New Technologies for Accelerators - Advanced Accelerator Research - Bob Siemann March 19, 2003

1. New Technologies for Accelerators- Advanced Accelerator Research - Bob SiemannMarch 19, 2003 Introduction An Incomplete Survey Plasma Waves and The Afterburner A Laser Driven Linear Collider Conclusion

2. Particle Physics Discoveries • 2 n’s • J/ • W & Z • top Accelerator Innovations • Phase focusing • Klystron • Strong focusing • Colliding beams • Superconducting magnets • Superconducting RF Science  Innovation

3. 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

4. Accelerator Science & Technology • Evolution & Maturity Underlying science & technology Developing a design => parameter lists, etc Optimization Construction Commissioning & operation Advanced accelerator research = high gradient e+e- acceleration • Advanced accelerator research is one aspect of accelerator innovation

5. mm-wave accelerator fabricated by deep x-ray lithography R. Kustom et al, ANL Dielectric wakefield accelerator – Two beam experiment W. Gai et al, ANL An Incomplete Survey

6. Active medium SM-LWFA electron energy spectrum S h o t 1 2 ( 1 0 k G ) Self modulated laser wakefield acceleration E > 100 MeV, G > 100 GeV/m 6 S h o t 2 6 ( 1 0 k G ) 1 0 S h o t 2 9 ( 5 k G ) S h o t 3 3 ( 5 k G ) S h o t 3 9 ( 2 . 5 k G ) 5 1 0 S h o t 4 0 ( 2 . 5 k G ) Amplified wake 4 1 0 Relative # of electrons/MeV/Steradian A. Ting et al, NRL L. Schächter, Technion 3 1 0 Wakefield amplification by an active medium Trigger bunch 6 8 1 0 2 0 4 0 6 0 8 0 1 0 0 2 0 0 Accelerated bunch E l e c t r o n e n e r g y ( i n M e V ) An Incomplete Survey

7. Plasma Focusing of e+ beams P. Chen et al, SLAC Transport of an e- beam through a 1.4 m long plasma P. Muggli et al, USC An Incomplete Survey

8. 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 Y.-C. Huang Hansen Experimental Physics Laboratory National Tsing Hua University, Taiwan L. Schächter Technion Israeli Institute of Technology

9. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + Physical Principles of the Plasma Wakefield Accelerator • Space charge of drive beam displaces plasma electrons - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + + + - - - - - - - - - + - - + + + + + - + + + + + - + + + + + + + - - - - + + + + + + + + + + + + + + + - - - - - - - - - - - electron beam - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Ez • Plasma ions exert restoring force => Space charge oscillations • Wake Phase Velocity = Beam Velocity (like wake on a boat) • Wake amplitude

10. e- e+ Electrons and Positrons in Plasmas electron Radius Blow-out positron Radius Flow-in Z

11. The Afterburner Idea • 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 LENSES 50 GeV e- 50 GeV e+ e+WFA e-WFA IP

12. Runs 2&3, Summer 2001 e+ acceleration, e- acceleration Experimental Layout for Beam Plasma Experiments Located in the FFTB

13. E-162: Longitudinal Dynamics Part 4 Preliminary Energy Loss & Gain • Average energy loss (slice average): 159±40 MeV • Average energy gain (slice average): 156 ±40 MeV

14. Linear Accelerator Final Focusing System e+ e- Damping Ring Power Source L, ECM Particle Source An e+e- Linear Collider

15. Luminosity, Beam Power & Efficiency

16. Efficiency and Scalability of Power Sources Eric Colby 10/15/2002 Yb:KGd(WO4)2 l=1.037m Gt=112 fsec Pave=1.3 W h=28% SLAC PPM Klystron l=2.624 cm Gt=3 msec Pave=27 kW h=65% Source Efficiency [%] TUBES FEMs FELs 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).

17. Carrier Phase-Locked LasersDiddams et al “Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb”, Phys. Rev. Lett., 84 (22), p.5102, (2000).

18. Luminosity, Beam Power & Efficiency

19. Structure Efficiency q = 0, h = 0 because no charge is accelerated h = 0 because when • = 0 All the laser energy radiated away into broad band radiation h = hmax h/hmax h = 0 q/qmax

20. PBGFA Efficiency X. Lin, Phys. Rev. ST-AB, 4, 051301 (2001). The estimate of ZH ignores the other air tunnels and the frequency dependence of the dielectric constant

21. Charge Limit • There is a maximum charge/bunch based on efficiency • It is uncertain because ZH is uncertain • PBGFA: frequency dependence of e • LEAP: multiple slit interference • Multiple beam bunches/laser pulse • Required for high efficiency • PBGFA: t is already long to fill structure => make it slightly longer to accelerate multiple bunches • LEAP: t >> tmin => accelerate multiple bunches or waste energy

22. Levi Schächter 10/11/02 Concluding Remarks (But not for this talk) • 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.

23. A Parameter List Beam is assumed debunched at the IP

24. Linear Accelerator Final Focusing System e+ e- Damping Ring Power Source L, ECM Particle Source An e+e- Linear Collider

25. Bunching & Phase Control At l = 10 mm STELLA (Staged Electron Laser Acceleration) experiment at the BNL ATF Source: W. Kimura, I. Ben-Zvi.

26. Particle Source 10 MW @ 500 GeV 1.251014 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 l Low energy for low eI and to have IFEL bunching Do not know how to extract! Continuous injection

27. Advanced Accel. R&D Science  Innovation