the high-emittance muon collider
DESCRIPTION
The High-Emittance Muon Collider. David Neuffer June 2009 Low Emittance Muon Collider Workshop Preview. Outline. Introduction Motivation Scenario Outline and Features Parameters Proton Driver Front End Accelerator Collider Upgrade Path(s) to Low-Emittance Muon Collider. - PowerPoint PPT PresentationTRANSCRIPT
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The High-Emittance Muon The High-Emittance Muon ColliderCollider
David Neuffer
June 2009Low Emittance Muon Collider Workshop Preview
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OutlineOutline
Introduction Motivation
Scenario Outline and Features Parameters Proton Driver Front End Accelerator Collider
Upgrade Path(s) to Low-Emittance Muon Collider
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Motivation- E. EichtenMotivation- E. Eichten
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Other physics Other physics
Higgs at high energy σ ≈ 0.6pb
0.01 fb-1 is 1030 for 107s need more to sweep
nearby energy First
SuperDimensional DarkMatterEnergy HyperSymmetric Particle?? σ > pb !!
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2A
2 TeV
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HEMC Parameters HEMC Parameters
Parameter Symbol Value
Proton Beam Power Pp 2.4 MW
Bunch frequency Fp 60 Hz
Protons per bunch Np 3×1013
Proton beam energy Ep 8 GeV
Number of muon bunches nB 12
+/-/ bunch N 1011
Transverse emittance t,N 0.003m
Collision * * 0.05m
Collision max * 10000m
Beam size at collision x,y 0.013cm
Beam size (arcs) x,y 0.55cm
Beam size IR quad max 5.4cm
Collision Beam Energy E+,E_ 1 TeV (2TeV total)
Storage turns Nt 1000
Luminosity L0 4×1030
Proton Linac 8 GeV
Accumulator,Buncher
Hg target
Linac
RLAs
Collider Ring
Drift, Bunch, Cool
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Proton DriverProton Driver
Proton Driver is variant of Project X Other variations possible 8 GeV at Fermilab
8 GeV SRF linac , 15 Hz 1.2×1014/cycle
Accumulate, Bunch to form 4 bunches 3×1013/bunch
• εN6π =120π mm-mrad, BF = 0.005
• δν = 0.4 extract at 60Hz
Proton Linac 8 GeV
Accumulator,Buncher
Drift, Bunch, Cool
Hg target
Linac
RLAs
Collider Ring
Detector
p tot
2F N
3r N
2 B
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Solenoid lens captureSolenoid lens capture
Target is immersed in high field solenoid Particles are trapped in Larmor orbits
B= 20T -> ~2T Particles with p < 0.3 BsolRsol/2=0.225GeV/c are
trapped π→μ Focuses both + and – particles Drift, Bunch and phase-energy rotation
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High-frequency Buncher and High-frequency Buncher and φφ-E -E RotatorRotator
Drift (π→μ) “Adiabatically” bunch beam first (weak 320 to 240 MHz rf)
Φ-E rotate bunches – align bunches to ~equal energies 240to 202 MHz, 15MV/m
Cool beam 201.25MHz
10 m ~50 m
FE
Targ et
Solenoid Drift Buncher Rotator Cooler
~30m 36m ~80 m
p
π→μ
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Adiabatic Buncher; Adiabatic Buncher; φφ-E rotation-E rotation Set rf phase to be zero for
reference energies Spacing is N rf
rf increases
gradually increase rf gradient
Match to rf= ~1.5m at end:
After bunching rephase rf so that higher energy bunches accelerate, low energy bunches
Finish when bunch energies are aligned in E Transfer to cooling
Captures both μ+ and μ-
born from same proton bunch
Example: rf : 0.901.5m
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Bunch train for ColliderBunch train for Collider
Drift, buncher, rotator to get “short” bunch train (nB = 10): 217m ⇒ 125m 57m drift, 31m buncher, 36m rotator Rf voltages up to 15MV/m (×2/3)
Obtains ~0.1 μ/p8 in ref. acceptance At < 0.03, AL <0.2 Choose best 12 bunches
• ~0.008 μ/p8 per bunch
• ~0.005 μ/p8 in acceptance
3 × 1013 protons 1.5× 1011
μ/bunch in acceptance
εt,rms, normalized ≈ 0.003m (accepted μ’s)
εL,rms, normalized≈ 0.034m (accepted μ’s)
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Simulations (NSimulations (NBB=10)=10)
-30m 30m
500 MeV/c
0
Drift andBunch
s = 89ms = 1m
Rotate
s = 125m s = 219m
Cool
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HEMC collider bunchesHEMC collider bunches
Scenario is unoptimized ~60% of μ’s in best 12
bunches ~75% in best 16
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Acceleration-RLA’s ? Acceleration-RLA’s ?
1.2 GeV/pass7.2 GeV
1.8 GeV244 MeV
300 m
160 m
5 GeV/pass
528 m32.5GeV
7 pass Ef
E0
= 30Dogbone RLA II example
Linac
140 GeV/pass
32.5 GeV
1000 GeV
Dogbone geometry is long. (140 GeV @20MV/m is 7km.)Racetrack is more compact.
A. Bogacz – Dogbone RLAs
Beam is probably too big for 1300MHz.800 MHz - OK
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Collider RingCollider Ring
12 bunches of μ+ and μ-
1011 μ/bunch
β* = 3 to 10 cm σ= 0.01 to 0.016cm
βmax = 10000m σ=5.5cm (1TeV) IR quads are large aperture (20cm
radius)
εL =0.012 eV-s δE ~0.12 GeV if σz = 3cm δE/E = 10-4
Collider is not beam-beam limited Δν=0.000036
,4 beam beamN rms
N r
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Upgrade pathUpgrade path
More cooling εt,N→ 0.0005, β*→1cm
L→1032
Bunch recombination 12→1 L →1033
More cooling low emittance εt,N→ 0.00003, β*→0.3cm
L→1034
More Protons 2.4→5MW or more L→1035
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ConclusionsConclusions
An Initial Muon Collider (0.5 to 4 TeV) with low luminosity could be constructed, particularly if motivated by a clear physics goal. Uses trains of μ+ and μ- bunches for acceleration and storage (~ 20m trains) L= ~4×1030 cm-2s-1
needs little cooling does need front end (captures both μ+ and μ-)
Could be upgraded to high-luminosity more cooling smaller β* bunch recombination
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First First μμ Collider may not be perfect Collider may not be perfect ……