CLIC meeting

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I.Syratchev
Simulation of the full-size PETS with
GDFIDL. Data from W.Bruns. Part II.
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Simulation of the full-size PETS with GDFIDL
20 cell with output couplers
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Simulation of the full-size PETS with GDFIDL
Dipole WII envelopes (normalized)
Impedances (log. scale)
No SiC
With SiC
Distance, m
Frequency, Hz
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Simulation of the full-size PETS with GDFIDL
Impedances windowed around 30 GHz
1. The picks that are observed above 30 GHz
were not identified with HFSS simulations. They
bring the strongest contribution to the wake
about-30-GHz-component after 1 meter.
?
Frequency, Hz
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Simulation of the full-size PETS with GDFIDL
The 30 GHz component decay via initial position
of the running window.
1 meter running Fourier window around 12 and 30
GHz
Impedance
Distance, m
Frequency, GHz
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Simulation of the full-size PETS with GDFIDL
Discussion 1. The 30 GHz component has
extremely strong decay (see left picture). 2.
But there is no difference between lossy and
un-lossy cases. This could be because of the very
fast extraction of the dipole mode through the
wave-guides (Vgr70). From the specter the,
equivalent Q-factor (external) is about 15. For
verification of that effect the much longer
structure (100 /or more? cells) has to be
simulated. 3.Do we sure that GDFIDL compute
losses properly. I think YES. 4. The around 12
GHz trapped modes are also clearly seen. 5.The
above 30 GHz modes for me does not looks like
numerical noise, but the origin of that spikes is
not clear at all for a moment. (Compare to my
previous presentation, where we do not see them).
Could be these are the modes of the coupler,
which length is rather compatible now with a 20
cell length structure.
Residual specter calculations
Window
0 - 10 m
Amplitude
0.5 - 10 m
Frequency, GHz
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Simulation of the full-size PETS with GDFIDL
Next step 1. If possible, to increase the
structure length as much as reasonable. 2. To
continue the slots with the SiC box further more
, until the beam sees corrugated wave-guide. This
could help to damp the modes that
recently appeared around 30 GHz.