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Ursula van Rienen, Universität Rostock, FB Elektrotechnik und Informationstechnik, AG Computational Electrodynamics
Scattering Parameter Calculationfor the 2x7 Superstructure
TESLA Collaboration Meeting
INFN Frascati May 26-28, 2003
Karsten Rothemund, Dirk Hecht, Ulla van Rienen
Ursula van Rienen, Universität Rostock, FB Elektrotechnik und Informationstechnik, AG Computational Electrodynamics
2x7-Superstructure
-e
7 Cell TESLA Cavity
HOM-Coupler
Input-Coupler
Images: I.Ibendorf
Radius Adapter
Ursula van Rienen, Universität Rostock, FB Elektrotechnik und Informationstechnik, AG Computational Electrodynamics
2x7-Superstructure
-e
Images: I.Ibendorf
Rotation(couplers)
Shift of reference planes(MAFIA simulation has tubes on both sides)
Ursula van Rienen, Universität Rostock, FB Elektrotechnik und Informationstechnik, AG Computational Electrodynamics
Radius Adaptor
57 mm39 mm
f = 1.5 – 3.0 GHz:TE11co
TM01co
TE21co
f =1.54106GHz
f =2.01317GHz
f =2.55643GHz
TTF beam pipe superstructure
TE11 (deg.) TM01 TE21 (deg.)
Ursula van Rienen, Universität Rostock, FB Elektrotechnik und Informationstechnik, AG Computational Electrodynamics
HOM-Input-Coupler
antenna cone shape as in9 cell HOM coupler(no data available in drawing)
Geometry data taken from drawing „Formteil F“ (3 99 9177/D.001),[1]
[1] coutesy DESY
Ursula van Rienen, Universität Rostock, FB Elektrotechnik und Informationstechnik, AG Computational Electrodynamics
HOM-Coupler (HOM 2 + HOM 3)
HOM 2
HOM 2HOM 3 HOM 1
Input
rotate
HOM 3
shift planes
27.4 mm27.4 mm
Ursula van Rienen, Universität Rostock, FB Elektrotechnik und Informationstechnik, AG Computational Electrodynamics
7 Cell TESLA Cavity
f=1.5-3.0 GHz
TE11
TM01
TE21
Plot: MWS, simulation: MAFIA, 2D, time domain
f/GHz
|S..|/dB
f/GHz
|S..|/dB |S..|/dB
Ursula van Rienen, Universität Rostock, FB Elektrotechnik und Informationstechnik, AG Computational Electrodynamics
Analytical Sections
Rotation between HOM-Couplers• Rotate reference frame of dipole and quadrupole modes• length of section is 0
Wave Guide (neg. and pos.)• shift reference plane of cavity• shift HOM 3 to correct position
Ursula van Rienen, Universität Rostock, FB Elektrotechnik und Informationstechnik, AG Computational Electrodynamics
Subsections
Subsection Port-Modes # of this typeHOM-Input-coupler 5 + 5 + 1+1 1HOM coupler 2 + 3 5 + 5 + 1 2TESLA cavity 5 + 5 2Plane shift cavity 5 + 5 4Shift of HOM 3 5 + 5 2Rotation 5 + 5 4Radius adaptor 5 + 5 2
Total number of subsections: 17Total number of modes = S-matrix dimension: 174(to be computed for each frequency point)
Ursula van Rienen, Universität Rostock, FB Elektrotechnik und Informationstechnik, AG Computational Electrodynamics
CSC-Computation
Calculation of overall S-matrixopen ports: beam pipe, 3x HOM-, 1x Input-coupler
1500 values computed in 1.5-3 GHz frequency range shown here: 2.46-2.58 GHz (3rd dipole passband)
481 frequency-points + interpolation
S-valuesof 7-cell cavity
f/GHz
|S..|/dB
Ursula van Rienen, Universität Rostock, FB Elektrotechnik und Informationstechnik, AG Computational Electrodynamics
Results
Coupling between HOM1 and HOM2 to beam pipe modes
HOM1
HOM2
downstream beam pipe
upstream beam pipe
f/GHz
|S..|/dB
f/GHz
|S..|/dB
Ursula van Rienen, Universität Rostock, FB Elektrotechnik und Informationstechnik, AG Computational Electrodynamics
Results
Coupling between HOM couplers
Coupling between Input-coupler and beam pipe modes
f/GHz
|S..|/dB
f/GHz
|S..|/dB
Ursula van Rienen, Universität Rostock, FB Elektrotechnik und Informationstechnik, AG Computational Electrodynamics
Timing S-Parameter
CST-MicrowaveStudioTM (2.4 GHz Pentium 4, 4GB RAM):• HOM-Input-Coupler:
316,160 mesh points (20 lines/lambda),5 beam pipe modes + 2 koaxial modesTotal computation time: 100 h (12 runs)
• HOM-Coupler:178,920 mesh points (20 lines/lambda),5 beampipe modes + 1 koaxial modeTotal computation time: 24 h (11 runs)
MAFIA (SUN Enterprise, 400 MHz, 4GB RAM):• TESLA 7 cell cavity:
2D-geometry (rz)31,158 mesh pointsTotal computation time: 2h + 6.5h + 6.75h
Ursula van Rienen, Universität Rostock, FB Elektrotechnik und Informationstechnik, AG Computational Electrodynamics
Timing CSC
CSC: platform: Mathematica 4.117 subsections 5 modes in structuredimension of matrix: 174481 frequency points, 2.46 – 2.58 GHz430 s on Pentium 3 (1 GHz, 512 MB RAM)
Ursula van Rienen, Universität Rostock, FB Elektrotechnik und Informationstechnik, AG Computational Electrodynamics
Summary
• S-parameter of 2x7 TESLA-Superstructure have been calculated (an open structure) with CSC• 5 modes have been considered in the structure• S-parameter of subsections were computed with
• CST-MicrowaveStudioTM (coupler sections, 3D)• MAFIA (TESLA cavity, 2D-rz-geometry)• analytically (shifting planes, rotation)
• some exemplary coupling parameters have been presented• computation times for S-parameters of subsections in order of days• additional computation times whole structure then in the order of minutes• parameter tuning (e.g. rotation angles, distances) possible