a. kanareykin, euclid techlabs llc, atf users meeting 2012 beam manipulation by thz self-wakefield...
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A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
Beam manipulation by THz self-wakefield at ATF (I)
A.Kanareykin Euclid TechLabs LLC, Gaithersburg, MD
ATF Users Meeting BNL, April 26-27, 2012
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
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Outline
Proposed experiments Chirp Compensation Energy Modulation Transformer Ratio Enhancement
What technology, software and material we’ve got to accomplish it ?
Beam manipulation Electromagnetic simulations software Diamond based structures Nonlinear materials
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
We are pursuing three experiments at the ATF, two related to beam manipulation by its self-wakefield and one – a direct wakefield acceleration: A demonstration of a tunable beam energy chirp compensator. The conversion of self-wake energy modulation into a THz bunchtrain. A demonstration of enhanced transformer ratio by a shaped beam.
Proposal
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
Motivation
Light source is an intrinsic requirement for current and future scientific research. Particularly, ultrashort x-ray pulses are a powerful tool for addressing grand challenges in science.
One particular obstacle limiting construction of FEL light source facilities is the cost, particularly, linacs to provide high energy, high brightness beam. wanted: gradient >100MV/m, peak current >1kA,
rep~1MHz, E~ a few GeV, etc. In the past few years, the field of high gradient acceleration,
aimed at the future high energy linear collider, achieved many impressive results. e.g. GV/m level in THz; 100 MV/m in MW demonstrated
in DWA structures; wanted E ~200- 300 MV/m, R>10.
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
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Currently Available Beam Resources for Euclid’s Experiments.
Facility Main parameters
ANL/AWA 15MeV/ 75 MeV, z = 1-2 mm, Q = 10-100 nC, yielding ~ 100-300 MV/m at 10-30 GHz or ~GW beam power; TBA;
BNL/ATF 60 MeV, tunable z = 100 um-1.5mm, r~100um, 0.3-0.5 nC, 0.3-0.8 THz
SLAC/FACET 23 GeV, z = 20-30 um, r ~ 10 um , Q = 1-3 nC, 0,5-1,0 THz frequency, 1-10 GV/m
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
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Euclid THz DWA structures at FACET
e-
Kraken Chamber by UCLA/SLAC
Through Collaboration E201 (UCLA/SLAC/Euclid)
23GeV, 3nC, r~10µm, z~30µm
Euclid Structure
Dimensions
Exp. Grad. (3nC, z~30µm)
Quartz tube 1
400µm ID 550µm OD
1.6GV/m ~0.6THz
Quartz tube 2
300µm ID 415µm OD
2.5GV/m ~0.63THz
Alumina tube
508µm ID 790µm OD
0.9GV/m multimode
Sapphire tube
790µm ID 1090µm OD
0.5GV/m multimode
Diamond slab
150µm gap 90µm thickness
1GV/m multimode
Diamond tube
105µm ID 165µm OD
8.8GV/m ~1THz
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
Chirp compensation: The free electron laser (FEL) is considered to be the main candidate for a short wavelength (UV to X-ray), short pulse (femto- to attosecond) light source. Demands: (1) high repetition rate (~MHz) (2) high peak current (a few kA); (3) low emittance (sub-micron emittance).
At the output of the last compressor - a small energy chirp. It is required that this relatively small energy spread be compensated using a specially designed device. This compensation can be realized by a simple wakefield device. In 2011 we demonstrated energy compensation at the ATF [Antipov et al, PRL, 2012]. We now propose to test and demonstrate the first tunable energy chirp compensating system.
Chirp Compensation
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
Energy modulation conversion into a THz bunchtrain:a follow up experiment to our 2011 experimental program [Antipov et al, PRL 2012]. We observed energy modulation produced by a self-wake on an originally chirper beam. This energy modulation can be transferred into density modulation via a chicane. We propose to perform this transformation at the ATF. This process of self-wake energy modulation and a follow up conversion into a THz bunchtrain is the basis of an inexpensive, table top, high power THz source.
Energy modulation
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
The transformer ratio: a high transformer ratio leads to a higher overall efficiency. The experiment will be the first demonstration of enhanced transformer ratio from a triangular shaped beam. This experiment is similar to the diamond structure wakefield mapping accomplished at the ATF in 2011 [Antipov et al, APL 2012]. We propose to use a motorized mask to produce a drive beam followed by a witness beam at variable distance.
Transformer Ratio Enhancement
z
z
EwR
w E
(z)
z W -
W+
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
Ramped BunchReference: Bane et. al., IEEE Trans. Nucl. Sci. NS-32, 3524 (1985)
c
(z)W+
W-z
Ramped Bunch Train
Reference: Schutt et. al., Nor Ambred, Armenia, (1989)
zd d
W -
W+
d
(z)
Measured Enhancement
factor of R2/R1=1.31
Inferred R2=2.3
R2=3.4
(2007)
Transformer Ratio Enhancement Using a Bunchtrain
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
Key Technology --- bunch shaping to enhance transformer ratio
Triangular bunch
Double triangular bunch
TR~10
TR~17
(STAB, 2012)
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
Simplified sketch of the EEX beamline.
Bunch charge 30 nC
Beam energy 30 MeV
Beam size (RMS x\y) 0.7 cm\0.3 cm
Bunch length (RMS) 1.7 mm
Energy divergence (RMS) 95 keV
EEX line dipole length 0.5 m
Bending angle 45º
Deflect cavity voltage 3.6 MV (peak)
Drift space (between 2 dipoles) 0.3 m
An example ---using EEX technique
Refer to Sergey’s
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
Software Developed for DLA
Waveguide’09
Multibunch’09
Rectangular’11
BBU’300
Energy Modulation’11
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
Distance behind the bunch, cm
3210-1
Wak
efie
ld ,
MV
/m
1
0,8
0,6
0,4
0,2
0
-0,2
-0,4
-0,6
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
dielectric ε Tan δ
(10 GHz) Frequency
(GHz) Experiment, reference
Quartz 3.8 <1×10-4 11.4 High Gradient Standing Wave
Cordierite 4.7 <1.5×10-4
7.8
8.6
21
11.4/30
7.8 GHz TBA Power Extractor
High Gradient Standing Wave
21 GHz DL Power Extractor
Two Channel High Transformer Ratio
Diamond 5.7 <1×10-4 26-35 High Gradient Standing Wave
Forsterite 6.3 <2×10-4 11.4
26
Traveling Wave DLA
26 GHz DL Power Extractor
Alumina 9.8 <1×10-4 11.4 Dual Layer DLA (outer layer)
MgTiO3 - Mg2TiO4
16 <1.2×10-4 13.6 Collinear High Transformer Ratio
MCT (Mg,Ca)TiO3
20 <2×10-4 7.8 Two Beam DLA Accelerator
BaTi4O9 37 <3×10-4 11.4 Dual Layer DLA (inner layer)
CaTiO3-LaAlO3 38.1 <5×10-4 1-30
(multimode) Multimode DLA bunch train generation
Dielectrics Tested as DLA Loading
THz experiments at ATF
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
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
- MULTIPACTING CAN BE SUPPRESSED
and
CVD DEPOSITION NOW CAN BE USED TO FORM CYLINDRICAL WAVEGUIDES
Motivation for CVD Diamond for DLA
Element Six
Element Six
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
35 GHz Diamond Based DLA Structure
CVD diamond tube fabrication
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
THz Diamond Tubes
(Bristol University, UK)
Scanning electron microscope images of a THz diamond microstructure produced using the hot wire deposition technique.
THz diamond structure:ID = 100 μm, thickness 70 μm,1 cm long
Single crystal diamond
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
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Experimental Report on A Diamond Based Wakefield Structures (DoE SBIR ext. Phase II project, 2012)
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
Wakefield Mapping of a Diamond Slab Structure at BNL/ ATF
0.25 THz
• 1st wakefield mapping experiment in THz regime (June 2011). • 1st wakefield acceleration observed in THz regime.• S. Antipov, et al, App. Phy. Lett. March 2012.
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
High Grad. Breakdown Study of A Diamond Slab Structure @ ANL/ AWA
Bunch length 2~2.5 mm
Beam gap 4.0 mm
D thickness 1.2 mm
width 8 mm
length 5.0 mm
50MV/m per 50 nC beamOur goal is to perform first WF experiment with Diamond-based DLA, test for breakdown
Structure is short, TM110 – based Wake is a single mode at ~ 26 GHzQ = 2800 (decay time ~35ns)
*AWA facility can generate up to 100nC beam with σz = 2.5 mm (14 MeV)
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
Field Enhancement in the scratch
Avoiding hot spots on diamond holder
beam
Diamonds (E6) ...scratched
Field is ~5 times higher
beam
50nC 250 MV/m
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
Diamond groove SEM image
SEM: Z. Yusof (AWA)
Cut: J. Butler (NRL)
Image: “BEFORE”
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
High Gradient Beam Test
afterbefore
72nC (σz=2.5mm) went through which is eqv. to ~ 0.3 GV/m gradient on axis for decay time τ ~ 35ns.
Preliminary examination shows No evidence of breakdowns during the beam test. More examinations or additional test will be carried out.
SEM: Sergey Antipov, Euclid and Sergey Baryshev, MSD ANL
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
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Nonlinear Ferroelectric Materials for DLA Based Accelerator Structure (DoE SBIR. Phase II project, completed)
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
Temperature Tuning Effects in Dielectric-Based Accelerating Structure
forsterite BST(M)
ε(E) for ferroelectric dielectric composite
Temperature tuning 14 MHz/0K
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
Relative permittivity as a function of electric field strength for a composite ferroelectric dielectric
63 20 8 10
1 21
/.E( n ) n ( n )
x
Lineout of the electric field on axis for different beam intensities. Red: Q=0.03 nC; Blue: Q=0.30 nC; Green: Q=3 nC (cf. Fig.21). For ease of comparison the data is scaled to Q=3.0 nC.
Nonlinear Effects at FACET DLA
DoE SBIR. Phase I, to be submitted 2012
A. Kanareykin, Euclid Techlabs LLC, ATF Users Meeting 2012
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Euclid DLA Experiments planned in 2012
• THz DWA at FACET /SLAC (April 2012)
•THz DWA test at ATF/BNL (fall 2012)
Chirped electron bunch energy compensation for an x-ray light source, Phase II submitted, BES
Enhanced transformer ratio using a double triangular beam generated with the E-EX technique, Phase II submitted, HEP