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US HG Research Collaboration Workshop, SLAC, 2011
PROGRESS ON HG WAKEFIELD ACCELERATOR DEVELOPMENT
EUCLID&AWA COLLABORATION
A. Kanareykin for Euclid/AWA CollaborationEuclid Techlabs LLC
US HG Research Collaboration Workshop, SLAC, 2011
Euclid Techlabs LLC: DLA collaboration
Euclid Techlabs, Rockville, MD: - -C.Jing, S.Antipov, P.Schoessow, and A.Kanareykin -P. Avrakhov (FNAL)-S. Zou (NRL)
AWA of Argonne Nat. Lab, Chicago: Argonne Wakefield Accelerator:M.Conde, J.G.Power, R.Conecny, Z.Yusof, AWA and W.Gai
Naval Research Lab, Washington, DC-S.Gold- J. Butler
FACET Collaboration:SLAC, UCLAJ. Rosenzweig, G.Travish,M.Hogan…
THz:
US HG Research Collaboration Workshop, SLAC, 2011
DLA Issues
Drive Beam – Beam Train - High Gradient DLA
Dielectric Material Beam Tests
Dielectric - Wakefield Power Extractor
Tunable Dielectric Based Accelerator
Energy Transfer: High Transformer Ratio
Beam Handling, Beam Breakup (BBU)
Dipole Mode Damping
Dielectric Based Accelerator issues: high gradient – drive beam, power extraction, tuning, efficiency, beam control (BBU).
US HG Research Collaboration Workshop, SLAC, 2011
Outline
Transformer Ratio Experiment (C.Jing’s talk)
Tunable DLA (C.Jing’s talk) and Nonlinear Materials for DLA
26 GHz Power Extractor
BBU Studies for DLA
PETS power extractors
Short Pulse High Gradient DLA Structure (M.Conde’s talk)
Multipactor DLA Studies (S.Antipov’s talk)
GHz Diamond Based DLA Structure
FACET DLA
US HG Research Collaboration Workshop, SLAC, 2011
Drive Gun
Linac & Steering Coils Quads
Wakefield Structure
ExperimentalChambers 4.5 m
GVGV
YAG1 YAG2
Spectrometer
YAG5Dump/Faraday Cup
Slits
YAG4YAG3ICT1
ICT2 BPM
Single bunch operation– Q=1-150 nC– Energy=15 MeV– High Current = 10 kAmp
Bunch train operation up to 64 bunches x 50 nC 50 ns long
Materials for Dielectric Loaded
Acceleratorb a
Q
Cu
>100 MV/m gradient demonstrated
US HG Research Collaboration Workshop, SLAC, 2011
Materials
(f = 9,4 GHz)
tan
(f = 9.4 GHz)
Cordierite 4.50.2 210-4
Forsterite 6.30.3 210-4
Alumina 9.80.3 110-4
D-10 9.70.2 1.510-4
D-13 13.00.5 210-4
D-14 14.00.5 0.610-4
D-16 16.00.5 210-4
MCT-18 18.03% 110-4
MCT-20 20.05% 1.510-4
V-20 20.05% 310-4
V-37 37.05% 310-4
material tan, X-band /, 4 V/m BST+MgO 350-500 510-3 1.30
material tan, X-band tthermo-conductivity
diamond, 5.7 110-4 2500 W/m/0K
material tan, X-band tthermo-
conductivity quartz , 3.8 110-4 1.4 W/m/0K
Dielectric Materials for the HG Accelerator Applications*
Low loss microwave ceramic (1994-2011)
Composite ferroelectric (2003-11)
CVD Diamond (2005-11)
Quartz (2002-11)
US HG Research Collaboration Workshop, SLAC, 2011
Euclid efforts in the WF experiments at Argonne
Experiment of 26GHz dielectric wakefield power extractor in 2009 16ns,1MW & 6ns, 20MW 26GHz rf pulse were measured. BBU was observed.
Experiments of transformer ratio enhancement in 2007, 2010 Successfully enhanced the transformer ratio to 3.4 by using ramped bunch train technique. The tunable DLA demonstration with the beam test in 2010. Developed the tunable DLA structure, bench tested. Beam test has been completed few weeks
ago. Tuning range of ½ λ has been demonstrated The planned test of the GHz diamond structure
Finished simulation and engineering design. The planar structure is being assembled. Beam experiment - in Spring of 2011. Progress on cylindrical structure development.
US HG Research Collaboration Workshop, SLAC, 2011
Transformer Ratio Experiment by joint effort from Euclid Techlabs and AWA*
Measured Enhancement
factor of R2/R1=1.31
Inferred R2=2.3
Reference: Schutt et. al., Nor Ambred, Armenia, (1989)
zd d
W -
W+
d
(z)
R2=3.4
(2007)
(2010) *talk J.Jing
US HG Research Collaboration Workshop, SLAC, 2011
Temperature tuning of 14 MHz/0K
forsterite BST(M)
Tunable DLA Temperature Tuning*
*C.Jing’s talk
US HG Research Collaboration Workshop, SLAC, 2011
Tunable DLA Beam Experiment*
*C.Jing’s talk
Temperature tuning of 14 MHz/0K
Wakefield
Frequency Shift
US HG Research Collaboration Workshop, SLAC, 2011
BST(M) Ferroelectric Based L-band High Power Tuner
30 ns switching time
Collaboration with Omega-P and FNAL
Pulse steepening on NL planar transmission line
US HG Research Collaboration Workshop, SLAC, 2011
26 GHz Power Extractor and BBU Experiment
BBU mitigation with quadrupole channel
20 nC beam; tapered F-D-F quad array
US HG Research Collaboration Workshop, SLAC, 2011
Transverse Beam Dynamics in the DLA
Distance behind the bunch, cm3210-1
Wak
efie
ld ,
MV
/m1
0,8
0,6
0,4
0,2
0
-0,2
-0,4
-0,6
0
5
10
15
20
25
0,01 0,05 0,1 0,15 0,2 0,25 0,3 offset, cm
Transverse field, MV/m
Collaboration with Dynamic Software and ANL
US HG Research Collaboration Workshop, SLAC, 2011
Multibunch BBU in the DLA
v=cR
R’Fr
Fz
3D beam implementation Phase space input/output
Parmela files import opportunity Improving Particle Push Algorithm
(3D) 2D FODO focussing F(x)~x, F(y)~y Improved results visualization Main parts to be ready by February
2008
US HG Research Collaboration Workshop, SLAC, 2011
7.8 GHz Transverse Mode Damped DLA Structure*
• A new transverse mode damped DLA structure has been proposed.
•A 7.8 GHz prototype has been built and bench tested.
• Beam test will be performed at AWA facility.
Comparison of the 7.8GHz Conventional and the Transverse mode Damped DLA structure.
Freq. Q in conventional DLA structure
Q in transverse modes damped DLA structure
Accelerating mode (TM01)
7.8GHz 6964* 6738*
Transverse modes (HEM11)
6.34GHz 6866* 23*
Collaboration with ANL
*C.Jing, this workshop
US HG Research Collaboration Workshop, SLAC, 2011
Projects
Development of a Dielectric-Based Short RF Pulse Two Beam Accelerator Prototype Module Unlike the most of the present accelerator designs pulse with lengths of 150-400 ns and gradients ~100 MV/m as the operational parameters, we propose a short pulse (~20 ns), high repetition rate (>1 kHz), high gradient (>200 MV/m) accelerator technology.
THz Dielectric Wakefield Accelerating Structure. This project will develop a manufacturing technology of artificial diamond fiber to be used in dielectric loaded accelerating structures. When developed, this structure will sustain a record high accelerating gradient in THz frequency range.
Development Of A 12 GHz Dielectric-Based Wakefield Power Extractor for Potential CLIC Applications Dielectric based high power radio frequency (rf) generator offers the possibility of reduced cost and higher efficiency for applications in the next generation high energy physics machine to meet the particular requirements of CLIC.
Multipactor Suppression In Dielectric Loaded Accelerating Structures Using Vacuum Channel Surface Modification This project will study ways to eliminate a form of energy absorption that is currently the main obstruction to widespread use of the dielectric based particle accelerators.
Dielectric Collimators for Linear Collider Beam Delivery this project will develop a special device to control electron bunch of the future linear collider. The use of new software and materials that our company has developed is expected to lead to improved performance and efficiency.
US HG Research Collaboration Workshop, SLAC, 2011
Developing a Dielectric PETS* (CLIC)
* Funded by DoE SBIR Phase I. Thanks for help from AWA, CLIC, and SLAC.
In order to have a high power rf test at SLAC, the 1st structure is scaled to 11.424GHz.
12GHz Quartz-Based Power Extractor Using CLIC Parameters: σz=1mm, Q=8.4nC, Tb=83ps
Freq 12GHz
Effective Length 23cm
Beam channel 23mm
Thickness of the dielectric tube 2.58mm
Dielectric const. 3.75(Quartz)
Q 7318
R/Q 2.171k/m
Vg 0.4846c
Peak surface Gradient 12.65MV/m
Steady Power 142MW
US HG Research Collaboration Workshop, SLAC, 2011
12 GHz PETS is under construction:
The rest of parts are on the lathe; will be done this week, then will be shipped for the brazing.
US HG Research Collaboration Workshop, SLAC, 2011
• fast rf rise time (<3ns)Broadband (>150MHz)• less filling time Large (~10%c) Vg.
3ns 3ns
Trf=28ns
Tf=9nsTbeam=16ns
%26rf
beam
rf
sloadbeambRF T
T
P
LEI
6.5A 267MV/m
0.3m
1.264GW
16ns
25ns
Development of a Short Pulse High Gradient DLA Structure*
AWA/Euclid proposed a 26GHz short pulse collider concept.
RF pulse structure
Requirements for the accelerating structure
* Funded by DoE SBIR Phase I. *M.Conde’s talk
US HG Research Collaboration Workshop, SLAC, 2011
Broad band fast rise time
500MHz
DLA structure (const. impedance)
Design of the Short Pulse DLA
Broadband coupler (scaled from SLAC X-band coupler)
Vg~11%c; R/Q~22k/m; R~50.5M /m
US HG Research Collaboration Workshop, SLAC, 2011
Projected rf power and achievable gradient in AWA 75MeV beamline
Estimated PowerAWA facility
75MeV beam16 bunches60nC/per bunchz=2mm
26GHz DWPE
767MW, 15ns, 26GHz rf (10MeV
loss)
26GHz DLAEstimated Gradient
250 MV/m
talk M.Conde
US HG Research Collaboration Workshop, SLAC, 2011
Multipactor Studies
0 50 100 1500
5
10
15
20
25
MP
-indu
ced
pow
er lo
ss, %
gradient, MV/m
MAX SEY 2.4MAX SEY 5 Simulations:
Multipactor power loss decreases at
HG
Longitudinal Transverse
• groove type • groove dimensions• length• TiN coating
we are all set to test ~ 10 different configurations:
S.Antipov’s talk Collaboration with UMD,
NRL and ANL
US HG Research Collaboration Workshop, SLAC, 2011
Motivation for CVD Diamond for DLA
Element Six
Element Six
CVD DIAMOND PROPERTIES:
- DC BREAKDOWN THRESHOLD OF ~ 2 GV/m
- LOSS FACTOR DOWN TO 5-9 x10-5 AT 30-140 GHz
- HIGHEST THERMAL CONDUCTIVITY
- DC CONDUCTIVITY - HIGH REPRATE.
- MULTIPACTING CAN BE SUPPRESSED
- CVD DEPOSITION NOW CAN BE USED TO FORM CYLINDRICAL WAVEGUIDES
US HG Research Collaboration Workshop, SLAC, 2011
35 GHz Diamond Based DLA Structure
CVD diamond tube fabrication
US HG Research Collaboration Workshop, SLAC, 2011
500 600 700 800 900-5000
0
5000
10000
15000
20000
25000
30000
35000
cts
8-30
-1
Wavelength (nm)
center
500 600 700 800 900-5000
0
5000
10000
15000
20000
25000
30000
35000
cts
8-3
0-2
Wavelength (nm)
edge
500 600 700 800 900
Wavelength / nm
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
11000
12000
13000
Cou
nts
High Electronic Quality Cylindrical Diamond DLA (I)
US HG Research Collaboration Workshop, SLAC, 2011
High Electronic Quality Cylindrical Diamond DLA (II)
Laser light
Laser light
Daylight
Outer surface facets
facets
cylindrical
US HG Research Collaboration Workshop, SLAC, 2011
Planar Diamond Structure
Bunch length 1.5 mm
Beam gap 4.0 mm
D thickness 1.2 mm
width 8 mm
length 5.0 mm
First CVD diamond in a dielectric accelerating structure
> 100 MV/m gradient using AWA beam
Breakdown test using 20 micron – wide artificial scratch on the diamond surface (0.5 GV/m level fields)
Structure is short, TM110 – based . Wake is a single mode at ~ 26 GHz
US HG Research Collaboration Workshop, SLAC, 2011
Planar Structure Design
Avoiding hot spots on diamond holder
beamDiamonds E6 ...scratched
There will be a ~500% field enhancement in the scratch / groove
beam
US HG Research Collaboration Workshop, SLAC, 2011
Diamond Groove SEM Image
SEM: Z. Yusof
Cut: J. Butler (NRL)
Image: “BEFORE”
US HG Research Collaboration Workshop, SLAC, 2011
The Structure Holder
Most the holder parts are completed
One modification needed (RF probe)
Cleaning (parts, diamonds)
S. Doran
US HG Research Collaboration Workshop, SLAC, 2011
SEE COEFFICIENT
Multipacting is suppressed by treating the diamond surface during the CVD growth of the diamond, in particular, dehydrogenation of the surface to decrease the secondary electron yield. SEE coefficient is reduced ~ 1.
I.L. Krainsky et al. NASA Report/TP—1999-208692, (1999)
Collaboration:- NRL, Surface Chemistry (J.Butler)
- Genvac Aerospace Inc./NASA
- Coating Technology Solutions, Inc. A.Kanareykin, P.Schoessow et al,
EPAC 2006, Edinburgh, pp. 2460-2462, (2006).
US HG Research Collaboration Workshop, SLAC, 2011
ID=80 μm (a=40 μm )OD= 152 μm (b=76 μm)b - a= 30 μm (diamond thickness)
Planar or Cylindrical THz DLA ?Gradient
Distance behind the bunch, cm0
Wak
efie
ld ,
V/m
10,000,000,000
8,000,000,000
6,000,000,000
4,000,000,000
2,000,000,000
0
-2,000,000,000
-4,000,000,000
-6,000,000,000
-8,000,000,000
-10,000,000,000
b a
Q
w
0 5 103 0.01
1 104
5 103
0
5 103
1 104
z-Vt, cm
Ez, M
V/m
Both structures ~ 2 GV/m/nC
2a=80 μm, a= 40 μm, b= 70 μm b - a= 30 μm (diamond thickness)w= 300 μm
2 GV/m/nC 2 GV/m/nC
US HG Research Collaboration Workshop, SLAC, 2011
Conclusions
Transformer Ratio Experiment has demonstrated R>3.4 for two bunch train
Tunable DLA has been developed with the tuning range of 15 MHz/0
26 GHz Power Extractor has been demonstrated
BBU code has been developed and used for PE development
12 PETS power extractor for CLIC is under construction
High Gradient DLA Structure proposed for the new Short Pulse collider
GHz Diamond Based DLA Structure test are coming
Multipactor simulations showed reduced power loss at 150 MV/m
FACET DLA structure is being fabricated