Post on 15-Jan-2016
transcript
CLICCLICMain linac structure and Crab cavityMain linac structure and Crab cavity
Vasim KhanVasim 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.
b π2
p cf mn
c 22
c b
n π
a
πm
π2
cf
Circular wave-guideRectangular wave-guide
TE11 modeFc= 7.63 GHz @ b= 11.5 mm
TM11 modeFc= 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
TE11 modeFc= 13 GHz @ b = 6.75 mm
TM11 modeFc= 13.6 GHz @ 17 x 15 mm x mm
TMmn TEmn
TM01
Fundamental mode 8.0 GHz TM11
Dipole (SOM) mode 12.0 GHz
TM11 TE11
Crab cavity profile
Blue : H-H boundary conditionRed : E-H boundary condition
90 deg.1st mode8.56 GHzTM01
180 deg.3rd mode18.66 GHz
163 deg.2nd mode15.56 GHz
First 5 modes @ 120 deg.
H-B.C.
H-B.C.
E-field H-field
120 deg.1st mode11.98 GHzTM11
180 deg.2nd mode18.65 GHzTM11
180 deg.3rd mode18.68 GHzTE11
First 5 modes @ 120 deg.
H-B.C.
E-B.C.
E-field H-field
H-H B.C. E-H B.C. H-E B.C.
10ε r 0.3tanδ 1μ r
SiC
Simulation with SiC
10ε r 0.3tanδ 1μ r
SiC
E-H B.C. H-E B.C.
Simulation with SiC
Large coupling & no SiC
H-B.C.
H-B.C.
Mode 1
Mode 2
Mode 3
Mode 1
Mode 2
Mode 3
E-field H-field
H-B.C.
E-B.C.
Mode 1
Mode 2
Mode 3
Mode 1
Mode 2
Mode 3
Large coupling & no SiCE-field H-field
E-B.C.
H-B.C.
Mode 1
Mode 2
Mode 3
Mode 1
Mode 2
Mode 3
Large coupling & no SiC
E-field H-field
dze EVL
0
ωtzz
dze EVL
0
ωtzz
Cell # 21Cell # 21
dze EVL
0
ωtzz dze EV
L
0
ωtzz
Cell # 1 Cell # 1
Monopole mode
Cell # 1
Cell # 5
Cell # 13
Cell # 24
Cell # 1
Cell # 5
Cell # 13
Cell # 24
dze EVL
0
ωtzz
dze EVL
0
ωtzz
Kick-factor calculations
Kick factor calculations ??
Monopole : dze EVL
0
ωtzz
Dipole :
3.5a dze E
3.5a dze EV
L
0
ωtz
L
0
ωtzz
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!