Going Beyond Current Techniques: FACET*, a springboard to the accelerator frontier of the future Patric Muggli University of Southern California muggli@usc.edu *Facilities for Accelerator Science and Experimental Test Beams
PLASMA WAKEFIELD ACCELERATOR (PWFA) 101 Two-beam, co-linear accelerator, plasma-based accelerator Defocusing Focusing (E r ) Accelerating Decelerating (E z ) --- -- -- - - - - - - - - --- - -- -------- -- -- - ---- - - - - - - - - - + + + + + + + + + + + + - - - -- - -- -- - + + + + + + + + + + + + + + + + + + + + -- + + + + + + + + + + + + + + + + + + + + + + + + + + + - -+ + + + + + + W D + + + + + + -- - - + + + + + + + - + + + + + + + + + + + + -- - -- -- ------- - --- - - - - - - - -- -- - - --- -- - -- --- - Deceleration, acceleration, focusing by plasma Accelerating field/gradient scales as n e 1/2 electron beam Typical: n e 10 16-10 17 cm -3, λ p 100 µm, E>10 GV/m High-gradient, high efficiency energy transformer
Previous work FFTB@SLAC Studied all aspects of beam-plasma interaction Nature (2007)
PWFA@FFTB Successes
Vision Advanced Accelerator Research: Beam-driven, Plasma Wakefield Acceleration (PWFA) Demonstrated Accelerating Gradient: 50 GV/m over 85 cm Energy doubling of 42 GeV e - Build single, 25 GeV stage of a (possible) multi-stage PWFA-LC FACET Vision: reduce the price of a future e - /e + linear collider to 2-4 b$ (target) by merging the high efficiency of conventional beam generation with the large accelerating gradient of the PWFA
TeV CM Energy 10 s MW Beam Power for Luminosity Positron Acceleration Conventional technology for particle generation & focusing Plasma for acceleration PWFA-LC Concept (an example) FACET Program will demonstrate most of a single stage July 7, 2008 FACET 6
FACET is a new facility to provide high-energy, high peak current e - & e + beams for a 25 GeV PWFA stage FACET FFTB < 2006 FACET FACET 12 7
FACET Beam Parameters Absolutely unique, world-class facility e - and e + beams available Energy, E 0 23 GeV # e - /e +, N >2x10 10 (>3 nc) Transverse size σ r <10 µm (at IP) Bunch length σ z 25 µm (4% E/E 0 ) 40 µm (1.5% E/E 0 ) Peak Current >38 ka Peak E-field >45 GV/m Peak B-field >150 T (or >15 MT/m) Transverse emittances 50 and 5 mm-mrad (SLC) Extreme parameters set yields unique opportunities
FACET Program and Challenges Accelerator physics: produce drive/witness bunches Energy doubling of witness bunch in 1m-long plasma Narrow energy spread of the accelerated witness bunch particle acceleration beam acceleration Beam loading of plasma wake, energy transfer efficiency Positrons in PWFA Further develop simulation tools Develop the PWFA-LC concept
Generate Two Bunches by Selectively Collimating During Bunch Compression Process Exploit Position-Time Correlation on e - bunch to create separate drive and witness bunch e - /e - or e + /e + Adjust final compression Disperse the beam in energy x ΔE/E t dp/p [%] D W dp/p [%] D W z [mm] x [mm]...selectively collimate D W 10
FACET Experiments will accelerate a discrete bunch of particles with narrow energy spread Energy Doubling in ~1m Energy Spread ~few percent, ~30% efficiency W D W W D g a i n D l o s s 11
Beam Loading & Energy Transfer Efficiency c D W c E 0 loss E 0 gain High efficiency and narrow E/E 0 while > energy doubling
Positrons Beam in Plasmas Asymmetry e - e + Injection of e + on e - wake (or laser wake!) X. Wang, PRL (2008)
Produce Drive/Witness Bunches e - /e + Sailboat chicane: Extract e - & e + from damping rings on same linac pulse Accelerate bunches to sector 20, 5cm apart Use Sailboat Chicane to put them within 100µm at entrance to plasma Large beam loading of e - wakes with high charge e + beams True injection of e + bunch in high gradient plasma wake High current e + bunches available at FACET only!!!
FACET Users Program Compton Scattering: FFTB: Other Advanced Accelerator Concept: Dielectric Loaded Accelerator (DLA) Once FACET is built it will surely attract very interesting experiments 1) C. Bula et al., Observation of nonlinear effects in compton scattering, Physical Review Letters 76(17):3116 3119 (1996). 2) T. Kotseroglou et al., Picosecond Timing of Terawatt Laser Pulses with the SLAC 46 GeV Electron Beam, Nuclear Instruments & Methods A, 383, 309 (1996). 3) D. L. Burke et al., Positron production in multiphoton light-by-light scattering Physical Review Letters 79(9):1626 1629 (1997). 4) C. Bamber et al., Studies of nonlinear QED in collisions of 46.6 GeV electrons with intense laser pulses Physical Review D 60(9):092004 (1999) Magnetism, Solid State and Fast Time-Scale Physics: 1) I. Tudosa et al., The Ultimate speed of magnetic switching in granular recording media Nature 428:831-833 (2004). 2) C. Stamm et al., Dissipation of Spin Angular Momentum in Magnetic Switching Physical Review Letters 94, 197603 (2005). 3) K. J. Gaffney et al., Observation of structural anisotropy and the onset of liquidlike motion during the nonthermal melting of InSb, Physical Review Letters 95(12):125701 (2005). 4) A. M. Lindenberg et al., Atomic-scale visualization of inertial dynamics, Science, 308:392 395 (2005). 5) A. L. Cavalieri et al., Clocking femtosecond x-rays, Physical Review Letters 94:114801 (2005). 6) D. M. Fritz et al., Femtosecond mapping of the interatomic potential of a highly excited solid, submitted to Nature (2006). FFTB attracted us Laboratory Astrophysics: 1) D. Saltzberg et al., Observation of the Askaryan effect: Coherent microwave Cherenkov emission from charge asymmetry in high-energy particle cascades Physical Review Letters 86:2802-2805 (2001). 2) P. W. Gorham et al., Accelerator measurements of the Askaryan effect in rock salt: A Roadmap toward teraton underground neutrino detectors Physical Review D 72:023002 (2005). 3) J.W. Belz et al., Measurement of pressure dependent fluorescence yield of air: Calibration factor for UHECR detectors Astroparticle Physics 25:129-139 (2006).
Conclusions Plasma-based, beam-driven accelerator or PWFA-LC FACET = first stage of a PWFA-LC FACET is a unique world class facility FACET is based on the success of the PWFA@FFTB program FACET addresses today the issues of a future plasma-based linear collider, whether particle beam- or laser-driven FACET backed by a strong simulation program FACET brings synergy between beam and plasma physicists FACET synergy and results will improve PWFA-LC concept FACET truly is a springboard to the accelerator frontier of the future If not now, then when? If not here, then where?
Thank you to the FACET (growing) team: And thank you!