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Advanced Accelerators for Future Particle Physics and Light Sources. J. B. Rosenzweig UCLA Department of Physics and Astronomy AAAS Annual Meeting Chicago, February 13, 2009. Introduction. Accelerators have been central tools in science for three-fourths of a century
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Advanced Accelerators for Future Particle Physics and Light Sources J. B. Rosenzweig UCLA Department of Physics and Astronomy AAAS Annual Meeting Chicago, February 13, 2009
Introduction • Accelerators have been central tools in science for three-fourths of a century • Enables research both fundamental and essential • HEP colliders: structure of matter at basic level • Light sources: structure of matter at functional level • Modern accelerators have extreme sophistication • Performance optimized over decades • New ideas in context of mature technologies • Accelerator science is a victim of its own success • Demand for frontier capabilities met at … • Size and cost at limit of realizability, public support
Medicine Light sources (3rd Generation) Nuclear physics X-ray FEL Historical schematic of accelerators: Particle physics leads, spin-offs follow quickly Betatron FFAG, etc. Superconducting Circular Collider Circular Collider Synchrotron VLHC? Cyclotron Muon Collider? 2030 1930 Ion Linear Accelerators Ultra-High Energy LC? Electrostatic Accelerators Electron Linear Accelerators Electron Linear Colliders Laser/Plasma Accelerators? AAAS 2009
Colliders and the energy frontier • Colliders uniquely explore energy (U) frontier • Exp’l growth in equivalent beam energy w/time • Livingston plot: “Moore’s Law” for accelerators • We have long been falling off plot • Challenge in energy, but not only…luminosity (high beam quality, density) as well • How to proceed? • Mature present techniques, or… • Discover new approaches
Tevatron complex at FNAL (linacs, rings, buffalo…) 27 km circumference Limitations on collider energy • Synchrotron radiation power loss • Forces future e+-e- colliders to be linear • Large(!) circular machines for heavier particles • Consider muons for lepton colliders? • Scaling in size/cost • Near unitary limits • Few 104 m in dimension • Few $/€ 109
The energy challenge • Avoid giantism • Cost above all • Higher fields give physics challenges • Circular machines: magnets • Linear machines: high field acceleration • Enter new world of high energy density physics • Beam density, energy • Beam quality must increase to compensate smaller cross-section • Stored field energy High energy densty in action at the LHC
Linear accelerator schematic High energy density in future e- linear accelerators • High fields give violent accelerating systems • Relativistic e- oscillations • Diseases • Breakdown, dark current • Peak/stored energy • Power dissipation • Approaches • High frequency, normal cond. • Superconducting (many apps) • Laser-fed optical structures? • Laser = high peak power • Miniaturization… TESLA SC cavity
Cryostat with 16 T Nb3Sn magnet at LBNL Muon collider schematic (R. Johnson) Approaches to new collider paradigms • Advancement of existing techniques • Higher field (SC) magnets (VLHC) • Use of more exotic colliding particles (muons) • Higher gradient RF cavities (X-band LC) • Superconducting RF cavities (TESLA LC) • Revolutionary new approaches (high gradient frontier) • New sources: i.e.lasers • New accelerating media: i.e.plasmas • Truly immersed inhigh energy density physics Another Talk
10-15 GeV electrons ~1 Å radiation HEP Spin-offf: X-ray SASE FEL based on SC RF linear accelerator • Synchrotron radiation is again converted from vice to virtue: SASE FEL • Coherent X-rays from multi-GeV e- beam • Unprecedented brightness • Cavities spin-off of TESLA program • Alslo high brightness e- beam physics • Beginning now • High average beam power than warm technologies (e.g. LCLS at Stanford) • ManySASE FEL projects worldwide 10 orders of magnitude beyond 3rd gen X-ray light source!
The optical accelerator • Scale the linac from 1-10 cm to 1-10 mm laser! • Scale beam sizes • Resonant linac-like structure • Slab symmetry • Take advantage of copious power • Allow high beam charge • Suppress wakefields • Limit on gradient? • 1-2 GV/m, avalanche ionization • Experiments • ongoing at SLAC (1 mm) • planned at UCLA (340 mm) Resonant dielectric structure schematic e-beam Simulated field profile (OOPIC); half structure FNAL Colloquium Laser power input
Inverse Cerenkov Acceleration • Coherent Cerenkov wakes can be extremely strong • Short beam, small aperture; miniaturization… • SLAC FFTB, Nb=3E10, sz= 20 mm, a=50 mm, > 11 GV/m • Breakdown observed above 5.5 GV/m(!); on to plasma Simulated GV/m Cerenkov wakes for typical FFTB parameters (OOPIC)
Past the breakdown limit:Plasma Accelerators • Very high energy density laser or e- beam excites plasma waves as it propagates • Extremely high fields possible: Schematic of laser wakefield Accelerator (LWFA) Ex: tenous gas density AAAS 2009
Plasma Wakefield Acceleration (PWFA) • Electron beam shock-excites plasma • Same scaling as Cerenkov wakes, maximum field scales in strength as • In “blowout” regime, plasma e-’s expelled by beam. Ion focusing + EM acceleration= plasma linac AAAS 2009
Modified PRL cover • New experiments: >10 GeV in 30 cm plasma (E167) Ultra-high gradient PWFA: E164 experiment at SLAC FFTB • Uses ultra-short beam (20 m) • Beam field ionization creates dense plasma • Over 4 GeV(!) energy gain over 10 cm: 40 GV/m fields • Self-injection of plasma e- s • X-rays from betatron oscillations ne=2.5x10 17 cm-3 plasma M. Hogan, et al. AAAS 2009
PWFA doubles SLAC energy • Acceleration gradients of ~50 GV/m (3000 x SLAC) • Doubled 45 GeV beam energy in 1 m plasma • Required enormous infrastructure at SLAC • Not yet a “beam” Nature 445 741 15-Feb-2007
Future PWFA: whither FACET? • Further progress in PWFA (and dielectric) awaits FFTB replacement • FACET program addresses critical questions for PWFA • Use notch collimator to produce two bunches • Plasma acceleration with narrow energy spread • High-gradient positron acceleration
Plasma wave excitation with laser (LWFA): creation of very high quality beam • Trapped plasma electrons in LWFA give n~1 mm-mrad at Nb>1010 • Narrow energy spreads can be produced • accelerating in plasma channels • Looks like a beam! • Less expensive than photo-injector/linac/compresor… • Very popular • LBL, Imperial, Ecole Polytech.
Channel guided laser-plasma accelerator (LWFA) has produced GeV beams! • Higher power laser • Lower density, longer plasma Capillary 1 GeV e- beam 3 cm 40 TW, 37 fs W.P. Leemans et. al, Nature Physics2 (2006) 696
Laser 1000 TW 40 fs < 1 m ~10 GeV e- beam Multi-GeV beams BELLA @ LBNL 10 GeV PWFA • Two-stage design • Need 40 J in 40 fs laser pulse • BELLA Project: 1 PW, 1 Hz laser Will be followed by staging at multi-GeV energies 10 GeV beam allow positron production, XFEL!
10 GeV module: building block for a laser-plasma linear collider Electron Positron 200-500 m, 100 stages Laser 1 TeV 1 TeV 200-500 m, 100 stages 10 GeV e+ e- • Many experimental questions • Can begin to answer with ~$10-20M • BELLA is ~ head of world effort • Serious competition!
PW class laser gives multi-GeV electron beams in single stage: Table-top XFEL undulator • Beam quality needs to be controlled • Naturally gives fsec pulses! “4D imaging with atomic resolution” • Hot topic… Projects in EU, USA
ELI Relativistic Engineering Secondary Beam Sources Electrons Positron ion Muon Neutrino Neutrons X rays g rays accelerators Synchr. Xfel The Europeans think big:Extreme Light Infrastructure Exawatt Laser Fundamental Interaction Ultra-Relativistic optics Super hot plasma Nuclear Physics Astrophysics General relativity Ultra fast phenomena NLQED Attosecond optics Rel. Microelectronic Rel. Microphotonic Nuclear treatement Nuclear pharmacology Hadron therapy Radiotherapy Material science
>100PW, 1Hz ELI 10PW, 1 Hz 1PW >1Hz Multi stage accelerator Single stage accelerator Accelerator physics Fundamental physics Beam lines for users e, p, X, g, etc… synchroton & XFEL communities ELI’s strategy for accelerator physics GeV e-beam .2 GeV p-beam 10 GeV e-beam GeV p-beam 50 GeV e-beam few GeV p-beam
1017 ELI 1016 ELI 1015 1014 Laser Power (W) 1013 1012 Electron beam energy and laser power evolution? 6 10 « conventional » technology 5 10 4 10 103 Maximale Electrons Energy (MeV) *LLNL LOA *LUND RAL 102 LOA *LLNL KEK UCLA ILE ¤ 10 UCLA LULI 1 1930 1940 1950 1960 1970 1980 1990 2000 2010 Years Lasers are doing better with their Moore’s law until now...
. . . . . . ELI . . . . . . . . . . . . . . . . . . . . . . . . Towards an Integrated Scientific Project for European Researcher : ELI
Advanced Accelerators • Advanced accelerators based on exotic new techniques have gone from concept to proof of application in last decade • US HEP led way, spin-offs to light sources • World-wide competition increasing • Excitement brings in energetic young researchers… must be on the cusp of important. US needs to reinvigorate!