Multi-stage pulse compressor Ping Wang, Igor Syratchev, Jiaru Shi, Hao Zha CLIC Workshop， 18-22 January 2016

Design of the X-band Multi-stage pulse compressor Outline Background Design of the X-band Multi-stage pulse compressor PM-AM modulation for perfect flat-top pulse Summary CLIC Workshop， 18-22 January 2016

Linacs and RF sources CLIC X-band accelerator SACLA C-band accelerator (8.5GeV) Pulse length : 500ns Total pulse length : 242ns Peak input power: 61.3MW Peak input power: 73MW SPring-8 Angstrom compact free-electron laser RF sources The peak power of commercial RF sources are limited. Frequency (GHz) Power (MW) Pulse length (us) SACLA 5.712 50 2.5 CLIC 11.994 1.5 It is usually easier to build RF sources with low peak power and long pulse length. 2010-CERN-Grudiev, A.; Wuensch, W. - DESIGN OF THE CLIC MAIN LINAC ACCELERATING STRUCTURE FOR CLIC CONCEPTUAL DESIGN REPORT 2014-PRST-T.Inagaki-High-gradient C-band linac for a compact x-ray free-electron laser facility

Pulse compression Passive pulse compressor Pulse need by linacs Pulse from RF sources Pulse compressor Passive pulse compressor Energy storage Energy release The phase/amplitude modulation to the RF power source. The properties of the RF storage network (coupling/phase) can be controlled externally. Passive compressors usually require rapid phase modulation within the incident pulse Active pulse compressor Active compressors contain elements with time-dependent electrodynamic parameters. (plasma switch, electron-beam triggered switch)

Pulse compressors Pulse compressors with resonant cavity A method of doubling SLAC’s energy BOC RF pulse compressor Super-compact SLED Pulse compressors with long delay line Input pulse RF source 3dB hybrid Delay line SLED-II Resonance Delay Lines

Design of the X-band Multi-stage pulse compressor Outline Background Design of the X-band Multi-stage pulse compressor PM-AM modulation for perfect flat-top pulse Summary CLIC Workshop， 18-22 January 2016

Output of SLED-type compressor Input power Output power Q0 = 1.77x105 , β = 5.98 Peak Power Gain : 6 ＋ － SLED transmission spectrum The input pulse can be considered as two parts

Methods to obtain flat-top pulse SLED Phase modulation Power Gain : 2.8 Efficiency: 47% Amplitude modulation SLED-II 2 x 41.5 m,  77 mm Port 1 3dB hybrid Long delay line Port 2 The output pulse of SLED-II Power Gain : 4.1 Efficiency: 68% SLEDII transmission spectrum

Multi-stage X-band pulse compressor QS0 = 1.77x105, βS = 5.98 QC0 = 4x104, βC = 1.4 Power after correction cavities f1/T compressed T compressed Average Power Gain : 3.68 The spectrum of the system Efficiency: 61% 1992- S. Kazakov -Pulse Shape Correction for RF Pulse Compression System

Storage cavity (2013) Cavity operating mode H0,1,32 , Q0 (Measured) = 1.77x105, β (Measured)=5.98 77 mm 444 mm Compact mode launcher 3dB hybrid Resonant cavity

Correction cavities Cavity operation mode TE012 r θ φ 251.7 mm 74.9 mm Small coupling Cavity a=32.26mm Frequency/GHz S21/dB Dual-mode circular polarizer

Circular polarizer dB Frequency/GHz Port1（Mode 1） Port3（Mode 3， Mode 4） Port2（Mode 2） Mode 3 Mode 4 Frequency/GHz dB Mode1 and mode2 are isolated 2014-SLAC-Wang Juwen-Advances in RF Deflector and Pulse Compression System

The full design 170 mm 266 mm 251.7 mm f 444 mm QC0 = 4x104 βC = 1.4 QS0 = 1.77x105 βS = 5.98

Design of the X-band Multi-stage pulse compressor Outline Background Design of the X-band Multi-stage pulse compressor PM-AM modulation for perfect flat-top pulse Summary CLIC Workshop， 18-22 January 2016

ej(pi/2+θ) ej(0-θ) θ /Degree PM-AM modulation CLIC power supply system PM-AM principle Normalized output Power Phase/Degree θ /Degree Klystron 1 Klystron 2 Hybrid 1 Load 1 Load 2 Hybrid 2 Pin Compressor 1 Compressor 2 Pout Linac 1—10 CLIC power supply system based on klystrons

PM-AM modulation Relative size t/ns Relative size t/ns Compression ratio Input Power Output power:425MW Input Power:102MW Power Gain: 4.18 Power Gain Efficiency Efficiency:0.46 Compression ratio

Summary We have designed a new type of pulse compressor We propose a layout of the power supply system with PM-AM modulation

Thanks for your attention ! CLIC Workshop， 18-22 January 2016 Wang Ping/ BE.RF

Appendix(For page 8) No correction cavity 2 correction cavities

Appendix(For page 16) Compensation of the transient beam loading A linear ramp of the input rf amplitude has been applied to compensate the bunch-to-bunch energy variation to first order. 2011-A. Lunin-PRST-Analytical solutions for transient and steady state beam loading in arbitrary traveling wave accelerating structures