Side Coupled Linac Design at CERN M. Pasini, Abingdon September 28 th , 2005
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Transcript of Side Coupled Linac Design at CERN M. Pasini, Abingdon September 28 th , 2005
MP - HIPPI General meeting, Abingdon October 28-30, 2005
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Side Coupled Linac Design Side Coupled Linac Design at CERNat CERN
M. Pasini, Abingdon September 28th, 2005
MP - HIPPI General meeting, Abingdon October 28-30, 2005
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CONTENTS:CONTENTS:
1. SCL structure
2. Beam Parameters
3. SCL Layout
4. RF studies
5. Frequency error study
6. Conclusions
MP - HIPPI General meeting, Abingdon October 28-30, 2005
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SCL PrinciplesSCL Principles
MP - HIPPI General meeting, Abingdon October 28-30, 2005
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Why SCL?Why SCL?
1. Above 90 MeV the effective Shunt Impedance of the SCL is bigger then the one of the CCDTL.
2. Compared to on-axis coupled structure (OCS) and/or annular-ring-coupled structure (ACS) the SCL offers a good mode separation in the coupling cell and simple and well established tuning procedure.
3. SCL cells can be easily machined on a lathe (using a circular frame) with tolerance within 0.05 mm in the nose cone region.
4. Alternative production technologies like Electrical Discharge Machining (EDM) (investigated by INFN-Naples) might reduce production costs.
MP - HIPPI General meeting, Abingdon October 28-30, 2005
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ZTZT22 Curve Curve
0
10
20
30
40
50
60
0 20 40 60 80 100 120 140 160
Energy (MeV)
ZT
2 (M
Oh
m/m
)
DTL tank1
DTL tank2
DTL tank3
CCDTLSCL
MP - HIPPI General meeting, Abingdon October 28-30, 2005
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Beam Parameters
Particle H-
Initial energy 90 MeV
Final energy 160 MeV
Beam Intensity 40 mA (peak)
Duty Cycle (LINAC 4)
0.08 %
Max Duty Cycle 14 %
Frequency 704.4 MHz
Focusing Channel
F0D0
n. acc. cells/tank
11 #
MP - HIPPI General meeting, Abingdon October 28-30, 2005
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SCL Layout design SCL Layout design programprogram
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SCL Layout design SCL Layout design programprogram
MP - HIPPI General meeting, Abingdon October 28-30, 2005
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SCL LayoutSCL Layout
Klystron[#]
Tanks/Kly.[#]
Gradient E0
[MV/m]Power/Kly.
[MW]Energy[MeV]
N cells/tank[#]
1 5 4 3.00 107.42 11
1 5 4 3.06 125.16 11
1 5 4 3.15 144.16 11
1 4 (5)
4 2.59 (3.24)
160.2 (164.31)
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Tot. Klystr.[#]
Tot. tanks[#]
Average Grad.[MV/m]
Tot. Power[MW]
Tot. Length.[m]
4 20 4 12.46 28.02
MP - HIPPI General meeting, Abingdon October 28-30, 2005
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RF Studies with MWSRF Studies with MWS
Coupling and Shunt impedance study as a function of the intersection length
Geometric shapes of the coupling slot and hence coupling factors are well defined because each slot is re-machined
0%
1%
2%
3%
4%
5%
6%
0 10 20 30
d (mm)
K (%)
MP - HIPPI General meeting, Abingdon October 28-30, 2005
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PSPICE SimulationPSPICE Simulation
±50 kHz error only on the accelerating cells
±50 kHz error on the accelerating and coupling cells
0.00%
0.05%
0.10%
0.15%
0.20%
0.25%
0.30%
0.35%
0% 2% 4% 6% 8%
k (%)
Error (%)
STDEV
AVG
0.00%
0.10%
0.20%
0.30%
0.40%
0.50%
0.60%
0% 2% 4% 6% 8%
k (%)
Error (%)
STDEV
AVG
For a complete module of 5 tanks we expect a maximum error of ± 0.9%
for the field level
MP - HIPPI General meeting, Abingdon October 28-30, 2005
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704 MHz Klystrons704 MHz Klystrons
Contacts with 2 manufacturers :
Thales – 4 MW single beam klystron
Toshiba – 5 MW multiple beam klystron
Max pulse length = 2ms
Rep rate = 50 Hz
RF duty factor = 10 %
MP - HIPPI General meeting, Abingdon October 28-30, 2005
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Summary / ConclusionsSummary / Conclusions
1. A layout of the SCL section is completed.
2. The new Excel tool allows to design SCL with a variety of free parameters.
3. Coupling coefficients of 3% guarantees low field error (with 50 kHz tuning accuracy) with minimum reduction in Q-value.
4. Design for 2 klystrons meeting our specs are existing.