, etc.