2 nd Muon Collider Design workshop, JLab, Newport News VA December 8-12, 2008 Summary on the Muon Collider Lattice and Interaction Region Design Y.Alexahin f
Jan 19, 2016
2nd Muon Collider Design workshop, JLab, Newport News VA December 8-12, 2008
Summary on the Muon Collider Lattice and Interaction Region Design
Y.Alexahin
f
MC Lattice & IR Design - Y. Alexahin 2nd MCD workshop, JLab, December 12, 2008
The session
INTERACTION REGION Chair, Al Garren
Update on the 'Dipole first' Muon Collider optics (Yuri Alexahin)
Studies for a Muon Collider Optics with non-interleaved sextupole scheme (Eliana Gianfelice-Wendt )
Considerations on Optimized IR Design (Yaroslav Derbenev)
Beam Induced Detector Backgrounds for a Muon Collider (Steve Kahn)
Low-beta Region Muon Collider Detector (Mary Anne Cummings)
The first two talks gave an update on the existing MC designs,
Yaroslav formulated principles on which a new design will be based (“bend everything!”)
Steve reviewed previous work and plans on detector shielding from secondaries
Mary Anne outlined new ideas in the detector design
MC Lattice & IR Design - Y. Alexahin 2nd MCD workshop, JLab, December 12, 2008
Basic parameters
Oide (modified) “Dipole first”
Beam energy, GeV 750 750
Number of IPs 1 2
Circumference, km 4.9 3.1
*, cm 1 1
_max, km 275 32
Momentum compaction 1.8e-4 5.5e-5
800MHz RF voltage*, GV 1.56 0.31
Momentum acceptance, % 0.75 0.63
Tunes 30.55/30.45 42.1/41.1
DA, for =25m >5 ~3
-------------------------------------------------------------------------------
*) for energy spread E=0.2% and bunch length s=1cm
2
s
E
RFcRF f
cERV
- one more reason to reduce circumference!
MC Lattice & IR Design - Y. Alexahin 2nd MCD workshop, JLab, December 12, 2008
IR Optics
x y
Dx DDx/50
Wx
Wy
“Dipole first” modified Oide
MC Lattice & IR Design - Y. Alexahin 2nd MCD workshop, JLab, December 12, 2008
Momentum Acceptance
c
p
p
Qy
Qx
“Dipole first” modified Oide
MC Lattice & IR Design - Y. Alexahin 2nd MCD workshop, JLab, December 12, 2008
Nonlinear Detuning and Dynamic Aperture
0 50 100 150 200 2500
50
100
150
200
250
CSIx [m]
CSIy [m]
Normalized anharmonicities:
dQ1/dE1 = 0.25242152E+08
dQ1/dE2 = 0.19616977E+08
dQ2/dE2 = 0.18515914E+08
“Dipole first” modified Oide
MC Lattice & IR Design - Y. Alexahin 2nd MCD workshop, JLab, December 12, 2008
Status of the lattice design
x
yx,
“Dipole first” optics provides necessary DA for the medium-emittance option, but only marginal for HE
Modified Oide lattice has sufficient DA for the high-emittance option, but the circumference is too large.
Next step - to combine the best of the two:
There is still no design suitable for the low emittance option, hopefully the approach outlined by Yaroslav will lead to one.
But it must include crossing angle and all the complications associated with it!
“Dipole first” lattice has the first 7.5T dipole 2.5m from the IP.
- Will it complicate or help to protect the detector by sweeping the secondaries?
- How the dipole fringe field will affect the detector performance?
Programs outlined by Steve and Mary Anne will provide the guidance
MC Lattice & IR Design - Y. Alexahin 2nd MCD workshop, JLab, December 12, 2008
Detector Protection (S.Kahn)
Detector schematics
MC Lattice & IR Design - Y. Alexahin 2nd MCD workshop, JLab, December 12, 2008
Bethe-Heitler Muon Trajectories for the 2×2 TeV Collider
Muon pair production at beam pipe for exampleNNeNeN (electrons are more likely to hit beam pipe).
MC Lattice & IR Design - Y. Alexahin 2nd MCD workshop, JLab, December 12, 2008
IP Configuration Parameters
6.5 m8 m7 mDistance to First Quad
0.5 cm0.8 cmRiris
1.1 m1.1 m80 cmMin Aperture Point
3 cm3 cm6 cmOpen Space to IP
20º20º20ºShield Angle
2×2 TeV250×250 GeV50×50 GeVParameter
MC Lattice & IR Design - Y. Alexahin 2nd MCD workshop, JLab, December 12, 2008
Future Plans
• We need to start to examine beam related backgrounds produced by currently in vogue IP designs.– This is expected to take a fair amount of work.– We would have to optimize the current IP design as previously done to
reduce backgrounds.• Compare to previous designs.
• We need to reexamine the forward/backward shielding.– Can we reduce the 20º blind cone angle by instrumenting the cone to
identify electromagnetic punch-through background so that it can be ignored.
– Can we instrument the core to identify muons. This would help enormously in identifying multi-lepton channels produced by SUSY.
– Can we instrument the low beta forward-backward regions.• Mary Anne will tell us more about that.
MC Lattice & IR Design - Y. Alexahin 2nd MCD workshop, JLab, December 12, 2008
Low-beta Region Muon Collider Detector (Mary Anne Cummings)
Last serious design effort was Snowmass 1996Lack of coverage in the forward/backward angular region:
Shielding is necessary against electrons from muon decays The area < 20 degrees for/back was inert material (tungsten), but possibility down to < 9 degrees considered Serious limitation to possible physicso Top production in forward regions as CoM energy goes upo Asymmetries are more pronounced in forward regionso Z’ => ttbaro Final states with many fermions (like ordinary SM tt-events) are hardly ever
contained in the central detectorAdvances in detector technologies have made extending the forward
reach possible – minimizing a competitive disadvantage with linear colliders
MC Lattice & IR Design - Y. Alexahin 2nd MCD workshop, JLab, December 12, 2008
Forward Calorimetry
MC Lattice & IR Design - Y. Alexahin 2nd MCD workshop, JLab, December 12, 2008
NIU Calorimeter R & D: Calorimeter Tiles
(a): Examples of plastic scintillator tiles for use in calorimeters; (b): Array of scintillating tiles arranged on 1m x 1m plate of a prototype CALICE hadron calorimeter, built by the NIU group.
Candidate for “instrumented shielding” that will comprise a forward region muon collider detector, addressing the challenges of viability and particle ID requirements
a) b)
MC Lattice & IR Design - Y. Alexahin 2nd MCD workshop, JLab, December 12, 2008
Major Issues for Phase I SBIR
• Scope of Muons, Inc. SBIR Phase I: establish the viability of
“instrumented shielding” to extend the physics coverage of a Muon Collider Detector by studying the
The limits of detector performance (e.g., cell occupancy, efficiency) in the forward interaction region as a function of muon collider bunch intensity and luminosity.
The shielding requirements for all detectors, especially those that might be affected by the instrumentation of the tungsten cone.
The optimization of the collider parameters and low beta insertion designs to minimize the beam-related backgrounds that get into the detector.
MC Lattice & IR Design - Y. Alexahin 2nd MCD workshop, JLab, December 12, 2008
Summary
With the present level of understanding it seems possible:
=1cm
c ~ 10-5 -10-4
momentum acceptance ±1%
Dynamic aperture ~ 5 for N=25 m (HE option)
Circumference ~3km
(all at the same time)
To proceed further to a realistic design a close collaboration between lattice designers and detector, energy deposition and magnet technology groups is a must.
I hope we’ll establish such collaboration with MuonsInc people.