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

2. 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， January 2016

3. 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

4. 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)

5. 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

6. 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， January 2016

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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

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

14. 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， January 2016

15. 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

16. 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

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

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

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

20. 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