1. The Upgraded Argonne Wakefield Accelerator Facility (AWA)
Argonne National Laboratory:
Euclid Techlabs LLC:
Students:
W. Gai , M. Conde, S. Doran, W. Liu, J. G. Power, C. Whiteford
S. Antipov, S. Baryshev, C. Jing, J. Qiu , R. Konecny, A.Kanareykin, P.Schoessow
E. Wiesniewski (IIT), C. Li, H. Zha (Tsinghua), G. Ha(POSTECH).
A testbed for the development of high-gradient accelerating structures and wakefield measurements.
HG2013, Trieste, Italy, June 4th, 2013
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2. Primary mission R&D Beam Driven Dielectric Wakefield Acceleration
Funding 
High Energy Physics

3. Wakefields in Dielectric Structures2b 2a e Q Cu
short Gaussian beam
Key to the success:
Drive beam, drive beam and drive beam!
Charge 
sr  (Energy  or Emittance )
Bunch length 
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4. Dielectric-Loaded Accelerator Structure
Simple geometry
Inexpensive
Capable of high gradients
Easy to damp dipole modes
Tunable
Electric Field Vectors

5. outline High Gradient Concepts Applications
Collinear wakefield acceleration
Two beam acceleration (a.k.a. Parallel wakefield acceleration)
Applications
A high energy physics collider
An x-ray free electron laser
THz generation
The Argonne Wakefield Accelerator Facility
Then
Now
outline

6. concepts Collinear wakefield acceleration & Two-beam acceleration
(Parallel wakefield acceleration)
concepts

7. Collinear Wakefield Acceleration
Dielectric
Vacuum
Metal
Drive Beam
(EM power source)
Witness Beam
(accelerated beam)
Recent results (obtained for Linear Collider development):
1000MV/m level in the THz domain (UCLA/SLAC group)
100 MV/m level in the MHz domain (AWA/ANL group)

8. Two-beam acceleration (Parallel wakefield acceleration)
3. High Gradient Acceleration
Modulator
Klystron
250KV,
25MW, 8us
1.3GHz,
250AMPs
Mode Locked
2. RF power generation
UV Laser
1. Drive beam generation

9. e+ e- linear collider (a few) applications X-ray light source
THz generation
(a few) applications

10. HEP 1. e+ e- collider Current Approach: superconducting RF
25 MV/m, 0.5 TeV, 31 km
Current Approach: superconducting RF

11. Argonne Approach: Flexible Linear Collider*
HEP
250 MV/m, 3 TeV, 18 km
two-beam acceleration
Core of the two-beam acceleration concept:
Short rf pulse: tens of nanosecond
Modular TBA scheme: energy scalable easily
*(See C. Jing’s talk)

12. 2. Multiuser X-ray FEL User Facility
BES
Capable of serving
~2000 scientists/year
Laser-like X-rays
(like 4th generation light sources)
(like 3rd generation light sources)
Beam Spreader
~100 kHz X-rays
~1 MHz injector
50 MeV
2 GeV
experimental end stations
—Current Approach—
superconducting RF
$$$
Flexible x-ray beamlines (Tunable pulse length, seeded, 2 color seeded, SASE)

13. Argonne Approach dielectric wakefield accelerating linacs
BES
Collinear wakefield acceleration
~50 m
350m
750m
experimental end stations
~30 m
1. High Gradient (100 MV/m) DWFA linac
2. Room Temperature dielectric
~100 m
2 GeV
200 MeV
extremely low-cost alternative
~50 m
~50 m
Facility Footprint
350m x 250m
~25 m
3. Low Energy
Beam
Spreader

14. Ultra-flexible facility
Collinear wakefield acceleration
dielectric wakefield accelerating linacs
Flexible accelerator beamlines
Flexible x-ray beamlines
1.2 GeV
100 pC
0.5 keV
X-rays …
2.4 GeV
50 pC
End Stations
1 keV
X-rays …
Configurable
DWFA Accelerator
Configurable
FEL Array

15. 3. THz generation: Capability gap
BES
7.8GHz power extractor (40MW)
100MV/m gradient demonstration
Enhanced Transformer Ratio: 3.4
Tunable DLA structure
26GHz power extractor
Diamond breakdown experiment (300MV/m)
Bunch Train generation at the AWA
Wakefield Mapping diamond
THz source at AWA
Chirp correction
Tunable THz
GV/m
Tunable THz
High power (155 mJ)
Narrow band (1% BW)
1GHz 10GHz GHz 100GHz 300GHz THz 3THz
AWA
ATF BNL
FACET SLAC
1515
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16. Argonne Approach: dielectric wakefield accelerator-based
AWA (10nC / 6.3mm) 0.5 GW peak, 0.3THz, 320ps pulse, 1%BW, 155mJ pulse
Stage I Stage II Stage III
Energy modulation via self-wakefield
Chicane energy modulation conversion to bunch train
THz radiation wakefield structure
THz
Flexible: each step has a tuning range
Measured beam spectrum
Energy chirped rectangular beam
Energy modulated rectangular beam
Bunch train frequency content
Tunable 100% source: Range: THz
Pulse bandwidth: 1%
Energy in pulse: ~ mJ
narrow-band, tunable, ultra-high power THz source
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17. Then
The awa facility

18. Highlights of the Accelerator R & D group in the past
Invented the direct wakefield measurement technique.
First demonstration of collinear Wakefield Acceleration:
Dielectric Structures, Metallic Structures, and Plasmas
First Ever plasma wakefield acceleration in underdense regime (non-linear) (with UCLA).
First Ever 100 nC RF photocathode gun and Linac.
First Ever high power RF generation from dielectric wakefield structure accelerator.
First Ever dielectric based two beam acceleration experiment.
Discovered new multipactoring regime in dielectric structure.
Collinear wakefield
Drive beam generation
RF generation
Two-beam

19. The AWA facility (PAST, ca. 2008)
~ 1 meter
8 MeV
15 MeV
Experimental Area
soleniod lenses
YAG1
YAG2
Quads
Spectrometer
rf-gun
Laser In
Linac
Direction of beam propagation
AWA Laser System
Single bunch operation
Q = nC (reached 150 nC, World record?)
15 MeV, mm bunch length (rms),
emittance < 200 mm mrad (at 100 nC)
High Current: ~10 kA
Bunch train operation
4 bunches x 20 nC (current)
16 bunches x 5 nC (current)

20. RF power generation (PAST)
Dielectric Power Extractors
Dielectric-Loaded deceleration waveguide
7.8 GHz
40 MW
TM01-TE10 coupler
rf output port
Downconverted signal
26 GHz
20 MW
= GHz
 Power limited by drive beam

21. High Gradient Dielectric Wakefield Test (PAST)
#4 Q
Quartz
3.75
8.6 GHz
1.9 mm
7.49 mm
25.4 mm
1.33 MV/m/nC
75 nC
100 MV/m
Wakefield Measurements:
Q=75 nC e Cu
8.6 GHz
100 MV/m
 Gradient limited by drive beam

22. Now
The awa facility

23. Key components of the AWA Upgrade
15 MeV beam
Mg photocathode
Drive beam: 15 MeV  75 MeV
Restore two beam accelerator capability
Beamline switchyard
High quantum efficiency cathode
…Before
4. Cs2Te photocathode
After…
2. 15 MeV witness beam
1. 75 MeV drive beam: RF gun &
six rf cavities
3. beamline switchyard

24. Capabilities of the AWA Upgraded Facility
Higher RF power generation: 40 MW  ~ GW level
Higher gradients:100MV/m  0.5 GV/m in long structures
Sustained acceleration: witness DE: 1MeV  ~ 100 MeV
Restore two beam accelerator capability:
Drive bunches to excite wakefields & acceleration of witness bunch.
Beamline switchyard
two-beam-acceleration
staging
collinear wakefield acceleration
phase space manipulation

25. The AWA Upgrade drive beam
75 MeV
Direction of beam propagation
drive gun
Upgrade Goals
Original Drive Beam (Achievements)
Upgraded Drive Beam (Targets)
Single bunch operation
75 MeV
Q = nC
@ 100 nC
sz = 2 mm
High Current: ~16 kA
emittance < 200 um
Bunch train operation
10 bunches x 100 nC
32 bunches x 30 nC
Train Length = ns
Single bunch operation
15 MeV
Q = nC
@ 100 nC
sz = 3 mm
High Current: ~11 kA
emittance < 200 um
Bunch train operation
4 bunches x 20 nC
16 bunches x 5 nC
Train Length = ns

26. The AWA upgrade beamlines
experimental area
RF power generation
Collinear Wakefield
TBA
Wakefield Measurement
EEX
Bunch compression
75 MeV drive beam
15 MeV witness beam
75 MeV drive beamline installed Feb 2013
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27. Planned RF Power Generation
26GHz power extractor
Dielectric
Freq. (GHz)
Aperture (mm)
L (cm)
Q (nC)
z (mm)
Form factor
Grad. (MV/m)
Power (MW)
C-Band (7.8) 12 30
100
2.5
0.92 62
1107
X-Band (11.7) 10 80
0.83 79
1012
Ku-Band (15.6) 8 60
2.3
0.75 88
766
K-Band (26) 6
1.7
0.65 75
276
W-Band (91) 2 1
0.16 50 14
11.7GHz metallic power extractor is under development
Metallic (2pi/3 mode)
X-Band (11.7)
8.7 30 60
2.3
0.85 90
441
K-Band (26)
7.5 40 2
0.55
100
410

28. Planned Two Beam Acceleration Experiment
26GHz Stage I DWPE
a=3.5mm; b=4.53mm;
eps=6.64; L=30cm
drive (75MeV)
16 bunches x 60nC/bunch,
z=2mm
drive (65MeV)
-10MeV (loss)
RF Power Generation
767MW x15ns
26GHz rf
26GHz Stage II DLA
a=3mm; b=5.03mm;
eps=9.7; Vg=11%c; L=30cm
witness (10 MeV)
Q=1nC, z=1mm, e=1.5 um
witness (85 MeV)
+75 MeV (gain)
Ez = 250MV/m

29. Development of 26GHz short pulse DLA structure
parameters
value
ID / OD of dielectric tube
3 mm /5.025 mm
Dielectric constant
9.7
Length of dielectric tubes
105 mm Vg
11.13%c
R/Q
21.98 k/m
Q (loss tan=10^-4)
2295
Shunt impedance
50.44 M/m
Eacc for 316MW input
158 MV/m

30. Longer Term Goal: Staging for Two Beam Acceleration
Reverse the beam
Option 1
Drive Beam
stage I
stage II
Witness Beam
Drive
Witness 2m
0.5m
=2
Witness Beam
Drive Beam
Option 2
Reverse the RF
Delay the RF
Witness
Drive
*Option 3: Delay the beam
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31. Planned collinear wakefield acceleration @ AWA
drive z-direction
witness z-direction
Structure Parameters
Beam Parameters
Estimated Gradient
75MeV beam
8 bunches
40nC/per bunch
σz=2mm
Beam hole=3mm
Quartz tube
Freq.=29.9GHz
~500MV/m on axis

32. Planned demonstration of bunch shaping using a double-dog leg EEX beamline for high R
at the AWA Facility
The
Argonne Wakefield Accelerator Facility
 Low Energy (15 MeV) beamline
TDC B1 B2
RF Photocathode Gun
8 MeV
15 MeV
Linac
Quads
20 deg B4 B2 B3 B1
chirp
multiple masks on motorized actuator
x’ slope
x, y beam size
Key tunable parameters

33. Planned demonstration of bunch shaping using a double-dog leg EEX beamline
Example: Experiment I - Shaping capability
Multiple masks will be used to study the bunch shaping capability of the double dog-leg EEX beamline

34. Drive Diagnostic Beamline
To be installed Summer 2013
TEST
AREA
75 MeV
Longitudinal: Dp, p [MeV]
0.762m
dump
DIAGX8 1m
0.762m
End of linac
DIAGX7
0.4 m
1.5 m
1.0 m
1.0 m A 1m A
15 deg
Cav 6 A A
dump 2m
DIAGX3
DIAGX2 1m
DIAGX6
DIAGX5
DIAGX4
Def Cav
DIAGX1
Longitudinal: sz [mm]
Q[nC]
Transverse: ey,rms,normalized [mm]
Transverse: sx,y[mm]
USAF
target
YAG+
mirror
DIAGNOSTIC
CROSS A
Slit
Trim
OTR
BPM
ICT
Quad

35. summary AWA facility capabilities Applications Next steps 75 MeV Drive
Microbunch charge: 100 nC
Train charge: 1000 nC (10 x 100 nC, 32 x 30 nC)
Ramped trains & single bunches
15 MeV Witness (1-100 nC)
Applications
e+ e- collider
XFEL
RF-THz power generation
High Transformer Ratio
Two-beam acceleration
Collinear wakefield acceleration
Next steps
Drive and witness beamlines are installed, Awaiting final safety approval
Drive beamline commisioning – Summer-Fall 2013
Generate and characterize single bunches and trains
Condition 6 RF cavities
Install diagnostic beamline
Begin full beam commissioning at 75 MeV
First wakefield experiments – Fall 2013
Wakefield measurement system– 2014
summary