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E-164

E-164. Presented by Patrick Muggli E-162 Collaboration :. F.-J. Decker, M. J. Hogan, R. Iverson, C. O’Connell, P. Raimondi, R.H. Siemann, D. Walz Stanford Linear Accelerator Center B. Blue, C. E. Clayton, C. Huang , C. Joshi, K. A. Marsh, W. B. Mori University of California, Los Angeles

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E-164

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  1. E-164 Presented by Patrick Muggli E-162 Collaboration: F.-J. Decker, M. J. Hogan, R. Iverson, C. O’Connell, P. Raimondi, R.H. Siemann, D. Walz Stanford Linear Accelerator Center B. Blue, C. E. Clayton, C. Huang, C. Joshi, K. A. Marsh, W. B. Mori University of California, Los Angeles T. Katsouleas, S. Lee, P. Muggli University of Southern California and E-164+X: + C. Barnes, P. Emma, P. Krejcik, D. Johnson, W. Lu,E. Oz

  2. OUTLINE • Past year: -E-162, PWFA with long e-, e+ bunches: sz≈700 µm • Next year: -E-164 PWFA with short e- bunches: sz≈100 µm • 5+ years: -E-164 PWFA with ultra-short e- bunches: sz≈20 µm -Long term ideas Work supported by USDoE #DE-FG03-92ER40745, DE-AC03-76SF00515, #DE-FG03-98DP00211, #DE-FG03-92ER40727, NSF #ECS-9632735, NSF #DMS-9722121.

  3. Final Focus Test Beam 3 km e-/e+ LINAC PLASMA WAKEFIELD EXPERIMENT @ SLAC 3 km for 50 GeV e- and e+ 1 m for 1 GeV?

  4. Focusing (Er) Defocusing Decelerating (Ez) Accelerating - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + + + - - - - - - - - - + - - + + + + + - + + + + + - + + + + + + + - - - - + + + + + + + + + + + + + + + - - - - - - - - - - - electron beam - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + - - - - - + + + + + + + + + + + + - - - - + + + + + + + + + + + + + + + + + + + + + + + PLASMA WAKEFIELD (e-) • Plasma wave/wake excited by a relativistic particle bunch • Plasma e- expelled by space charge forces => energy loss, focusing (ion channel formation rc≈(nb/ne)1/2sr) • Plasma e- rush back on axis => energy gain • Linear scaling: ≈ 1/sz2 @ kpesz≈√2 • Plasma Wakefield Accelerator (PWFA) = Transformer Booster for high energy accelerator

  5. E-162: y y E-157: x x Ionizing Laser Pulse (193 nm) e-,e+ Streak Camera (1ps resolution) ∫Cdt Li Plasma ne≈21014 cm-3 L≈1.4 m Quadrupoles Bending Magnet X-Ray Diagnostic y,E y,E N=21010 sz=0.6 mm E=28.5 GeV Cherenkov Radiator Optical Transition Radiators Dump Imaging Spectrometer 25 m x x EXPERIMENTAL SET UP IP0: IP2: • Optical Transition Radiation (OTR) • CHERENKOV (aerogel) - Spatial resolution ≈100 µm - 1:1 imaging, spatial resolution <9 µm - Energy resolution≈30 MeV - Time resolution: ≈1 ps

  6. CHANNELING OF e- OTR Images ≈1m downstream from plasma Envelope equation: In an ion channel: Beam-plasma matching: Not matched • ne, matched =2.51014 cm-3 • s insensitive to ne at matching, stabilize hose instability • Channeling of the beam over 1.4 m or >12b0

  7. DYNAMIC FOCUSING WITHIN e-BUNCH • Channel Formation Head ß Dynamic Focusing Head • Correlated Energy Spread ß Space-Time Correlation after Energy Dispersion

  8.  = -3.5  = -2.8  = -2.1  = -1.4  = -3.5  = -0.7  = 0  = 0.7  = 1.4 Beam Size (m)  = 4.2  = 2.1  = 2.8  = 3.5  = 4.2 = Head = Middle = Blowout Density (x1014 cm-3) DYNAMIC FOCUSING WITHIN e-BUNCH • Different t or z bunch slices experience a different number of betatron oscillations C. O’Connell et al., PRST-AB (2002)

  9. e- Back Back Blow Out Front 3s0 beam 3s0 beam Front e+ e- & e+ BEAM NEUTRALIZATION 3-D QuickPIC simulations, plasma e- density: sr=35 µm sr=700 µm N=1.81010 d=2 mm e-: ne0=21014 cm-3, c/wp=375 µm e+: ne0=21012 cm-3, c/wp=3750 µm • Uniform focusing force (r,z) • Non-uniform focusing force (r,z)

  10. FOCUSING OF e-/e+: HIGH ne • from OTR images ≈1m from plasma exit for e-: • Focusing limited by emittance growth due to plasma focusing aberrations? M.J. Hogan et al., PRL (2003)

  11. ne=0 ne≈1014 cm-3 2mm • Ideal Plasma Lens in Blow-Out Regime e- 2mm • Plasma Lens with Aberrations e+ FOCUSING OF e-/e+ • OTR images ≈1m from plasma exit (ex≠ey)

  12. EXPECTED ENERGY LOSS/GAIN, e- 2-D OSIRIS PIC simulation: L=1.4 m, ne=1.51014 cm-3, sz=40 µm fp=110 GHz @ ne=1.51014 cm-3 • Expected energy loss: 95 MeV (average) • Expected energy gain: 260 MeV (average), 335 MeV (peak) • Expected energy gain < incoming correlated energy spread => need time discrimination

  13. ENERGY GAIN/LOSS AVERAGE, e- ps slice analysis results • Average energy loss (slice average): 159±40 MeV • Average energy gain (slice average): 156 ±40 MeV (≈3107 e-) • Events/particles to more than 250 MeV

  14. Design Charge:21010 Low Charge: 1.21010 E E Energy Spread≈1.5% x x ENERGY LOSS/GAIN LOW CHARGE, e+ Cerenkov images => energy spectrum e+- beam: E 28.5 GeV N1.21010e+ sz 0.73 mm sr 40 µm erN 1210-5 m rad Very Little Energy Spread • Lower charge allows for better time dispersed energy measurements

  15. ne=1.81014cm-3 Loss Gain Plasma Off ne=1.81014cm-3 Front Back Back Front ENERGY LOSS/GAIN LOW CHARGE e+ N=1.21010 e+ Experiment 2-D Simulation • Loss ≈ 45 MeV/m  1.4 m=63 MeV • Loss ≈ 50 MeV • Gain ≈ 75 MeV • Gain ≈ 60 MeV/m  1.4 m=84 MeV • Excellent agreement! B. Blue et al., submitted to PRL

  16. 106 43 4.3 0.2 GV/m NUMERICAL SIMULATIONS: E-164/X , e- • E-164X: sz=20-10 µm: >10 GV/m acceleration! (sr dependent!) • Plasma length, energy gain limited by FFTB dump line acceptance fp=2.8 THz, W=3MT/m @ ne=1017 cm-3

  17. Beam tuning set up Lithium plasma source E-164: RIGHT NOW! OTRs at plasma entrance/exit UV-photo-ionized plasma • Goal: >1 GeV over 30 cm (4 GeV/m) • Plasma length, energy gain limited by FFTB dump line acceptance fp≈700 GHz, W=3MT/m @ ne=51015 cm-3

  18. E-164X: BEAM-IONIZED PLASMA • Plasma source: neL limited by laser fluence and absorption • Relativistic plasma electrons=> ne > given by kpsz≈√2 ne≈1016-1017 cm-3 • Short bunch, Er≈5.210-19N/sz sr (GV/m) > tunneling field (Kyldish, ADK) N=1010 e-, sz=sr=20 µm in Cs Vapor pressure curves • Plasma density = neutral density (nf=1), easier, more stable! • Channeling+long plasma+large gradient=large energy gain!

  19. 5+ YEARS • Propagation in long field ionized plasmas, large energy gains • Stability against hose the instability • Two-bunch experiments: - wake loading (ORION) - beam quality (e, ∆E/E, ...) • ... “Pre-After-Burner”

  20. SUMMARY • E-157/162 built a PWFA laboratory for 30 GeV beams • Wealth of important results: - Beam refraction, Muggli et al., Nature 2001 - Electrons transverse dynamics, Clayton et al., PRL 2002 - High brightness X-ray emission, Wang et al., PRL2002 - Focusing dynamics, O’Connell et al., PRSTAB 2002 - Positrons dynamic focusing, Hogan et al., PRL 2003 - Acceleration of positrons, Blue et al., submitted to PRL - Acceleration of electrons, Muggli et al., in preparation •E-164: 1 GeV energy gain over 30 cm, PWFA sz scaling law • E-164X: Ultra short bunches, ultra-high gradients in field-ionized plasmas • Two-bunch experiments, hose instability, ultra-high energy gains, after-burner.

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