Transcript Document
New Technologies for Accelerators - Advanced Accelerator Research Bob Siemann March 19, 2003 • Introduction • An Incomplete Survey • Plasma Waves and The Afterburner • A Laser Driven Linear Collider • Conclusion Science Innovation Particle Physics Discoveries • 2 n’s • J/ •W&Z • top Accelerator Innovations • Phase focusing • Klystron • Strong focusing • Colliding beams • Superconducting magnets • Superconducting RF Innovation is Critical The Livingston Curve • Captures our history • Expresses our aspirations • But there is no guarantee • Approaches that have become too big, too expensive, … have been supplanted - Vital for advancing science Accelerator Science & Technology • Evolution & Maturity Underlying science & technology Developing a design => parameter lists, etc Optimization Construction Commissioning & operation • Advanced accelerator research = high gradient e+eacceleration Advanced accelerator research is one aspect of accelerator innovation An Incomplete Survey mm-wave accelerator fabricated by deep x-ray lithography Dielectric wakefield accelerator – Two beam experiment R. Kustom et al, ANL W. Gai et al, ANL An Incomplete Survey L. Schächter, Technion Active medium Wakefield amplification by an active medium Amplified wake Trigger bunch Self modulated laser wakefield acceleration E > 100 MeV, G > 100 GeV/m A. Ting et al, NRL Relative # of electrons/MeV/Steradian Accelerated bunch SM-LWFA electron energy spectrum Shot 12 (10 kG) Shot 26 (10 kG) Shot 29 (5 kG) Shot 33 (5 kG) Shot 39 (2.5 kG) Shot 40 (2.5 kG) 6 10 105 104 103 6 8 10 20 40 60 80100 Electron energy (in MeV) 200 An Incomplete Survey Plasma Focusing of e+ beams P. Chen et al, SLAC 300 0 uv Pellicle =43 µm e- Transport of an beam through a 1.4 m long plasma X DS OTR (µm) 250 =910-5 (m rad) N 0=1.15m 200 150 100 50 P. Muggli et al, USC 0 0 51 60 cedFit.2 .g ra ph -2 0 2 4 6 K*Lne1/2 8 10 12 UCLA Advanced Accelerator Physics at SLAC Beam-Driven Plasma Acceleration: E-157, E-162, E-164, E-164X T. Katsouleas, S. Deng, S. Lee, P. Muggli, E. Oz University of Southern California B. Blue, C. E. Clayton, V. Decyk, C. Huang, D. Johnson, C. Joshi, J.-N. Leboeuf, K. A. Marsh, W. B. Mori, C. Ren, J. Rosenzweig, F. Tsung, S. Wang University of California, Los Angeles R. Assmann, C. D. Barnes, F.-J. Decker, P. Emma, M. J. Hogan, R. Iverson, P. Krejcik, C. O’Connell, P. Raimondi, R.H. Siemann, D. R. Walz Stanford Linear Accelerator Center Vacuum Laser Acceleration: LEAP, E-163 C. D. Barnes, E. R. Colby, B. M. Cowan, M. Javanmard, R. J. Noble, D. T. Palmer, C. Sears, R. H. Siemann, J. E. Spencer, D. R. Walz Stanford Linear Accelerator Center R. L. Byer, T. Plettner, J. A. Wisdom Stanford University T. I. Smith, R. L. Swent Hansen Experimental Physics Laboratory Y.-C. Huang National Tsing Hua University, Taiwan L. Schächter Technion Israeli Institute of Technology Physical Principles of the Plasma Wakefield Accelerator • Space charge of drive beam displaces plasma electrons -- -- -- ----- -----+----+- + + + + + + -+--+-- +--+----+--+ + + + + + + + + -+--+- +--+--+---+- + + + +-+- +++ +++ ++ ++++ +-++-+----+--+- ++++ ++++++++++ +++--+--+++ ++++ ++++ ++ ---- ------- --- -- -- - - - -- -- - ---- -- - - - - -- --Ez • Plasma ions exert restoring force => Space charge oscillations • Wake Phase Velocity = Beam Velocity (like wake on a boat) 1 2 ( for 4 ) z p • Wake amplitude N b z no Electrons and Positrons in Plasmas Radius electron eBlow-out Radius positron e+ Flow-in Z The Afterburner Idea � � � � 50 GeV Double the energy of Collider w/ short plasma sections before IP 1st half of beam excites wake --decelerates to 0 2nd half of beams rides wake--accelerates to 2 x Eo Make up for Luminosity decrease N2/2 by halving in a final plasma lens e- LENSES e+WFA e-WFA IP 50 GeV e+ Experimental Layout for Beam Plasma Experiments Located in the FFTB Runs 2&3, Summer 2001 e+ acceleration, e- acceleration E-162: Longitudinal Dynamics Part 4 Preliminary Energy Loss & Gain ne=1.31014 (cm -3) Relative Energy (MeV) 200 SliceEnergy Gain.g ra ph ne=1.61014 (cm -3) 150 ne=2.01014 (cm -3) 100 ne=(2.3±0.1)1014 (cm -3) 50 0 -50 -100 -150 -200 -6 -2z -z -4 -2 +z +2z 2 4 0 +3z 6 8 (ps) • Average energy loss (slice average): 159±40 MeV • Average energy gain (slice average): 156 ±40 MeV An e+e- Linear Collider Linear Accelerator e+ Power Source Final Focusing System e- Damping Ring L, ECM Particle Source Luminosity, Beam Power & Efficiency 1 N2 L fc 4 x y N particles per bunch x , y transverse beam sizes Pb Nfc mc 2 L Pb Pb power sourceaccelerating structure f c collision frequency Pb single beam power energy in units of rest energy PAC 2 efficiency Source Efficiency [%] Efficiency and Scalability of Power Sources Yb:KGd(WO4)2 =1.037m Gt=112 fsec Pave=1.3 W =28% SLAC PPM Klystron =2.624 cm Gt=3 msec Pave=27 kW =65% TUBES FEMs FELs Eric Colby 10/15/2002 LASERS (RF Compression, modulator losses not included) Carrier Phase-Lock of a Laser Source Frequency [GHz] M. Bellini, T Hansch, Optics Letters, 25 (14), p.1049, (2000). Carrier Phase-Locked Lasers Diddams et al “Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb”, Phys. Rev. Lett., 84 (22), p.5102, (2000). Luminosity, Beam Power & Efficiency 1 N2 L fc 4 x y N particles per bunch x , y transverse beam sizes Pb Nfc mc 2 L Pb Pb power sourceaccelerating structure f c collision frequency Pb single beam power energy in units of rest energy PAC 2 efficiency Structure Efficiency U beam qL PZ C qcZ H 2 U laser P q = 0, 0because no charge is accelerated G G0 PZC q cZ H max 0because Gwake G0 , G 0 L ZC 4 c Z H /max =0 when = max q/qmax q qmax PZC 2cZ H = 0 All the laser energy radiated away into broad band radiation max PBGFA Efficiency q qmax X. Lin, Phys. Rev. ST-AB, 4, 051301 (2001). Z C 19.5 Z H Z0 1 130 2 r0 / r0 0.678 radius of beam tunnel 2 g ZC 4Z H 1 g PZC 2cZ H P 30kW 40 p sec G0 0.77GeV / m qmax 10.4 fC 6.5 104 e ' s max 5.2% The estimate of ZH ignores the other air tunnels and the frequency dependence of the dielectric constant Charge Limit 1. There is a maximum charge/bunch based on efficiency 2. It is uncertain because ZH is uncertain • PBGFA: frequency dependence of • LEAP: multiple slit interference 3. Multiple beam bunches/laser pulse • Required for high efficiency • PBGFA: is already long to fill structure => make it slightly longer to accelerate multiple bunches • LEAP: >> min => accelerate multiple bunches or waste energy q qmax PZ C 2cZ H 104 105 e ' s Concluding Remarks (But not for this talk) Levi Schächter 10/11/02 Recycling (M. Tigner). All laser based schemes rely on the fact that a relatively small fraction of the energy stored in the laser cavity is extracted and used in the acceleration structure. Conceptually, it seems possible to take advantage of the high intensity electromagnetic field that develops in the cavity and incorporate the acceleration structure in the laser cavity. According to estimates, the rep-rate of each macro-bunch is 1GHz and each macro-bunch is modulated at the resonant frequency of the medium (e.g. 1.06mm). The amount of energy transferred to the electrons or lost in the circuit is compensated by the active medium that amplifies the narrow band wake generated by the macro-bunch. A Parameter List Beam is assumed debunched at the IP ECM = 500 GeV N fc Pb (MW) x/y (nm) N z (mm) z/c (psec) L Laser 5106 50MHz 10 0.5/0.5 0.22 120 0.4 0.045 11034 JLC/NLC 9.5109 11.4kHz 4.5 330/5 1.1 300 1 0.11 5.11033 An e+e- Linear Collider Linear Accelerator e+ Power Source Final Focusing System e- Damping Ring L, ECM Particle Source Bunching & Phase Control At = 10 mm STELLA (Staged Electron Laser Acceleration) experiment at the BNL ATF IF E L A C C E L E R A T O R IF E L B U N C H E RB P B P M E L E C T R O N S P E C T R O M E T E R B P M F o c u s n i g q u a d u rp o e ls S e t e n i r g c o l i Source: W. Kimura, I. Ben-Zvi. B P M Particle Source 10 MW @ 500 GeV 1.251014 particles/second 106 – 107/ 1 psec long bunch spaced at 50 MHz ~100 optically spaced bunches in the 1 psec bunch Bunches spaced at harmonic of 50 MHz IFEL to bunch and accelerate at Low energy for low I and to have IFEL bunching Do not know how to extract! Continuous injection Science Innovation Advanced Accel. R&D