CTF3-PETS and waveguide networks,

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CTF3-PETS and waveguide networks, limitations and
scenarios. I. Syratchev
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CTF3 PETS upgrade in 2006

• Improvements
• The new slotted technology improves vacuum
  conductivity and cooling efficiency.
• The transverse HOM damping for free.
• The new re-optimized coupler (directly to the
  square waveguide, no stainless steel). Losses
  reduced from 2.4 to 0.7
• No tuning, the RF design finalized to a micron
  level.
• Structure fits into existing vacuum tank.
• The 66 GHz problem have been resolved.
• The first application of the CLIC PETS technology.

9 mm
6.7 mm
Power production curve
115 MW 164 MW
5 A 6 A
MW
Distance, m
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Transverse HOM in 9mm structure. Gdfidl
Wake for original 9 mm CTF3 PETS in red, for the
new version in blue.
Wt, V/pC/m/mm
Distance, m
Frequency, GHz
Wt, V/pC/m/mm
Distance, m
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Structures phasing
10x550
F1-137.90
3.332x10
F2-97.70
F3-138.20
(F1- F3)/2 0.150
(F1- F2)/2 20.10
2.325
20.10 phase delay circuit
1.45
R 0.3
R 5.0
R 5.52
5
66 GHz
Parameters F 65.887 GHz Beta0.0117
C Fs2.99855x2265.968 GHz
Field build up
distance
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New waveguide standard
Moving from rectangular waveguide WR34 to the
waveguide with square cross-section (8.64x8.64)
allows to increase vacuum conductivity, reduce
ohmic losses and electric field on a surface.
Example

• Losses per meter.
• copper, theoretical
• Wr28 13.7
• Wr34 9.0
• square 8.64 5.7
• square 9.5 4.6

Transfer line
WR34
WR34
WR28
Coupler
Total 1 m (WR34) 0.15 m (WR28)
Efficiency 0.976x0.9x0.86x0.978x0.9650.713
Efficiency 0.997x0.943x0.86x0.9860.797 12
Replacing coupler and waveguides
Directional couplers
All ready for brazing
All the new RF components
Hybrids
H,E multipurpose bends
Straight sections and tapers
New attenuator (to be ready in April 2006)
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The RF/vacuum valve was installed in CTF2
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Possible PETS upgrade towards higher power

• The low loss transfer line is build of the
  waveguide sections each 50 cm long. We can
  discuss the possible lengthening of the CTF3 PETS
  by the same amount. The two cases were
  considered
• To build extra 9 mm section 46 cm (140 cells)
  long.
• To lengthen each of the three original structures
  by 16.7 cm (13050 cells).

I5A, F21
MW
MW
176 MW
200 MW
Distance, m
Distance, m
MV/m
MV/m
Distance, m
Distance, m
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Long pulse and pulse compressor
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Effect of switching time
50 ns switching
Ideal
60 ns delay
60 ns delay
Tp360 ns
Tp360 ns
RTL0.03
100 ns delay
In general for non-zero phase flip, the system
should be modified as follows Delay time
T(line) (flat top needed) T (phase
switch) Input pulse T(CTF3) T (line) x
Compression chosen.
Tp720 ns
RTL0.06
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Active high power phase switch
Si disk tested at high power 30 GHz in JINR in
2006
Manipulation of the RF phase (0 -1800) at a
constant power level
Basic element 2-port overmoded miter bend
Silicon
Basic principle irradiating the Si wafer surface
one can change the length of the pass way for RF,
resulting in any given phase advance
corresponding to wafer thickness.
Quartz
It is believed, that the flash over on the
ceramic surface was caused by the residual
electrons coming from the FEM collector. The
improved test set-up is under discussion.
The first laser tests in IAP in 2005 confirmed
the validity of this approach.