Muon Collider & Neutrino Factory R&D Steve Geer

1. Muon Collider & Neutrino Factory R&D Steve Geer • Introduction • Ongoing “Front End” R&D • Muon Collder Task Force R&D • Summary

2. 2 TeV MCFootprint Muon Collider Motivation  Beyond the ILC, we would like a high-luminosity multi-TeV lepton-lepton collider option The Muon Collider concept is attractive because muons do not radiate as readily as electrons (mm / me ~ 207): • 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. Muon Collider & Neutrino Factory R&D

3. 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 ~14400400 = 2 106  Muonsdecay (t0 = 2ms). Beam manipulation & acceleration must be rapid. Muon Collider & Neutrino Factory R&D

4. 2 MWProtonSource Hg-Jet Target Decay Channel Buncher Acceler- ation Helical Cooler RingCooler(s) BunchMerger ~ 4 km Collider FinalCooler Pre Accel -erator 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 Muon Collider & Neutrino Factory R&D

5. Neutrino Factory Ingredients US Design schematic • 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 2 MWProtonSource Hg-Jet Target n Decay Channel Buncher StorageRing Linear Cooler Pre Accel -erator 10-20GeV ~ 1 km 5-10 GeV Acceleration 1.5-5 GeV Muon Collider & Neutrino Factory R&D

6. Common Front-End R&D MERIT experiment at CERN Hg-jet target in 15T Solenoid exposed to high intensity CERN PS beam 2 MWProtonSource MUCOOL R&D hosted at FNAL Development & bench testing muonionization cooling channel components In the MUCOOL Test Area. Also testsrf in magnetic fields needed for buncher& phase rotation. Hg-Jet Target Decay Channel MICE experiment at RAL Testing short transverse cooling channelin a single-particle muon experiment. Buncher Linear Cooler ALL THIS FRONT-END R&D SHOULDBE COMPLETED BY 2010-2012 Muon Collider & Neutrino Factory R&D

7. Hg-jet hydraulic system Target chamber 15T Solenoid Hg container PS Beam MERIT NFMCC initiated experiment being commissioned at CERN PS now, will run October this year. Hg-jet injected in 15T solenoid & viewed with high-speed cameras. Fermilab contributed MARS simulations (~0.2 FTE) radiation environment & positioning of particle detectors Muon Collider & Neutrino Factory R&D

8. RF RF Liq. H2 Liq. H2 Liq. H2 Cooling Channel Section Ionization Cooling 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. Muon Collider & Neutrino Factory R&D

9. MUCOOL R&D MUCOOL = NFMCCsub-collaboration 201 MHz cavity MUCOOL R&D in the MUCOOL Test Area at FNAL Mission is to develop & bench -test all ioniz- ation cooling channel components 805 MHz pillbox cavity Liquid H2 & LiH absorbers being developed, but main present focus is on rf cavity operation (805 MHz & 201 MHz) in magnetic fields Muon Collider & Neutrino Factory R&D

10. Support for MICE Muon Ionization Cooling Experiment at RAL Tests short cooling section (MUCOOL components) & our ability to simulate it. Final PID: TOF Calorimeter Fermilab contributions: MUCOOL 201MHz cavitytests and contributionsto tracking system & beam position monitors 4T spectrometer II Cooling cell (~10%) b=5-45cm, liquid H2, RF Mult-Stage Run Plan (2008  ~2011) 4T spectrometer I Single-m beam ~200 MeV/c TOF Muon Collider & Neutrino Factory R&D

11. 2 MWProtonSource Hg-Jet Target Decay Channel Buncher Acceler- ation Helical Cooler RingCooler(s) BunchMerger ~ 4 km Collider FinalCooler Pre Accel -erator Beyond the Front-End We anticipate the Front- End R&D will be complete 2010-2012. At this time we will have the 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. Muon Collider & Neutrino Factory R&D

12. Muon Collider Task Force In July 2006, FNAL Director requested a Task Force aimed at technologies needed for a Muon Collider Strategy: Strengthen accelerator R&D activities hosted at FNAL Focus on critical R&D needing enhanced support Complement ongoing R&D pursued by NFMCC Collaborate 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 Muon Collider & Neutrino Factory R&D

13. MCTF Scope In October 2006 MCTF submitted initial R&D plan: Focus on Collider Ring design & cooling channeldevelopment Proposed to start with 2.8M$/year M&S Ramp up to 5M$/yr M&S Muon Collider & Neutrino Factory R&D

14. 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 Muon Collider Cooling channel component R&D See Andreas Jansson’stalk for details Muon Collider & Neutrino Factory R&D

15. High- or Low-Emittance ? High-Emittance Strategy (pursued by MCTF + NFMCC)Package muons into 1 bunch/sign/cycle with number muons 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 ! Muon Collider & Neutrino Factory R&D

16. Cooling Channel Simulations Simulations 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”) Muon Collider & Neutrino Factory R&D

17. Goals & Support … 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. 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+SWF FY07 16.6 3601 1080 4681 FY08 11.0 2556*) 1623 4178 guideline *) Reduction in effort is a problem. See next slide Muon Collider & Neutrino Factory R&D

18. FY07 16.6 1080 General support (incl. travel) 106 Simulations 2.0 0 MTA Beamline 1.5 665 MUCOOL 3.6 56 MICE 7.0 186 HCC 2.0 67 HTS 0.5 0 FY08 11.0 1623 General support (including travel) 93 Simulations 3.0 0 MTA Beamline & High pressure cavity test 4.0 400 MUCOOL 4.0 370 MICE 0 80 HCC 0 300 6D Cooling Experiment 0 150 HTS 0 230 Muon R&D at FNAL FTE M&S (K$) Muon Collider & Neutrino Factory R&D

19. Steering Group Guidance FY08 budget guidance is inconsistent with the recent Steering Group recommendations: In all scenarios … “R&D for future accelerator options concentrating on a neutrino factory and muon collider should be increased” 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 …” Muon Collider & Neutrino Factory R&D

20. Summary Front-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. Muon Collider & Neutrino Factory R&D

21. MUON COLLIDER R&D CO-ORD GROUP NFMCCLEADERSHIP MCTFLEADERSHIP + NFMCC MANAGEDMC R&DSUBACTIVITIES MCTF MANAGED MC R&DSUBACTIVITIES MUON COLLIDER R&D PROGRAM Backup: Co-ordination In Spring 2007 Steve Holmes requested formation of a co-ordination Group to ensure overall MCTF + NFMCC Muon Collider R&D plan is coherent & effective Co-ordination group meets ~ once per month Muon Collider & Neutrino Factory R&D

22. Backup: Collider Parameter Sets Muon Collider & Neutrino Factory R&D