Multi-stage pulse compressor
Ping Wang, Igor Syratchev, Jiaru Shi, Hao Zha
CLIC Workshop， 18-22 January 2016
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
Total pulse length : 242ns
 SACLA C-band accelerator (8.5GeV)
Pulse length : 500ns
Peak input power: 73MW
Peak input power: 61.3MW
 RF sources
•
The peak power of commercial RF
sources are limited.
•
It is usually easier to build RF sources
with low peak power and long pulse
length.
SPring-8 Angstrom compact free-electron laser
Frequency
(GHz)
Power
(MW)
Pulse length
(us)
SACLA
5.712
50
2.5
CLIC
11.994
50
1.5
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
Pulse from RF sources
Pulse compressor
Pulse need by linacs
 Passive pulse compressor
The phase/amplitude modulation
to the RF power source.
Energy storage
 Active pulse compressor
Active compressors contain elements with timedependent electrodynamic parameters.
(plasma switch, electron-beam triggered switch)
Energy release
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
SLED-II
Delay line
Input pulse
RF source
3dB hybrid
Resonance Delay Lines
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
Q0 = 1.77x105 , β = 5.98
Peak Power Gain : 6
6
5
Output power
S21/dB
-0.5
-1
-1.5
4
3
2
1
-2
-2.5
-3
Relative size
Input power
0
Output power
Input power
SLED transmission spectrum
-0.02
0
0.02
Frequency/GHz
0
0
＋
500
－
1000
t/ns
1500
The input pulse can be considered as two parts
Methods to obtain flat-top pulse
3
 SLED
Phase modulation
• Amplitude modulation
Relative size
•
2.5
Output power
Input power
2
1.5
Power Gain : 2.8
Efficiency: 47%
1
0.5
 SLED-II
0
0
500
1000
t/ns
1500
Long delay line
The output pulse of SLED-II
2 x 41.5 m,  77 mm
SLEDII transmission spectrum
Port 1
Port 2
3dB hybrid
Power Gain : 4.1
Efficiency: 68%
Multi-stage X-band pulse compressor
QS0 = 1.77x105, βS = 5.98
QC0 = 4x104, βC = 1.4
Power after correction cavities
The spectrum of the system
0
3.5
3
Relative size
S21/dB
-5
-10
-15
T compressed
Output power
Input power
Power after correction cavites
2.5
2
Efficiency: 61%
1.5
1
f1/T compressed
-20
Average Power Gain : 3.68
4
-0.02
0
0.02
Frequency/GHz
0.5
0
0
200
400
600
800
1000
1200
1400
1600
t/ns
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
Resonant cavity
444 mm
Compact mode launcher
3dB hybrid
Correction cavities
θ
Cavity operation mode TE012
a=32.26mm
251.7 mm
φ r
Small coupling Cavity
Dual-mode
circular polarizer
S21/dB
0
-5
-10
-15
74.9 mm
11.3 11.35 11.4 11.45 11.5
Frequency/GHz
Circular polarizer
Port2（Mode 2）
Port3（Mode 3， Mode 4）
Mode 3
Mode 4
0
Port1（Mode 1）
dB
-20
S11
S12
S13
-40
Mode1 and mode2 are isolated
-60
10.5
11
11.5
12
Frequency/GHz
2014-SLAC-Wang Juwen-Advances in RF Deflector and Pulse Compression System
The full design
QC0 = 4x104
βC = 1.4
0
251.7 mm
-10
-15
-20
170 mm
f
-0.02
266 mm
0
0.02
Frequency/GHz
6
QS0 = 1.77x105
βS = 5.98
1
Power gain
5
0.8
4
0.6
3
0.4
2
0.2
1
444 mm
0
3
4
5
6
7
8
Compression ratio
9
0
10
Efficiency
S21/dB
-5
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
Klystron 2
Klystron 1
Hybrid 1
Load 1
Load 2
Hybrid 2
Pin
Compressor 1
Pout
1
PM-AM principle
0.8
150
0.6
100
0.4
50
0.2
0
0
100
200
θ /Degree
Compressor 2
Linac 1—10
CLIC power supply system
based on klystrons
300
0
Phase/Degree
ej(pi/2+θ)
ej(0-θ)
Normalized output Power
PM-AM modulation
PM-AM modulation
4
3
5
Relative size
Relative size
5
Output power
Input power
Power after correction cavites
2
1
4
3
2
1
0
0
500
1000
1500
2000
0
0
2500
t/ns
1000
1500
2000
2500
6
5
Output power:425MW
Power Gain
200
150
100
Input Power:102MW
4
6
8
Compression ratio
10
1
Power Gain: 4.18 0.8
4
0.6
3
2
0.4
Efficiency:0.46
1
0
4
6
8
Compression
Compression ratio
ratio
0.2
0
10
Efficiency
Input Power
500
t/ns
250
50
Output power
Input power
Power after correction cavites
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
5
6
4.5
4.5
5
Output power
Input power
Power after correction cavites
4
4 correction cavities
2 correction cavities
4
Output power
Input power
Power after correction cavites
4
3.5
Output power
Input power
Power after correction cavites
3.5
3
3
2.5
2.5
3
2
2
2
1.5
1.5
1
1
0.5
0.5
1
0
0
0
200
400
600
800
1000
1200
1400
1600
0
400
600
800
1000
1200
1400
1600
3
200
3
2.5
2
2
2
1.5
1.5
1.5
1
1
1
0.5
0.5
0.5
200
400
600
800
1000
1200
1400
1600
0
800
1000
1200
1400
1600
0
200
400
600
800
1000
Output power
Input power
Power after correction cavites
3
2.5
0
600
3.5
Output power
Input power
Power after correction cavites
2.5
0
400
4
3.5
Output power
Input power
Power after correction cavites
0
16 correction cavities
4
3.5
0
8 correction cavities
6 correction cavities
4
200
1200
1400
1600
0
0
200
400
600
800
1000
1200
1400
1600
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