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

Science Innovation

Particle Physics Discoveries

• 2 ’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 & MaturityUnderlying 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

An Incomplete Survey

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 8 10 20 40 60 80100 200

103

104

105

106

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)

Re

lativ

e #

of

ele

ctro

ns/

Me

V/S

tera

dia

n

Electron energy (in MeV)

SM-LWFA electron energy spectrum

Self modulated laser wakefield acceleration

E > 100 MeV, G > 100 GeV/m

A. Ting et al, NRL

Active medium

Trigger bunch

Amplified wake

Accelerated bunch

Wakefield amplification by an

active medium

L. Schächter, Technion

An Incomplete Survey

Plasma Focusing of e+ beams

P. Chen et al, SLAC

0

50

100

150

200

250

300

-2 0 2 4 6 8 10 12

05160cedFit.2.graph

X

DS

OT

R (µ

m)

K*Lne1/2

0 uv Pellicle

=43 µm

N

=910-5 (m rad)

0=1.15m

Transport of an e- beam through a 1.4 m long

plasma

P. Muggli et al, USC

Advanced Accelerator Physics at SLACAdvanced Accelerator Physics at SLAC

T. Katsouleas, S. Deng, S. Lee, P. Muggli, E. OzUniversity 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

UCLA

Beam-Driven Plasma Acceleration: E-157, E-162, E-164, E-164X

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. WisdomStanford University

T. I. Smith, R. L. Swent Y.-C. Huang Hansen Experimental Physics Laboratory National Tsing Hua University, Taiwan

L. SchächterTechnion Israeli Institute of Technology

Vacuum Laser Acceleration: LEAP, E-163

Physical Principles of the PlasmaPhysical Principles of the Plasma Wakefield Accelerator Wakefield Accelerator

• Space charge of drive beam displaces plasma electrons

• Wake Phase Velocity = Beam Velocity (like wake on a boat)

• Plasma ions exert restoring force => Space charge oscillations

• Wake amplitude Nb z2

( for 4z p 1

no

)

++++++++++++++ ++++++++++++++++

----- --- ----------------

--------------

--------- ----

--- -------------------- - --

---- - -- ---

------ -

- -- ---- - - - - - ------ - -

- - - - --- --

- -- - - - - -

---- - ----

------

electron beam

+ + + + + + + + + + ++ + + + + + + + + + + + + + ++ + + + + + + + + + + + + + +

+ + + + + + + + + + + + + + +-

- --

--- --

EzEz

Z

Rad

ius

electron

positron

Flow-in

Blow-out

e+

e-

Rad

ius

Electrons and Positrons in Plasmas

� 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

50 GeV50 GeV ee--

50 GeV50 GeV e e++e-WFA e+WFA

IP

LENSES

The Afterburner IdeaThe Afterburner Idea

Located in the FFTB

Experimental Layout for Beam Plasma Experiments

Runs 2&3, Summer 2001e+ acceleration, e- acceleration

-200

-150

-100

-50

0

50

100

150

200

-6 -4 -2 0 2 4 6 8

SliceEnergyGain.graphn

e=1.31014 (cm-3)

ne=1.61014 (cm-3)

ne=2.01014 (cm-3)

ne=(2.3±0.1)1014 (cm-3)

Rel

ativ

e E

nerg

y (M

eV)

(ps)

+z

+2z

+3z

-2z

-z

• Average energy loss (slice average): 159±40 MeV• Average energy gain (slice average): 156 ±40 MeV

E-162: Longitudinal Dynamics Part 4Preliminary Energy Loss & Gain

An e+e- Linear Collider

L, ECM

e+ e-Damping Ring

Power Source

Final Focusing SystemLinear Accelerator

Particle Source

Luminosity, Beam Power & Efficiency

214 c

x y

NL f

2b cP Nf mc

bL P

particles per bunch

, transverse beam sizes

collision frequency

single beam power

energy in units of rest energy

x y

c

b

N

f

P

2AC

b accelerating stpowe ructr s urource eP

P efficiency

Efficiency and Scalability of Power Sources

TUBES FEMs FELs LASERS(RF Compression, modulator losses not included)

Yb:KGd(WO4)2

=1.037t=112 fsecPave=1.3 W=28%

SLAC PPM Klystron=2.624 cmt=3 secPave=27 kW=65%

Source Frequency [GHz]

Sou

rce

Eff

icie

ncy

[%]

Carrier Phase-Lock of a Laser

M. Bellini, T Hansch, Optics Letters, 25 (14), p.1049, (2000).

Eric Colby10/15/2002

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

214 c

x y

NL f

2b cP Nf mc

bL P

particles per bunch

, transverse beam sizes

collision frequency

single beam power

energy in units of rest energy

x y

c

b

N

f

P

2acceleratinAC

b power sou g structurerceP

P efficiency

Structure Efficiency 2Cbeam H

laser

PZU qL qcZU P

q = 0, because no charge is accelerated

C

H

PZq

cZ

because 0 , 0wakeG G G

0G G

max 4C

H

ZLc Z

when max 2C

H

PZq q

cZ

= 0

= max

= 0All the laser energy radiated away into broad band radiation

q/qmax

/max

PBGFA Efficiency max 4 1g C

H g

Z

Z

max 2C

H

PZq q

cZ

X. Lin, Phys. Rev. ST-AB, 4, 051301 (2001).

19.5CZ

0 20

1130

2 /HZ Z

r

0 0.678 radius of beam tunnelr

The estimate of ZH ignores the other air tunnels and the frequency dependence of the dielectric constant

4max

0

max

10.4 6.5 10 '

30

40 sec

0. /

5.2%

77

q f

P kW

p

G GeV

e s

m

C

max

4 5

2

10 10 '

C

H

PZq q

cZ

e s

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

Concluding Remarks Recycling (M. Tigner). All laser based schemes rely on the fact that a relatively

small fraction of the energy stored in the laser cavityenergy stored in the laser cavity is extracted and used in the acceleration structureacceleration structure. Conceptually, it seems possible to take advantage of the high intensity electromagnetic field that develops in the cavity and incorporate incorporate the acceleration structure in the laser cavitythe 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. 1.06m).

The amount of energy transferred to the electrons or lost in the circuit is compensated by the active mediumcompensated by the active medium that amplifies the narrow band wakenarrow band wake generated by the macro-bunch.

Acceleration Structure

Acceleration Structure

Active Medium

Active Medium

Acceleration Structure

Active Medium

Active Medium

Acceleration Structure

Levi Schächter10/11/02

(But not for this talk)

A Parameter List

ECM = 500 GeV Laser JLC/NLC N 5106 9.5109 fc 50MHz 11.4kHz Pb (MW) 10 4.5

x/y (nm) 0.5/0.5 330/5 N 0.22 1.1

z (m) 120 300

z/c (psec) 0.4 1 0.045 0.11 L 11034 5.11033

Beam is assumed debunched at the

IP

An e+e- Linear Collider

L, ECM

e+ e-Damping Ring

Power Source

Final Focusing SystemLinear Accelerator

Particle Source

STELLA (Staged Electron Laser Acceleration) experiment at the BNL ATF

 C O 2 la se r be a m

E L E C T R O NS P E C T R O M E T E R

IF E LA C C E L E R ATO R IF E L

B U N C H E R

4 6 M e V 0 .5 n C 2 m m m ra d 3 .5 p s

0 .6 G W , 1 80 p s

Steeringcoil

BPM

BPM

BPM

BPM

Focusingquadrupo les

S teeringcoil

Focusingquadrupo les

Source: W. Kimura, I. Ben-Zvi.

Bunching & Phase ControlAt = 10 m

Particle Source

10 MW @ 500 GeV 1.251014 particles/second106 – 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

Continuous injection

Low energy for low I and to have IFEL bunchingDo not know how to extract!

Science Innovation

Advanced Accel. R&D