Muon Collider & Neutrino Factory R&D Steve Geer

fMuon Collider &

Neutrino Factory R&DSteve Geer

1. Introduction2. Ongoing “Front End” R&D3. Muon Collder Task Force R&D4. Summary

September 14, 2007 2

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Muon Collider & Neutrino Factory R&D

Muon Collider Motivation Beyond the ILC, we would like a high-luminosity multi-TeV lepton-lepton collider option

Circular (compact) multi-TeV Lepton Collider that would fit on the Fermilab site.

Very small beam energy spread enabling precise scans and width measurements Muon Colliders may have special role for precision measurements.

The Muon Collider concept is attractive because muons do not radiate as readily as electrons (m / me ~ 207):

2 TeV MCFootprint


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Challenge To produce sufficient luminosity for an interesting physics program (L ~ 1034 cm-2 s-1 at s = few TeV) requires very bright muon beams. This is challenging:

Muons produced from pion decays occupy a large longitudinal & transverse phase space. The beam must be cooled by a large factor: a longitudinal emittance reduction of about 14 & a transverse emittance reduction of about 400 6D reduction of ~14400400 = 2 106

Muons decay (0 = 2s). Beam manipulation & acceleration must be rapid.


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Muon Collider Ingredients

– Proton Driver• primary beam on target

– Target, Capture, and Decay• create ; decay into

– Bunching & Phase Rotation• reduce E of bunch

– Cooling• reduce 6D emittance

– Acceleration• 130 MeV O(1) TeV

– Storage Ring• store for ~1000 turns

2 MWProtonSource

Hg-Jet TargetDecay

Channel

Helical Cooler

Buncher

BunchMerger

RingCooler(s)

FinalCoolerPre Accel

-erator

Acceler-ation

Collider

~ 4 km


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Neutrino Factory Ingredients– Proton Driver

• primary beam on target– Target, Capture, and Decay

• create ; decay into – Bunching & Phase Rotation

• reduce E of bunch– Cooling

• reduce transverse emitt.– Acceleration

• 130 MeV 20 GeV– Storage Ring

• store for ~500 turns;long straight section

US Design schematic

2 MWProtonSource

Hg-Jet TargetDecay

Channel

Linear Cooler

Buncher

Pre Accel-erator

Acceleration

StorageRing ~ 1 km5-10

GeV

10-20GeV

1.5-5 GeV


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Common Front-End R&D

2 MWProtonSource

Hg-Jet Target

Decay Channel

Linear Cooler

Buncher

MERIT experiment at CERN

MUCOOL R&D hosted at FNAL

MICE experiment at RAL

Hg-jet target in 15T Solenoid exposedto high intensity CERN PS beam

Development & bench testing muonionization cooling channel componentsIn the MUCOOL Test Area. Also testsrf in magnetic fields needed for buncher& phase rotation.

Testing short transverse cooling channelin a single-particle muon experiment.

ALL THIS FRONT-END R&D SHOULDBE COMPLETED BY 2010-2012


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MERIT

Fermilab contributed MARS simulations (~0.2 FTE) radiation environment & positioning of particle detectors

Target chamber

15T Solenoid

Hg container

Hg-jet hydraulic system

PS Beam

Hg-jet injected in 15T solenoid & viewed with high-speed cameras.

NFMCC initiated experiment being commissioned at CERN PS now, will run October this year.


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Ionization Cooling

Cooling Channel Section

Liq. H2 Liq. H2 Liq. H2

RF RF

Muons lose energy by dE/dx in material. Re-accelerate in the longitudinal direction reduce transverse phase space. Coulomb scattering heats the beam low Z absorber. Hydrogen is best

NEED: Solenoid channelto confine beam & provide radial focussing at absorber,Absorders for dE/dx, rf cavities for re-accleration … compact lattice requires rf operating in magnetic fields.


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MUCOOL R&DMUCOOL = NFMCCsub-collaboration

MUCOOL R&D in the MUCOOL Test Area at FNAL

805 MHz 805 MHz pillbox cavitypillbox cavity

201 MHz cavity201 MHz cavity

Liquid H2 & LiH absorbers being developed, but main present focus is on rf cavity operation (805 MHz & 201 MHz) in magnetic fields

Mission is to develop & bench -test all ioniz-ation cooling channel components


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Support for MICEMuon Ionization Cooling Experiment at RAL

Single-beam ~200 MeV/c

4T spectrometer I

4T spectrometer II

TOF

Cooling cell (~10%)=5-45cm, liquid H2, RF

Final PID:TOFCalorimeter

Tests short cooling section (MUCOOL components) & our ability to simulate it.

Mult-Stage Run Plan (2008 ~2011)

Fermilab contributions:MUCOOL 201MHz cavitytests and contributionsto tracking system & beam position monitors


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Beyond the Front-EndWe anticipate the Front-End R&D will be complete2010-2012.

2 MWProtonSource

Hg-Jet TargetDecay

Channel

Helical Cooler

Buncher

BunchMerger

RingCooler(s)

FinalCoolerPre Accel

-erator

Acceler-ation

Collider

~ 4 km

At this time we will havethe technical know-how to build a Neutrino Factory.

On the same timescale we would like to know if a Muon Collider is practical

Requires additional R&Don 6D cooling channel, acceleration & Collider Ring.


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Muon Collider Task Force

Strategy:

In July 2006, FNAL Director requested a Task Force aimed at technologies needed for a Muon Collider

Strengthen accelerator R&D activities hosted at FNALFocus on critical R&D needing enhanced supportComplement ongoing R&D pursued by NFMCCCollaborate closely with NFMCC and Muons Inc.

GOAL:Develop designs and technologies so that, within a few years (by ~2012) the community will know whether Muon Colliders are a realistic option for the future, & have a plan & timeline for the remaining R&D


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MCTF ScopeIn October 2006 MCTF submitted initial R&D plan:

Focus on Collider Ring design & cooling channeldevelopment

Proposed to start with2.8M$/year M&S

Ramp up to 5M$/yr M&S


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MCTF Activities

Muon Collider Design and Simulations to establish the required cooling parameters.

Component Development Helical Magnets HTS High-Field Solenoids Pressurized rf Cavities

Beam tests High Pressure Cavity tests 6D Cooling Channel Experiment

See Andreas Jansson’stalk for details

Muon ColliderCooling channelcomponent R&D


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High- or Low-Emittance ?High-Emittance Strategy (pursued by MCTF + NFMCC)Package muons into 1 bunch/sign/cycle with numbermuons limited by beam-beam tune shift.

Low-Emittance Strategy (pursued by MCTF + Muons Inc)Lower number muons/bunch with many bunches/ cycle lower transverse emittance at beam-beam tune shift limit.

Pros & Cons:Collider ring design for high-emit. case exists … low emit. ring design harder. Additional technologies neededfor low emit., but may yield higher luminosity.In both cases we may be able to use ILC cavities !


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Cooling Channel SimulationsSimulations exists forall high-emit. cooling channel pieces. Not all matching simulated.

Requires “Guggenheim” channel, rebuncher, & HTS solenoids atend.

First part of low-emit. cooling channel also simulated. Requires “Helical Magnets”,& high-pressure rf cavities.Last part of channel requires development of concepts (e.g. “Parametric Ionization Cooling”)


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Goals & Support …

MCTF FY07 and 08 activities focused on: (i) Determining which 6D cooling channel technologies are viable (ii) Determining which Collider design strategies (low- and/or high- emittiance) are viable (iii) Preparing for 6D cooling expt proposal

FTE SWF M&S M&S+SWFFY07 16.6 3601 1080 4681FY08 11.0 2556*) 1623 4178

Front-End R&D supported in US via the NFMCC: FY07 support = 1.8M$ direct (mostly M&S) + 1.8M$ base program funding (mostly SWF) + 0.7M$ supplemental funding. NFMCC direct+base funding has been ~flat for a number of years.

*) Reduction in effort is a problem. See next slide

guideline


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Muon R&D at FNAL

FY07 16.6 1080General support (incl. travel) 106Simulations 2.0 0MTA Beamline 1.5 665MUCOOL 3.6 56MICE 7.0 186HCC 2.0 67HTS 0.5 0

FY08 11.0 1623General support (including travel) 93 Simulations 3.0 0MTA Beamline & High pressure cavity test 4.0 400MUCOOL 4.0 370MICE 0 80HCC 0 3006D Cooling Experiment 0 150HTS 0 230

FTE M&S (K$)


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Steering Group Guidance

Group 5 (Colliders beyond LHC and ILC) recommended for Muon Collider R&D in the US: “… a minimum of 20M$ annually and 100FTE appropriate skill set …”

In all scenarios … “R&D for future accelerator options concentrating on a neutrino factory and muon collider should be increased”

FY08 budget guidance is inconsistent with the recent Steering Group recommendations:


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SummaryFront-end R&D for Neutrino Factories & Muon Colliders is pursued at Fermilab in the context of the national NFMCC and their international partners.The front-end R&D is advanced (MUCOOL, MICE, MERIT), and is expected to be complete by 2010-2012.

Additional R&D is required to develop the technology for Muon Colliders, and in particular for the 6D cooling channel .The MCTF is focused on understanding the collider ring design (to establish the cooling channel goals), & developing cooling channel technologies

A reasonable Muon Collider R&D goal is, by ~2012, to (i) establish a Muon Collider is practical, (ii) advance the design and technology development to the point where the remaining required R&D can be defined and a technically limited schedule can be developed. The FY08 guidance is not consistent with this goal.


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Backup: Co-ordination

Co-ordination group meets ~ once per month

NFMCCLEADERSHIP

MCTFLEADERSHIP

MUON COLLIDER R&D CO-ORD GROUP

+

NFMCCMANAGED

MC R&DSUBACTIVITIES

MCTFMANAGED

MC R&DSUBACTIVITIES

MUONCOLLIDERR&DPROGRAM

In Spring 2007 Steve Holmes requested formation of a co-ordinationGroup to ensure overall MCTF + NFMCC Muon Collider R&D plan is coherent & effective


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Backup: Collider Parameter SetsLow Emit. High Emit. MCTF06 MCTF07

s (TeV) 1.5

Av. Luminosity (1034/cm2/s) * 2.7 1 1 1.33

Av. Bending field (T) 10 6 8.33 6

Mean radius (m) 361.4 500 363.8 500

No. of IPs 4 2 2 2

Proton Driver Rep Rate (Hz) 65 13 60 40

Beam-beam parameter/IP 0.052 0.087 0.1 0.1

* (cm) 0.5 1 3 1

Bunch length (cm) 0.5 1 2 1

No. bunches / beam 10 1 1 1

No. muons/bunch (1011) 1 20 12 11.3

Norm. Trans. Emit. (m) 2.1 25 13 12.3

Energy spread (%) 1 0.1 0.1 0.2

Norm. long. Emit. (m) 0.35 0.07 0.14 0.14

Total RF voltage (GV) at 800MHz 406.6 103c 0.21** 0.26103c 0.84**

Muon survival N/N0 1 0.07 1 0.2

+ in collision / proton 0.075*** 0.01 0.15 0.03

8 GeV proton beam power 1.1 3.2 0.6 1.9

Muon Collider & Neutrino Factory R&D Steve Geer

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