ferroelectric based technologies for accelerators
DESCRIPTION
AAC’08 , Santa Cruz CA, 2008. Ferroelectric Based Technologies for Accelerators. A.Kanareykin Euclid TechLabs LLC, Rockville, MD. This work is supported by the DOE, High Energy Physics. TEAM. A.Kanareykin , Euclid TechLabs LLC, Rockville, MD - PowerPoint PPT PresentationTRANSCRIPT
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
Ferroelectric Based Technologies forAccelerators
A.Kanareykin Euclid TechLabs LLC, Rockville, MD
This work is supported by
the DOE, High Energy Physics
AAC’08, Santa Cruz CA, 2008
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
A.Kanareykin, Euclid TechLabs LLC, Rockville, MD S.Kazakov, KEK, Tsukuba, Japan/Omega-P Inc., CT
E. Nenasheva, Ceramics Ltd., St. Petersburg, Russia, A.Tagantsev, EPFL, Lausanne, Switzerland
V.Yakovlev, Fermi National Lab
PROJECT IN COLLABORATION WITH YALE/OMEGA-P, INC., FNAL, ORNL/SNS, ELTECH
UNI. and ANL/AWA
TEAM
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
Outline
BST(M) ferroelectric: ultra fast switching material
Properties required for the accelerator applications
Material development: what have been done
Large diameter bars/rings fabrication
Testing by Omega-P, Inc.; L, X and Ka band designs
Parallel and transverse biasing field
Summary
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008 4
Ferroelectric Rings
A concept of phase shifter design (Omega-P, Inc.)
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
Applications of tunability
- Telecommunications - power - mW - W
- Radars - power - W - kW
- Accelerator technique - power - (0.5 -200) MW
Materials development
for the US Department of Energy
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
Applications of Ferroelectricsin Accelerator Technique
- RF tuning at X-band/Ka band
- RF tuning at L-band
- Fine tuning of dielectric structures
Tuning speed
low
10-20 ns
10-20 μs
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
Requirements
- Permittivity
- Relative tunability
- Tuning dc field
- Loss tangent (10 GHz)
- Commutation time
- Size of elements
kV/cm5010
500300
%2010
cm105.0
20 ns - 20 μs
< 3× 10-
3 f/tanδ ~ const !
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
FERROELECTRIC PROPERTIESFOR ACCELERATOR APPLICATIONS
- The dielectric constant should not exceed 300-500 to avoid problems caused by interference from high-order modes and extra wall losses.
- The dielectric constant should be variable by 15-20% to provide the required switching and tuning properties.
- Bias electric fields required to adjust the permittivity within this range should be reasonable, ~few 10’s of kV/cm - The loss tangent should be in the range of few10-3 or lower at 11-34 GHz to allow switching at 120-180 Hz rep rate.
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
FERROELECTRIC PROPERTIES
- very short intrinsic response time of ~10–10 - 10-11 sec ( 1 ns for circuits)
- high dielectric breakdown strength of 150-200 kV/cm
- high vacuum compatibility
- easy mechanical treatment (similar to conventional ceramic)
Ferroelectrics should have the following properties to operate in high-power rf switching and tuning devices:
- - 300-500 [500-600 current, recently reduced to 200-250]- variation - 10% - 20% at 50 kV/cm, [15% - E┴, >30% E║]- DC field - 10’s of kV/cm loss [20-60 kV/cm tested]- tanδ~10-2-10-3 at 11-35 GHz [5×10-3 at X-band, 5 – 10 ×10-4 700 MHz ]
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
Tuning of permittivity in ferroelectrics
dcE
RFE
)0(
)(
E
n
)0(
)()0(r
En
For small tuning (nr<<1)
3r )0(n
Ferroelectrics !!!
1)0(
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
Choice of material and approach
Composite: (Ba,Sr)TiO3 + dielectric (bulk ceramics)
0
500
1000
1500
2000
0 0.2 0.4 0.6 0.8 1
q
0
0.005
0.01
0 0.2 0.4 0.6 0.8 1
tan
q
(i) Use of BST with high 3
r )0(n
Spherical inclusion composite
(ii) Dilution with dielectric
0
0.05
0.1
0.15
0.2
0.25
0.3
0 0.2 0.4 0.6 0.8 1
q
)0(
)()0(
E
nr
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
MgO and Mg2TiO4
additives
1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
0 0.1 0.2 0.3 0.4 0.5concentration of inclusions, q
nreff
/nr
1
2
3
3D – theory
2D – theory
periodicnumericalsolution
Dependence permittivity ε′ (a), temperature Tm (b) and tunability kt for the samples BST (55/45) wt.% MgO (1) and Mg2TiO4 (2)
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
Ferroelectric properties vs. frequency and % wt of inclusions
0
0.05
0.1
0.15
0.2
0.25
0.3
0 0.2 0.4 0.6 0.8 1
q
Content of
Mg2TiO4,
% wt.
f =1 MHz
Qf ,GHz
Ku
( E,
2V/m) tan
15.0 460 0.00021 1200-1300 1.11
20.0 507 0.00031 1200-1300 1.08
30.0 375 0.00024 1100-1300 1.09
40.0 290 0.00025 1100-1150 1.1155 %BaTiO3 - 45%.SrTiO3 with 20% МgO
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
Developed materials
GHz10f
600500 kV/cm20dc E
(Ba,Sr)TiO3 based composite
(%)rn
Sengupta et al(patents)
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
BST(M) Ferroelectric: Size Effects
Dimension studies for the BSM-3 (left) and BSM-4 (right) ferroelectric samples with thickness of 0.1 – 0.5 mm.
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
BST(M) Ferroelectric: Bulk Sample Measurements
(Omega-P, Inc.)
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
Experimental Setup, ns Scale Switching Time
Pictures of the experimental setup for the time response testing of the
ferroelectric samples to high pulse voltages.
time,s
-10x10-9 -5x10-9 0 5x10-9 10x10-9 15x10-9 20x10-9
Uco
ntro
l(V)
0
500
1000
1500
2000
2500
3000
time,s
-10x10-9 -5x10-9 0 5x10-9 10x10-9 15x10-9 20x10-9
Ud(
mV
)~C
-15.0
-12.5
-10.0
-7.5
-5.0
-2.5
0.0
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
Various Samples of BST(M)
Various Samples of BST(M)
DC and Pulse Tunability Measurements
Kdc =C(0)/C(Udc )=C(0)/Cdc corresponds to capacitance value Cdc measured in 1 min after themoment of Udc switching on).
Kdyn =C(0)/Cpulse (Um) =C(0)/Cpulse Cpulse corresponds to the end of the leading front of the 20 ns pulse.
×10 kV/cm
×10 kV/cm
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
FAST ACTIVE X-BAND HIGH POWER PHASE SHIFTER
* Developed by Omega-P, Inc.
S. Kazakov et al “First Measurements of RF Properties of Large Ferroelectric Rings "
dcRF EE
Ferroelectric ring elements for the X-band high power phase shifter. The same technology will be used for the L-band tuner fabrication.
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
Loading with parallel bias
dcRF EE
Ferroelectric L-band Reflecting Phase Shifter
RF field, TEM mode
dc field
Copper electrodes
ferroelectric ring
* Developed by Omega-P, Inc.
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
L-band Planar Design (Omega-P, Inc.)
S. Kazakov et al. EPAC’08* Developed by Omega-P, Inc.
dcRF EE
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
Problem of transverse bias
d
3d
dcE
RFE
dcRF EE
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
BST(M) ferroelectric group of compositions
composition ε tanδ×10-3, 10 GHz Kparallel, 4 V/μ Ktransverse, 4 V/μ
BSM-1 ~520 4.0 1.16 1.08 BSM-2 ~420 3.4 1.08 1.05 BSM-3 ~580 5.0 1.27 1.16 BSM-4 ~600 8.7 1.50 1.22
E.Nenasheva. “Development of A Low Loss Microwave Ferroelectric Material for the High Power Tunable Devices”
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
Effect of dc bias orientations
longitudinal transverse
E
acE
EACE
)0(
)(
E
n ?n
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
Examples: nvs n
Edc, kV/cm
n (E)
1
2
3
0 5 10 15 20 251
1.5
2
2.5
3
kV/cm,E
3
2n
n
n
n
(Ba0.65Sr0.35)TiO3 at 3150K ; data by Daimond (1961)
1
2
3
n (E)
Edc, kV/cm
0 5 10 15 201
1.2
1.4
1.6
kV/cm,E
n
n
3
2n
(Ba0.8Sr0.2)TiO3 at 333 0K data by Pertov et al (1971)
n
Acceptable loss of tunability when passing from n‖ to n┴
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
BST(M): what have been done ?
The group of materials have been developed: from BSM-1 to BSM-4 Pulse measurements have been carried out : < 10 ns switching time !
Theory of the BST(M) composite ferroelectric have been developed
Transverse dc bias feasibility has been demonstrated
Dielectric response and tunability have been measured/mechanical
Dimension effects have been studied
Metallization technology has been developed
First direct BST bulk sample measurements
First cold test of the L-band fast shifter: 1200 phase shift
Tunable DLA structure cold test : temperature and dc bias tuning
AAC’08 Santa Cruz CA, July 27th - August 2nd
2008
to be done:
- Material improvement with lower loss tangent
(Euclid)
- Vacuum testing (Euclid/ANL)
- High power testing at X-band (Omega-P/NRL)
- Beam testing of the tunable DLA (Euclid/ANL)
- Fast switching of the L-band phase shifter (Omega-
P)
BST(M): what will be done ?
XI-Electroceramics, Manchester, UK August 31, 2008