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CLIC Main linac structure and Crab cavity. Vasim Khan. 28.08.09. In order to damp the LOM & SOM the cut-off frequency of the manifold should be below 8.0 GHz which is the lowest mode in the cavity. Circular wave-guide. Rectangular wave-guide. TE 11 mode Fc= 7.63 GHz @ b= 11.5 mm.
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CLICMain linac structure and Crab cavity Vasim Khan 28.08.09
In order to damp the LOM & SOM the cut-off frequency of the manifold should be below 8.0 GHz which is the lowest mode in the cavity. Circular wave-guide Rectangular wave-guide TE11 mode Fc= 7.63 GHz @ b= 11.5 mm TM11 mode Fc= 7.62 GHz @ a = 30 x 26 mm x mm To damp the HOMs the cut-off frequency of the manifold should be above 12 GHz TM11 mode Fc= 13.6 GHz @ 17 x 15 mm x mm TE11 mode Fc= 13 GHz @ b = 6.75 mm TEmn TMmn
TM01 Fundamental mode 8.0 GHz TM11 Dipole (SOM) mode 12.0 GHz TM11 TE11
Blue : H-H boundary condition Red : E-H boundary condition
H-field E-field 90 deg. 1st mode 8.56 GHz TM01 H-B.C. 163 deg. 2nd mode 15.56 GHz H-B.C. 180 deg. 3rd mode 18.66 GHz First 5 modes @ 120 deg.
H-field E-field 120 deg. 1st mode 11.98 GHz TM11 180 deg. 2nd mode 18.65 GHz TM11 E-B.C. H-B.C. 180 deg. 3rd mode 18.68 GHz TE11 First 5 modes @ 120 deg.
Simulation with SiC SiC H-E B.C. H-H B.C. E-H B.C.
Simulation with SiC SiC E-H B.C. H-E B.C.
Large coupling & no SiC H-field E-field Mode 1 Mode 1 H-B.C. Mode 2 Mode 2 H-B.C. Mode 3 Mode 3
Large coupling & no SiC H-field E-field Mode 1 Mode 1 E-B.C. Mode 2 Mode 2 H-B.C. Mode 3 Mode 3
Large coupling & no SiC H-field E-field Mode 1 Mode 1 H-B.C. Mode 2 Mode 2 E-B.C. Mode 3 Mode 3
Monopole mode Cell # 1 Cell # 1 Cell # 21 Cell # 21
Cell # 1 Cell # 1 Kick-factor calculations Cell # 5 Cell # 5 Cell # 13 Cell # 13 Cell # 24 Cell # 24
Kick factor calculations ?? Monopole : Dipole : Does it depend on the group velocity? i.e. Whether it is negative or positive ?
Next ?? • More simulations for the Crab cavity to optimise the dimensions, study dispersion curves. • Simulations incorporating both circular manifolds • Verification of kick-factor calculations (Bane & Gluckstern paper) • CLIC_DDS : Simulations to verify the prediction of the fits • Background reading for corrections in chapter #1 and necessary corrections. Issue(s) My passport has arrived in Manchester today....I assume I got visa, need to check this evening. For extending visa, I need to know the process!