x band choke structures a. dian yeremian slac national accelerator laboratory
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X Band Choke Structures A. Dian Yeremian SLAC National Accelerator Laboratory 4th Annual X-band Structure Collaboration Meeting , May 3rd - 5th, 2010 CERN. X Band Choke Structures . Acknowledgments Thanks very much to Sami Tantawi and Valery Dolgashev who have - PowerPoint PPT PresentationTRANSCRIPT
X Band Choke Structures
A. Dian YeremianSLAC National Accelerator Laboratory
4th Annual X-band Structure Collaboration Meeting,May 3rd - 5th, 2010
CERN
A.D Yeremian, 3 May 2010
Acknowledgments
Thanks very much to Sami Tantawi and Valery Dolgashev who haveinspired and help me to get involved in the world of high gradient rf structures.
The structures, I will be discussing here, are all inspired by Valery Dolgashev.
X Band Choke Structures
A.D Yeremian, 3 May 2010
Motivation
3 Structures
- Choke Flange
-Triple Choke
-Full Choke
X Band Choke Structures
A.D Yeremian, 3 May 2010
Motivation
X Band Choke Structures
High gradient RF breakdown studies include structures of various materials, some of which do not braze well or should not be brazed. There is also the desire to view the hotspots on the cell irises by a high speed camera or microscope without perturbing the electromagnetic fields by the viewport pipe. Reducing the gradient at the outer wall of the cell permits us to do these studies.
A.D Yeremian, 3 May 2010
X Band Choke Structures
1. The choke flange was designed to replace the flange with an rf joint by an rf-lip. The joint is not always perfect and deteriorates with assembly/disassembly cycles.
2. The triple choke structure was designed in order to significantly reduce the electric and magnetic fields on the rf joint.
3. The full choke structure was designed to reduce the electric and magnetic fields at the outer radius of the cell so that we can put a view port without perturbing the fields. With the view port, a microscope or any other device could be used to view both high electric and high magnetic field areas between and during rf pulses.
A.D Yeremian, 3 May 2010
X Band Choke Flange
A.D Yeremian, 3 May 2010
0.1mm 2 mm4 mm
chokeR = 2.5 mm
30 m
m
11.424 GHz Choke Flange
X band Choke Flange Optimized Assuming Ideal Conducting Walls
11.00 11.20 11.40 11.60 11.80 12.00Freq [GHz]
-80.00
-70.00
-60.00
-50.00
-40.00
-30.00
-20.00
-10.00
dB(S
(Wav
ePor
t1:1
,Wav
ePor
t1:1
))
Ansoft Corporation HFSSDesign1XY Plot 2
Curve Info
dB(S(WavePort1:1,WavePort1:1))Setup1 : Sw eep1
F = 11.4236 GHzReflection (S11) = -78.2dBBandwidth = 120 MHz
120 MHz
A.D Yeremian, 3 May 2010
X band Choke Flange Electric Fields
100 MW input, on-axis E=33.6MV/m, at the top of the gap E=125kV/m or 1.25kV/cm
a) Autoscaled to demonstrate max field on axis b) Manually scaled to demonstrate max field at top of choke gap
A.D Yeremian, 3 May 2010
X band Choke Flange Magnetic Fields
100 MW inputOn the pipe H=57 kA/m, at top the of the gap H=225A/m
a) Auto-scaled to demonstrate max field on axis
b) Manually scaled and axis region in zoom to demonstrate max field at top of choke gap and on axis
A.D Yeremian, 3 May 2010
Dipole Quadrupole Sextupole
X band Choke Flange Trapped Modes Scanning from 11 GHz Looking for 3 modes
A.D Yeremian, 3 May 2010
Dipole
X band Choke Flange Trapped Modes Dipole Mode Electric Fields
Mode 1 (not trapped)
Mode 2 (not trapped) Mode 3 (not trapped)
No trapped modes! A.D Yeremian, 3 May 2010
Choke Flange Frequency Scan Overlay
-80
-70
-60
-50
-40
-30
-20
-10
11 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 11.9 12
Frequency (GHz)
Ref
lect
ion (d
B)
perfect conductor S Steel Cesic
At f = 11.4236GHz - 78dB - 60dB - 42dB
(11.392 GHz , - 47dB)
A.D Yeremian, 3 May 2010
A.D Yeremian, 3 May 2010
X-band 1C-SW-A3.75-T2.6 Triple Choke Structure
f = 11.424038 GHz
4 mm
chokeR = 2.5 mm
30 m
m
A.D Yeremian, 3 May 2010
11.410 11.415 11.420 11.425 11.430 11.435Freq [GHz]
-30.00
-25.00
-20.00
-15.00
-10.00
-5.00
0.00
dB(S
(Inpu
tPor
tCpl
r:1,In
putP
ortC
plr:1
))
Ansoft LLC HFSSDesign1XY Plot 1
m1
Curve Info
dB(S(InputPortCplr:1,InputPortCplr:1))Setup1 : Sw eep1
Name X Y
m1 11.4222 -26.3351
X-band 1C-SW-A3.75-T2.6 Triple Choke-Cu Structure
Frequency = 11.424038 GHzBandwidhth = 1MHzReflection (S11) = -26.3dBQo = 8660Qe = 7771Coupling = 1.11
1 MHz
A.D Yeremian, 3 May 2010
0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00Distance [mm]
0.00E+000
5.00E+007
1.00E+008
1.50E+008
2.00E+008
2.50E+008
3.00E+008
3.50E+008
Com
plex
Mag
_E
Ansoft LLC HFSSDesign1XY Plot 4
m1
m2
m3
Name X Y
m1 27.7200 152518884.2512
m2 40.8100 304028128.6167
m3 54.6700 151671480.9496
Curve Info
ComplexMag_ESetup1 : LastAdaptiveFreq='11.42219GHz' Phase='0deg'
X-band 1C-SW-A3.75-T2.6 Triple Choke Structure-Cu
A.D Yeremian, 3 May 2010
Electric field
Magnetic Fields Hmax = 560KA/m = 5.6KA/cmHmax@b = 510KA/m = 5.1KA/cmH@top = 40 A/m = 0.4A/cm
X-band 1C-SW-A3.75-T2.6 Triple Choke Cu, Fields Normalized to 10MW RF Losses
Emax@iris = 320 MV/mE@top = 37 KV/m
A.D Yeremian, 3 May 2010
X Band Full Choke Structure 1C-SW-A3.75-T2.6 View Port-Cu
Solid model by David Martin
A.D Yeremian, 3 May 2010
ChokeR = 4 mm
25 m
m
15 o
12.7mm
1C-SW-A3.75-T2.6-Full Choke View Port-Cu
f = 11.4216 GHzQo = 12416Qe = 11938
35.4
mm
A.D Yeremian, 3 May 2010
-0.2 0 0.2 0.4 0.6 0.8 1 1.2
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
F = 11.42216Band width = 400KHzS11= -30.5dBQo = 12416Qe = 11938Coupling = 1.07
1C-SW-A3.75-T2.6-Choke View Port-Cu
400 KHz
Electric Field Magnetic Field
f Emax(Iris) Hmax(Iris) Emax(ch) Hmax(ch) (GHz) (MV/m) (kA/m) (KV/m) (A/m)
At location Iris Iris/cell VPbase/@VP VPbase/@VP 11.4228 350 200/580 50/28 300/200
1C-SW-A3.75-T2.6-Full Choke View Port-Cu, Fields Normalized to 10MW RF Losses
A.D Yeremian, 3 May 2010
A.D Yeremian, 3 May 2010
Magnetic FieldElectric Field
f Emax(Iris) Hmax(Iris) Emax(ch) Hmax(ch) (GHz) (MV/m) (kA/m) (KV/m) (A/m)
At location Iris Iris/cell VPbase/@VP VPbase/@VP 11.4228 350 200/580 50/28 300/200
1C-SW-A3.75-T2.6-Full Choke View Port-Cu, Fields Normalized to 10MW RF Losses
A.D Yeremian, 3 May 2010
Summary
X Band Choke Structures
• SLAC has built the choke flanges to test a Cesic structure.
• KEK and Frascati are building the triple choke structures.
• SLAC are building the full choke structure with a view port.