International Committee for Future Accelerators Sponsored by the Particles and Fields Commission of IUPAP Beam Dynamics Newsletter No. 55 Issue Editor: M. A. Palmer Editor in Chief: W. Chou August 2011 3 Contents 1 FOREWORD ............................................................................................................. 9 1.1 FROM THE CHAIRMAN ............................................................................................... 9 1.2 FROM THE EDITOR .................................................................................................. 10 2 MUON COLLIDER AND NEUTRINO FACTORY OVERVIEW ................... 12 2.1 TOWARDS A MUON COLLIDER ................................................................................ 12 2.1.1 Physics Landscape ........................................................................................ 12 2.1.2 Neutrino Factory ........................................................................................... 13 2.1.3 Muon Collider Physics ................................................................................. 15 2.1.3.1 Basics.............................................................................................. 15 2.1.3.1.1 Pair Production ............................................................... 15 2.1.3.1.2 Resonances ..................................................................... 15 2.1.3.1.3 Fusion Processes ............................................................ 16 2.1.3.2 Standard Model Higgs Bosons ....................................................... 17 2.1.3.3 Extended Higgs Sector ................................................................... 18 2.1.3.4 Supersymmetry ............................................................................... 18 2.1.3.5 New Strong Dynamics .................................................................... 19 2.1.3.6 Contact Interactions ....................................................................... 20 2.1.3.7 Extra Dimensions ........................................................................... 20 2.1.4 Summary ....................................................................................................... 21 2.1.5 Acknowledgments ........................................................................................ 21 2.1.6 References .................................................................................................... 21 2.2 AN OVERVIEW OF MUON COLLIDERS ..................................................................... 22 2.2.1 Introduction .................................................................................................. 22 2.2.2 Neutrino Factory ........................................................................................... 25 2.2.3 Proton Driver ................................................................................................ 25 2.2.4 Target … ....................................................................................................... 26 2.2.5 Phase Rotation .............................................................................................. 27 2.2.6 Charge Separation ........................................................................................ 28 2.2.7 Introduction to Transverse Ionization Cooling ............................................. 29 2.2.8 Six-dimensional Cooling Before Merge ....................................................... 30 2.2.8.1 Introduction .................................................................................... 30 2.2.8.2 RFOFO Guggenheim ..................................................................... 31 2.2.8.3 Helical Cooling Channel (HCC) .................................................... 32 2.2.8.4 Helical FOFO Snake ...................................................................... 32 2.2.8.5 Choice of 6D Cooling Method........................................................ 32 2.2.9 Merge … ....................................................................................................... 33 2.2.9.1 Introduction .................................................................................... 33 2.2.9.2 Simple Longitudinal Merge ............................................................ 33 2.2.9.3 6D Merge ........................................................................................ 34 4 2.2.10 Six-Dimensional Cooling After Merge ......................................................35 2.2.11 Final Transverse Cooling ...........................................................................35 2.2.11.1 Introduction ....................................................................................35 2.2.11.2 System of Cooling in 30–50 T Solenoids ........................................36 2.2.11.3 Other Schemes for Final Cooling ...................................................39 2.2.12 Acceleration ...............................................................................................39 2.2.13 Collider Ring Lattices ................................................................................41 2.2.14 Radiation ....................................................................................................42 2.2.14.1 Introduction ....................................................................................42 2.2.14.2 Beam Collimation ...........................................................................42 2.2.14.3 Neutrino-induced Radiation ...........................................................42 2.2.15 Machine Detector Interface ........................................................................43 2.2.16 Experimental Program and Technical Challenges .....................................45 2.2.16.1 Liquid Mercury Target R&D ..........................................................45 2.2.16.2 The Ionization Cooling Experiment (MICE) ..................................45 2.2.16.3 RF Breakdown in Magnetic Fields .................................................46 2.2.16.4 High Field HTS 30-40 T Solenoids for Final Cooling ...................47 2.2.16.5 Radiation Shielding for Collider Ring Magnets .............................47 2.2.16.6 R&D on Hydrogen Absorbers ........................................................48 2.2.17 Summary Tables .........................................................................................48 2.2.17.1 Muon Transmission ........................................................................48 2.2.17.2 Wall Power Requirements ..............................................................49 2.2.17.3 Comparison with CLIC ...................................................................50 2.2.18 Conclusions ................................................................................................50 2.2.19 References ..................................................................................................52 3 ACCELERATOR R&D TOWARDS A NEUTRINO FACTORY AND MUON COLLIDER...........................................................................................................54 3.1 THE INTERNATIONAL DESIGN STUDY FOR THE NEUTRINO FACTORY ......................54 3.1.1 Introduction ...................................................................................................54 3.1.1.1 The Neutrino Factory .....................................................................55 3.1.2 Layout and Components of the Neutrino Factory Accelerator Complex .....56 3.1.2.1 Proton Driver .................................................................................57 3.1.2.2 Target..............................................................................................59 3.1.2.3 Muon Front End .............................................................................61 3.1.2.4 Acceleration ....................................................................................65 3.1.2.5 Muon Storage Rings .......................................................................68 3.1.3 The Neutrino Detectors .................................................................................69 3.1.4 The Neutrino Factory as Part of the Muon Physics Program .......................70 3.1.5 References .....................................................................................................71 3.2 THE MUON ACCELERATOR PROGRAM .....................................................................72 3.2.1 Introduction ...................................................................................................72 3.2.2 The Birth of MAP .........................................................................................73 3.2.3 MAP Mission and Goals ...............................................................................73 3.2.4 Achievements in the First Year ....................................................................74 3.2.5 A Vision for the Future .................................................................................76 3.2.6 Summary .......................................................................................................76 5 3.2.7 References .................................................................................................... 78 3.3 MACHINE-DETECTOR INTERFACE ........................................................................... 79 3.3.1 Introduction .................................................................................................. 79 3.3.2 Sources of Background and Radiation Load ...............................................