5th Collaboration Meeting on X-band Accelerator Structure Design and Test Program. May 2011 Review of waveguide components development for CLIC I. Syratchev, CERN

5th Collaboration Meeting on X-band Accelerator Structure Design and Test Program. May 2011 Many hundred thousands of waveguide components are needed for CLIC. The fabrication cost and waveguide network logistic are serious issues that are needed to be addressed to make an optimal RF waveguide distribution system. The RF network in CLIC connects at a short distance (~ 0.5 m) broadband decelerating structure (PETS) and narrowband accelerating structure. Thus, all the waveguide components should be optimised to avoid parasitic circulation of the reflected signals in a system. We have developed the special RF components to provide specific to CLIC operational properties. In general, the particular choice of individual components could seriously affect the RF network layout and cost.

5th Collaboration Meeting on X-band Accelerator Structure Design and Test Program. May 2011 ON/OFF mechanism CLIC module RF network 3 dB splitter

5th Collaboration Meeting on X-band Accelerator Structure Design and Test Program. May GHz choke mode flange prototype has been tested at SLAC up to 90 MW 200 ns. To allow the independent transverse alignment of the two linacs in CLIC, the special, contact-free choke mode flanges are planned to be used. By specification, the 0.25 mm transverse misalignment should be tolerated. y x Throughout the design, reflection and matched radiation through the choke were minimized In this geometry shift along narrow wall of the waveguide causes severe coupling to the trapped TM 02 mode, which is close to the operating frequency.  y ±0.25mm  y ±0.5mm Choke flange with circular groove choke Matched radiation Reflection S-parameters, dB

5th Collaboration Meeting on X-band Accelerator Structure Design and Test Program. May 2011 Modified, double-sector choke flange Frequency, GHz S11, dB y x  y ±0.5mm  x ±0.5mm The new geometry allows for ±0.5mm sheer shift in both directions. It also can tolerate twist <1 0 and kink < 3 0. Matched radiation through the choke is below -40 dB. The slot is 2.5 mm wide.

5th Collaboration Meeting on X-band Accelerator Structure Design and Test Program. May Ready to be used as a part of the compact RF/vacuum valve. - Building block of the RF phase stable long waveguide line. It will naturally compensate the thermal expansion without introducing extra RF phase advance. - Rotatable (360 0 ) high RF power waveguide contact free joint (with circular grove). Designed for C-band medical accelerator. Polarizer converts H 10 in rectangular WG into rotating H 11 in a circular WG Choke flange Choke flange. Other applications Mini UHV gate valve

5th Collaboration Meeting on X-band Accelerator Structure Design and Test Program. May dB H-plane splitter The GHz version of the splitter was tested at SLAC up to 150 MW x 260 ns. Compact vacuum pumping port (design) S11, dB Radiation into the vacuum port S-parameters, dB

5th Collaboration Meeting on X-band Accelerator Structure Design and Test Program. May 2011 S11,S12 S13,S14 3 dB hybrids (WR90) CLIC choice. 32 MV/m surface E-field at 100 MW. H-plane#1 H-plane#2 E-plane SLAC-type KEK-type

5th Collaboration Meeting on X-band Accelerator Structure Design and Test Program. May 2011 Cross Potent family H-plane E-plane Hybrid solution

5th Collaboration Meeting on X-band Accelerator Structure Design and Test Program. May 2011 Reflected Transmitted Stroke 7.7 mm RF power, dB Piston position (gap width), mm ON OFF Compact design of the high RF power variable (mechanically) reflector Radiation through the chokes The variable reflector is a core element of the PETS ON/OFF mechanism. It is activated when the local termination of the RF power production in PETS is required. S-parameters, dB

5th Collaboration Meeting on X-band Accelerator Structure Design and Test Program. May 2011 Influence of the external waveguide circuit bandwidth on the PETS RF power production Variable reflector with compact H 20 -> H 01 mode convertor Phase, deg. Amplitude PETS output signal Amplitude Phase, deg. Time, ns

5th Collaboration Meeting on X-band Accelerator Structure Design and Test Program. May 2011 PETS ON/OFF operation Power to the structure Power extracted from the drive beam The simulations have been done with HFSS, when the discrete current elements were representing the steady state current at a fixed frequency. ON OFF

5th Collaboration Meeting on X-band Accelerator Structure Design and Test Program. May 2011 High RF power variable reflector. Other applications Variable attenuator (phase shifter) Variable splitter Load (short circuit)

5th Collaboration Meeting on X-band Accelerator Structure Design and Test Program. May 2011 X-band moderate peak power ‘dry’ RF load with SiC absorber (design). The 15 MW peak RF power loads are the most common components in CLIC module. ~ loads will be needed for 3 TeV CLIC option. 100 mm Max. E-fields on the ceramic surface tangential normal 15 MW SiC

5th Collaboration Meeting on X-band Accelerator Structure Design and Test Program. May 2011 X-band high peak power (>50 MW) broadband ‘dry’ stainless steel load. Pulsed heating distributions along the load: H-field plot (quarter of the period) Design specifics Load regular part cross section E The load half Matching taper WR90 We have received about 50 loads. The companies provide very reproducible results with reflection <-30dB at frequencies above GHz. The loads have been tested up to 60MWx400ns (KEK) and 25MWx1600ns (SLAC). Loads #36-39 Green – design Red - measured