Planned Breakdown Test of SW Accelerator Cavity with Shaped Iris
J.M Neilson, V. Dolgashev and S. Tantawi
SLAC National Accelerator Laboratory
IWLC 2010Geneva
Outline
• Previous breakdown results for elliptical and rounded iris
• Calculations for shaped iris geometry
Two Single-Cell-SW Structures with same magnetic but different electric fields
Thick elliptical iris
Thin round iris
1C-SW-A3.75-T1.66-Cu 1C-SW-A3.75-T2.0-Cu
Thin round irisThick elliptical iris
Parameter Values for Simple Iris(Field Normalized for 100MeV/m Gradient)
Parameter T=1.66 Round Iris
T=2.6mmElliptical
Iris
Stored Energy [J] 0.189 0.189
Q-value 8820 8560
Shunt Impedance [MOhm/m] 85.2 82.6
Max. Mag. Field [KA/m] 314 325
Max. Electric Field [MV/m] 266 203
Losses in one cell [MW] 1.54 1.59
Hmax*Z0/Eacc 1.18 1.22
Max. Im{E x H*} W/µm2 42.8 44.4
Max. Im{E x H*}/H2 417 407
Breakdown Dependence
8 0 1 0 0 1 2 0 1 4 0 1 6 0 1 8 0 2 0 0 2 2 01 0 7
1 0 6
1 0 5
1 0 4
1 0 3
1 0 2
1 0 1
1 0 0
G rad ien t M V m Bre
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a 0.215, t 4.6mm , K EK 4a 0.143, t 2.6mm , SLA C 1a 0.105, t 2.0mm , SLA C 1
0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 01 0 7
1 0 6
1 0 5
1 0 4
1 0 3
1 0 2
1 0 1
1 0 0
P eak Elec tr ic F ield M V m Bre
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a 0.215, t 4.6mm, K EK 4a 0.143, t 2.6mm, SLA C 1a 0.105, t 2.0mm, SLA C 1
0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 01 0 7
1 0 6
1 0 5
1 0 4
1 0 3
1 0 2
1 0 1
1 0 0
P eak M ag n etic F ield k A m Bre
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a 0.215, t 4.6mm , K EK 4a 0.143, t 2.6mm , SLA C 1a 0.105, t 2.0mm , SLA C 1
2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 01 0 7
1 0 6
1 0 5
1 0 4
1 0 3
1 0 2
1 0 1
1 0 0
P eak P u ls e Heatin g d eg . CBre
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bilit
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a 0.215, t 4.6mm , K EK 4a 0.143, t 2.6mm , SLA C 1a 0.105, t 2.0mm , SLA C 1
0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 01 0 7
1 0 6
1 0 5
1 0 4
1 0 3
1 0 2
1 0 1
1 0 0
P eak Elec tr ic F ield M V m Bre
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a 0.143, t 1.66mm , K EK 1a 0.215, t 4.6mm , K EK 4a 0.143, t 2.6mm , SLA C 1a 0.105, t 2.0mm , SLA C 1
0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 01 0 7
1 0 6
1 0 5
1 0 4
1 0 3
1 0 2
1 0 1
1 0 0
P eak M ag n etic F ield k A m Bre
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y1pulsemeter a 0.143, t 1.66mm , K EK 1
a 0.215, t 4.6mm , K EK 4a 0.143, t 2.6mm , SLA C 1a 0.105, t 2.0mm , SLA C 1
2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 01 0 7
1 0 6
1 0 5
1 0 4
1 0 3
1 0 2
1 0 1
1 0 0
P eak P u ls e Heatin g d eg . CBre
akd
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nPro
bab
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y1pulsem
eter
a 0.143, t 1.66mm , K EK 1a 0.215, t 4.6mm , K EK 4a 0.143, t 2.6mm , SLA C 1a 0.105, t 2.0mm , SLA C 1
8 0 1 0 0 1 2 0 1 4 0 1 6 0 1 8 0 2 0 0 2 2 01 0 7
1 0 6
1 0 5
1 0 4
1 0 3
1 0 2
1 0 1
1 0 0
G rad ien t M V m Bre
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nPro
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a 0.143, t 1.66mm , K EK 1a 0.215, t 4.6mm , K EK 4a 0.143, t 2.6mm , SLA C 1a 0.105, t 2.0mm , SLA C 1
thin round iris
thick elliptical iris
thin round iris
thick elliptical iris
1C-SW-A3.75-T2.6-Cu 10 MW input
Resonance at 11.4212 GHz β = 0.988
Maximum magnetic field 672 kA/m Maximum magnetic field 390 MV/m
V.A. Dolgashev, 25 September 2007
1C-SW-A3.75-T2.2-Cu 10 MW input
Resonance at 11.424 GHz β = 1.007
Shaped Iris
Thick elliptical iris Thin round iris
- Iris profile designed to maximize shunt impedance, minimize peak surface magnetic field
Parameter T=1.66 Round Iris
T=2.6mmElliptical
IrisT=2.2mm
Shaped Iris
Stored Energy [J] 0.189 0.189 0.186
Q-value 8820 8560 10090
Shunt Impedance [MOhm/m] 85.2 82.6 99.2
Max. Mag. Field [KA/m] 314 325 294
Max. Electric Field [MV/m] 266 203 268
Losses in one cell [MW] 1.54 1.59 1.32
Hmax*Z0/Eacc 1.18 1.22 1.11
Max. Im{E x H*} W/µm2 42.8 44.4 56.5
Max. Im{E x H*}/H2 417 407 650
SW Cells a/λ =0.143, π Phase ShiftField Normalized for 100MeV/m Acceleration
Summary
• New structure designed with lower magnetic field
• However local Poynting vector significantly increased compared to other structure