1. Muon Accelerator Program - MAP
MUON COLLIDER R&D
Steve Geer
Accelerator Physics Center
Fermi National Accelerator Laboratory
Accelerator Seminar
SLAC., March 24, 2011 m+ m- n
Muon Accelerator Program - MAP

2. Accelerator Seminar SLAC 24 March, 2011
PHYSICS LANDSCAPE
STEVE GEER
Accelerator Seminar SLAC March, 2011

3. Accelerator Seminar SLAC 24 March, 2011
DECISION TREE
Pierre Oddone
STEVE GEER
Accelerator Seminar SLAC March, 2011

4. MUON COLLIDER MOTIVATION
If we can build a muon collider, it is an attractive multi-TeV lepton collider option because muons don’t radiate as readily as electrons (mm / me ~ 207):
- COMPACT Fits on laboratory site
- MULTI-PASS ACCELERATION
Cost Effective operation & construction
- MULTIPASS COLLISIONS IN A RING (~1000 turns) Relaxed emittance requirements & hence relaxed tolerances - NARROW ENERGY SPREAD Precision scans, kinematic constraints
- TWO DETECTORS (2 IPs) - DTbunch ~ 10 ms … (e.g. 4 TeV collider)
Lots of time for readout Backgrounds don’t pile up
- (mm/me)2 = ~40000
Enhanced s-channel rates for Higgs-like particles
A 4 TeV Muon Collider would fit on the Fermilab Site
COST
PHYSICS
STEVE GEER
Accelerator Seminar SLAC March, 2011

5. ENERGY SPREAD Beamstrahlung in any e+e- collider E/E  2 STEVE GEER
Accelerator Seminar SLAC March, 2011

6. Accelerator Seminar SLAC 24 March, 2011
l+l- → Z’ → m+m-
ENERGY SCAN
m+m- with ISR+BStr (Eichten)
e+e- with ISR
e+e- with ISR+BStr
Z’ Line shape
EVENT RATE
1600
1200
800
400
√s (GeV)
2900
2950
3000
3050
3100
STEVE GEER
Accelerator Seminar SLAC March, 2011

7. Accelerator Seminar SLAC 24 March, 2011
CHALLENGES
Muons are produced as tertiary particles. To make enough of them we must start with a MW scale proton source & target facility.
Muons decay  everything must be done fast and we must deal with the decay electrons (& neutrinos for CM energies above ~3 TeV).
Muons are born within a large 6D phase-space. For a MC we must cool them by O(106) before they decay  New cooling technique (ionization cooling) must be demonstrated, and it requires components with demanding performance (NCRF in magnetic channel, high field solenoids.)
After cooling, beams still have relatively large emittance.
STEVE GEER
Accelerator Seminar SLAC March, 2011

8. MUON COLLIDER SCHEMATIC
√s = 3 TeV
Circumference = 4.5km L = 3×1034 cm-2s-1 m/bunch = 2x1012
s(p)/p = 0.1%
eN = 25 mm, e//N=70 mm
b* = 5mm
Rep Rate = 12Hz
1021 muons per year that fit within the acceptance of an accelerator:
eN=6000 mm
e//N=25 mm
Proton source: Example: upgraded PROJECT X (4 MW, 2±1 ns long bunches)
STEVE GEER
Accelerator Seminar SLAC March, 2011

9. Muon Collider cf. Neutrino Factory
In present MC baseline design, Front End is same as for NF
STEVE GEER
Accelerator Seminar SLAC March, 2011

10. A DECADE OF PROGRESS NF Feasibility Studies
Successful completion of NF feasibility studies 1, 2, 2a, & International Scoping Study; launching of the ongoing International Design Study for a NF (IDS-NF)
Solid basis for planning the MC Design Feasibility Study (DFS)
Real progress on understanding how to make enough muons, capture them into bunches, reduce their energy spread, and begin to reduce their transverse phase space (ionization cooling).
IDS-NF community plans to produce a Reference Design Report (RDR) in ~ 2 years.
Interim Design Report (IDR) has just been finalized, and is to be reviewed by an ECFA sub-panel May 5-6, 2011
STEVE GEER
Accelerator Seminar SLAC March, 2011

11. A DECADE OF PROGRESS Front-End Design
p± → mn
Front-end uses NCRF in a lattice of solenoids
Parameter
Drift
Buncher
Rotator
Cooler
Length (m)
56.4
31.5 36 75
Focusing (T) 2
2.5 (ASOL)
RF f (MHz)
360 ® 240
240 ® 202
201.25
RF G (MV/m)
0 ® 15 15 16
Total RF (V)
126
360
800
STEVE GEER
Accelerator Seminar SLAC March, 2011

12. A DECADE OF PROGRESS Front-End Simulations
Neuffer
With a 4MW proton source, this will enable O(1021) muons/year to be produced, bunched, cooled & fit within the acceptance of an accelerator.
STEVE GEER
Accelerator Seminar SLAC March, 2011

13. A DECADE OF PROGRESS Successful completion of MERIT
Proof-of-principle demonstration of a liquid Hg jet target in high-field solenoid ran at CERN PS in Fall 2007.
Successfully demonstrated a 20m/s liquid Hg jet injected into a 15 T solenoid, & hit with a suitably intense beam (115 KJ / pulse !).
Results suggest this technology OK for beam powers up to 8 MW with rep. rate of 70Hz !
1 cm
Hg jet in a 15 T solenoid
Measured disruption length = 28 cm
STEVE GEER
Accelerator Seminar SLAC March, 2011

14. A DECADE OF PROGRESS Ionization Cooling
TRANSVERSE COOLING: Muons lose energy by in material (dE/dx). Re-accelerate in longitudinal direction  reduce transverse emittance. Coulomb scattering heats beam  low Z absorber. Hydrogen is best, but LiH also OK for the early part of the cooling channel.
6D COOLING: Mix transverse & longitudinal degrees of freedom during cooling. Can be done in helical solenoids.
FINAL COOLING: To get the smallest achievable transverse emittance, over-cool the longitudinal emittance, and then work only on the transverse emittance letting the longitudinal phase space grow.
εt,,N
(m)
Liq. H2 RF
High Field (HTS)
Solenoids
STEVE GEER
Accelerator Seminar SLAC March, 2011

15. A DECADE OF PROGRESS Ionization cooling concepts & simulations
Development of a cooling channel design to reduce the 6D phase space by a factor of O(106) → luminosity O(1034) cm-2 s-1
Some components beyond state-of-art:
Very high field HTS solenoids & High gradient RF cavities operating in few Tesla fields
Challenging are the solenoids in the last stages of cooling:
Original design needed 50 T solenoids. Recent improvements suggest 30 T sufficient.
Palmer
30T
HTS
STEVE GEER
Accelerator Seminar SLAC March, 2011

16. PROGRESS THIS YEAR Ionization cooling concepts & simulations
STEVE GEER
Accelerator Seminar SLAC March, 2011

17. A DECADE OF PROGRESS MuCool Test Area
MTA built at end of FNAL Linac for ionization cooling component testing 5 T magnet, RF power at 805 MHz & 201 MHz, clean room, LH2 handling capability, 400 MeV beam from linac.
FIRST BEAM IN MTA 28 FEBRUARY !
42 cm Æ Be RF window (LBNL)
High Pressure RF Cavity (FNAL & Muons Inc.)
201 MHz cavities (LBNL et al.)
Liq. H2 absorber (KEK)
STEVE GEER
Accelerator Seminar SLAC March, 2011

18. A DECADE OF PROGRESS Muon Ionization Cooling Experiment (MICE)
Multi-stage experiment at RAL to be completed ~2014
- Tests short cooling section, in muon beam, measuring the muons before & after the cooling section. one at a time.
- Learn about cost, complexity, & engineering issues associated with cooling channels.
Vary RF, solenoid & absorber param- eters & demonstrate ability to simulate response of muons
Spectro- meter
Cooling section
Spectro- meter
Muon Beam
MICE – upstream beamline
STEVE GEER
Accelerator Seminar SLAC March, 2011

19. A DECADE OF PROGRESS Muon Ionization Cooling Experiment (MICE)
Spectrometer Solenoid
Tracker in cosmic ray test stand
RF Cavity
Liq. H2 Absorber
MICE HALL
STEVE GEER
Accelerator Seminar SLAC March, 2011

20. A DECADE OF PROGRESS Collider Ring
Emittances are large, but the muons circulate for only ~1000 turns before they decay.
- First lattice designs exist.
Need high field dipoles & quadrupoles that operate in large muon decay backgrounds
Have studied open mid-plane magnet design (radiation & heat loads, field non-uniformity & affect on lattice performance) → looks OK.
- More engineering studies needed.
√s=1.5 TeV
MARS energy deposition map for a 1.5 TeV collider dipole
STEVE GEER
Accelerator Seminar SLAC March, 2011

21. A DECADE OF PROGRESS Detector Backgrounds
Muon Collider detector backgrounds studied ~10 yrs ago ( ). Most detailed work done for a s=4 TeV Collider.
The electron decay angles from m→enn are O(10) mradians . Electrons typically stay inside beampipe for ~6m. Hence decay electrons born within a few meters of the IP are benign.
Shielding strategy: sweep the electrons born further than ~6m from the IP into ~6m of shielding.
MARS & GEANT studies gave consistent results. After optimization of shielding, for  s=4 TeV, particle densities in inner detectors similar to 1034 cm-2 s-1 .
STEVE GEER
Accelerator Seminar SLAC March, 2011

22. A DECADE OF PROGRESS New Detector Studies
New detector studies under way – initially for √s=1.5 TeV.
Initial shielding configuration exists
Reliable MARS simulations exist (NEW: can now simulate decays from 1012 muons with ~ weight 1 “events” !)
Initial detector studies beginning
Much needs to be understood & optimized
ILC – like detector with Muon Collider shielding cones
MARS map of background particle densities in detector
STEVE GEER
Accelerator Seminar SLAC March, 2011

23. Accelerator Seminar SLAC 24 March, 2011
THE BIRTH OF MAP
Oct 1, 2009 letter from Denis Kovar to FNAL Director:
“Our office believes that it is timely to mount a concerted national R&D program that addresses the technical challenges and feasibility issues relevant to the capabilities needed for future Neutrino Factory and multi-TeV Muon Collider facilities. ...”
Letter requested a new organization for a national Muon Collider & Neutrino Factory R&D program, hosted at FNAL.
Muon Accelerator Program organization is now in place & functioning: >200 participants from 15 institutions:
ANL, BNL, FNAL, JLab, LBNL, ORNL, SLAC, Cornell, IIT, Princeton, UCB, UCLA, UCR, U-Miss, U. Chicago
MAP R&D proposal reviewed August 2010 … committee concluded that the “proposed work was very important to the field of high energy physics.”
STEVE GEER
Accelerator Seminar SLAC March, 2011

24. Accelerator Seminar SLAC 24 March, 2011
MAP MISSION STATEMENT
The mission of the Muon Accelerator Program (MAP) is to develop and demonstrate the concepts and critical technologies required to produce, capture, condition, accelerate, and store intense beams of muons for Muon Colliders and Neutrino Factories. The goal of MAP is to deliver results that will permit the high-energy physics community to make an informed choice of the optimal path to a high-energy lepton collider and/or a next-generation neutrino beam facility. Coordination with the parallel Muon Collider Physics and Detector Study and with the International Design Study of a Neutrino Factory will ensure MAP responsiveness to physics requirements.
STEVE GEER
Accelerator Seminar SLAC March, 2011

25. Accelerator Seminar SLAC 24 March, 2011
MAP ORGANIZATION
“”Level 0”
“Level 1”
STEVE GEER
Accelerator Seminar SLAC March, 2011

26. Accelerator Seminar SLAC 24 March, 2011
ORGANIZATION: L1 & L2
“Level 1”
L2 assignments
- FNAL; 4½ people
- Other Labs: 3 people
- Universities: 3½ people
- SBIR Companies: 1 person
STEVE GEER
Accelerator Seminar SLAC March, 2011

27. PROPOSED MAP PLAN / DELIVERABLES
Deliver on our commitments to making MICE and the IDS-NF studies a success.
Deliver a Design Study to enable the community to judge the feasibility of a multi-TeV Muon Collider (~FY16):
(i) an end-to-end simulation of a MC complex based on technologies in-hand or that can be developed with a specified R&D program.
(ii) hardware R&D and experimental tests to guide & validate the design work.
(iii) Rough cost range.
(iv) R&D plan for longer term activities (e.g. 6D cooling expt)
STEVE GEER
Accelerator Seminar SLAC March, 2011

28. Accelerator Seminar SLAC 24 March, 2011
TECHNICAL CHALLENGES
There has been much progress over the last decade, but there remains many technically challenging issues that must be addressed before a Muon Collider can be built:
High field solenoids operating close to the target (4MW beam)
RF operation in magnetic fields
The last few stages of the cooling channel
Cost effective acceleration
Background mitigation & understanding detector performance
STEVE GEER
Accelerator Seminar SLAC March, 2011

29. TECHNICAL CHALLENGES Target Solenoids
For a MW-class proton beams
How radiation hard can we make the solenoids?
What thermal loads can we manage?
Need R&D to establish the limitations & build confidence in our target station designs
Conductor radiation tests
Radiation damage simulations & verification
Target station radiation simulations (MARS)
Thermal management studies?
Model magnet radiation tests
20T Target Solenoid
STEVE GEER
Accelerator Seminar SLAC March, 2011

30. TECHNICAL CHALLENGES NCRF in Magnetic Fields
Significant degradation in maximum stable operating gradient for NCRF copper cavities in few Tesla coaxial field
805 MHz
Mucool Test Area
Ongoing R&D program to maximize gradient in B field:
(i) high pressure gas filled cavities, (ii) Be cavities, (iii) ALD, (iv) magnetic insulation
STEVE GEER
Accelerator Seminar SLAC March, 2011

31. TECHNICAL CHALLENGES High Field Solenoids
At the end of cooling channel want very high field (~30T) solenoids
On going national R&D to develop very high field HTS solenoids.
Great promise but many challenges:
Conductor performance
Quench protection
stresses
PBL (SBIR) 35T design
NHMFL YBCO Test Coil (27T – DB = 7T)
FNAL TD test cable. Test degradation of Jc in cabling process
STEVE GEER
Accelerator Seminar SLAC March, 2011

32. IMPACT OF MUON COLLIDER DESIGN FEASIBILITY STUDY
NOW 1 2 3 4 5 6 7
PROPOSED MC-DFS
MUON COLLIDER PROPOSAL
7. System Prototype
6. Sub-System Beam Tests
5. Semi-realistic sub-systems
4. Early sub-system Bench Tests
3. Component R&D
2. Technical Concept
1. Basic Idea
Ring
6D Cooling
Target & Dump
Bunch / Phase
Initial Cooling
Final Cooling
Acceleration
Pre-Acceleration
Based on NASA Technology Readiness Levels
STEVE GEER
Accelerator Seminar SLAC March, 2011

33. Accelerator Seminar SLAC 24 March, 2011
PAST-PRESENT-FUTURE
First
~10 years
FY07 –
FY09
FY10
NOW
≥FY11
MAP
Interim
MAP
NFMCC +
MCTF
MAP
NFMCC
~4 M$
~9 M$
~10 M$
~15 M$ (requested)
STEVE GEER
Accelerator Seminar SLAC March, 2011

34. INFORMING THE COMMUNITY
STEVE GEER
Accelerator Seminar SLAC March, 2011

35. Accelerator Seminar SLAC 24 March, 2011
FINAL REMARKS
MAP is up and running:
MAP Management plan signed by DOE-OHEP
MAP Director search is under way (
There is a real chance to show, within ~6 years, that a multi-TeV Muon Collider is feasible with an estimated cost range, and to specify the remaining R&D needed.
The proposed plan requires ~15M$/yr (FY10 dollars)
Many challenges, but we believe we can succeed
STEVE GEER
Accelerator Seminar SLAC March, 2011

36. A VISION START WITH PROJECT X 2 MW (60-120 GeV) 1300 km Neutrinos
Muons
Kaons
Nuclei
“simultaneously”
2 MW ( GeV)
1300 km
2 MW at ~3 GeV
flexible time structure
and pulse intensities
STEVE GEER
Accelerator Seminar SLAC March, 2011

37. Accelerator Seminar SLAC 24 March, 2011
A VISION
ADD NEUTRINO
FACTORY
Enhanced Neutrinos
Enhanced Muons
Muon Collider test bed
Kaons
Nuclei
“simultaneously”
4MW protons
5 GeV muons
1300 km
STEVE GEER
Accelerator Seminar SLAC March, 2011

38. Accelerator Seminar SLAC 24 March, 2011
A VISION
ADD MUON COLLIDER m+ m-
4 TeV Collider
STEVE GEER
Accelerator Seminar SLAC March, 2011