Manipulating RF phase and amplitude at high power level. Past, present and future. I. Syratchev

Generic RF power manipulating circuits Variable phase shifter L Exp(j0) Variable power splitter Movable short circuit L Exp(j0) 3dB hybrid 0->1 Exp(j(0+Lx/) 1->0 Exp(j0+/2) Exp(j(0+Lx/) ‘Classical’ movable short circuits. Do not work at high RF power! Design of ‘RF contact-free’ movable short circuit is the main challenge.

Year 2008. Designed and fabricated by GYCOM (Russia) Splitter measurements Variable (2) RF phase shifter 3-dB hybrid Variable RF power splitter H10-H01 mode converter Short circuit part Both devices operated at high power level in TBTS until late 2010. However, 10% insertion losses, narrow bandwidth and complicated design (fabrication cost) never made us satisfied.

Mode converter build by CEA piston Year 2009. First compact high power movable short circuit design (Syratchev/Cappelletti) Compact H10□-> H20 □ ->H01 12 GHz mode convertor (original idea by S. Kazakov, KEK in 2003) E-field H-field H01 H20□ H10□ Mode converter build by CEA piston The use of the compact mode converter allowed to reduce dramatically the length of device. However bandwidth was still narrow to be compatible with CLIC PETS ON/OFF needs.

extremely broad band (~1 GHz) Year 2010. Ultra compact high power movable short circuit and variable reflector designs (Syratchev). Full reflection Full transmission RF filter Radiation through the filter extremely broad band (~1 GHz) low surface electric field (< 45 MV/m at 150 MW) reduced actuators stroke (~l/4) contact-free

The variable RF short circuit The variable RF reflector and short circuit. OFF The variable RF short circuit Reflection Transmission Bold line – measured Thin line -HFSS ON

Modification of the TBTS PETS tank layout in 2011. The movable compact RF short circuit was successfully tested in TBTS at power levels well above 150 MW.

Year 2013. 3dB ‘cross’ hybrid. 3 ports; 4 modes Inspired by the work done by: Year 2013. 3dB ‘cross’ hybrid. 3 ports; 4 modes Transmission C. Chang, S. Tantawi SLAC Reflection S. Kazakov, KEK Rotating TE11 A1 A2

450 Magic-T A1/20.5 x e(j) A1/20.5 A1/20.5 x e(j0) A1/20.5

Rotating modes launcher. Practical design. Reflection Transmission Ultra compact 3dB hybrid design by A. Grudiev

Variable splitter #1->#2 #1->#3 #1 #2 #4 #3

To come in year 2014. Most compact variable splitter (personal choice) Most compact design. Components (not a hybrid yet) high power tested. We have enough experience with operating the system with two independent pistons.

Where would we need them? XBOX 1,2 layout before Where would we need them? RF load klystron Pulse compressor They will allow to process two structure in parallel in the most convenient way, when each of the structure will receive personal RF power handling They could operate as a part of processing procedure (in the case of the structure breakdown), thus minimising transient thermal load in the pulse compressor. XBOX 1,2 layout after Variable splitters Anticipating final testing capability of 8 structures (XBOX #1,2,3), 8 power splitters will be needed It will be also useful to replace the old GYCOM devices in CLEX, then 2 more splitters are needed. With 1-2 spare, we should plan to fabricate ~ 12 such device.

Dynamic symulations results by MMT Stay tuned. Fast (<20 ms) actuators are under development in RF/PM section Two vacuum compatible prototypes are at CERN. The RF network is in preparation. Dynamic symulations results by MMT