C-band Accelerator system for XFEL / SPring-8 C. Kondo, T. Inagaki, T. Shintake for XFEL project in...
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Transcript of C-band Accelerator system for XFEL / SPring-8 C. Kondo, T. Inagaki, T. Shintake for XFEL project in...
C-band Accelerator systemfor XFEL / SPring-8
C. Kondo, T. Inagaki, T. Shintake
for XFEL project in SPring-8
6/Oct/2008Seminar at SLAC
[email protected]@spring8.or.jp
8 GeV XFEL Machine Layout
InjectorS-band4 units C-band (42 off-crest) 12 units
C-band (crest) 52 units
Undulators
30 MeV100 A
500 keV1 A x 1 ns
1.4 GeV3 kA
8 GeV3 kA
400 MeV1 kA
Bunch compression
Acceleration
X-ray Lasermin < 0.1 nm
Ea = 35 MV/m
V/V ~ 0.01%rms
~ 0.2 deg.rms
V/V ~ 0.01%rms
~ 0.5 deg.rms
C-band (5712 MHz) RF system
HV Charger HV Charger
Pulse-to-pulse jitter from the klystron voltage
HV Charger
AC 420 V
XFEL requires (rms) - Intensity 0.01% - Phase 0.2 °
Modulator
Charging 50 kV
Klystron
Pulse -350 kV
Pulse Comp.
RF 50 MW
RF 70 MW 2
Accel. Struct.
0.01 %
0.01 %high precision HV charger with <0.01% (100 ppm) stability
Improvement of High Voltage Charger
Specification:・ Switching device IGBT・ Charging voltage Max. 50 kV・ Charging current ~ 2 A・ Average output power 36 kW・ Repetition 60 Hz・ Voltage stability (jitter) 0.01 %rms
Aug. 2006, Nichicon Corp.Used at prototype acc.
Feb. 2008, Nichicon Corp.
Nov. 2007, Toshiba electro-wave,
Block Diagram of HV Charger
Full-wave rectification
AC420 V
Full bridgeswitching
Main
Sub
ResonanceHigh voltagerectification
DC600 V
Max. 50 kV
We use Main charger and Sub charger.“Main” charges 99.5%, fast but roughly“Sub” charges up to the target voltage, slowly but accurately.
Feedback Control of Charged Voltage
HV charger Modulator
PFN Capacitors
HV probeJapan finechem inc. 2007
Feedback of the voltage
Error amp.
Reference voltage
Stray capacitance delays the responseMain resistor : 1 G→100 M・ Time constant: 1 msec→100 sec・ Heat loss: Fluorinert, Cooling water.
New HV charger with 10 ppm (rms) stability
Prototype modelFeb. 2008, Nichicon Corp.
This stability satisfies the requirement at XFEL (<100 ppm).
Typical HV charging cycle(Tens of waveforms are overlaid)
C-band (5712 MHz) RF system
Compact “all-in-one” modulator Compact “all-in-one” modulator
“New” modulatorOne tank including the pulse transformer and modulator
Pulse Transformer
PFN circuitCapacitor x16
(General Atomics)
Thyratrone2v CX-1836
EOL circuitDiode & Resistor
Klystroncathode
Nihon Koshuha Co. Ltd., Oct./2007Compact size: 1.7m x 1m x 1.2m, EM noise shielding, etc.
Thyratron and PFN Circuit (Detail)
Thyratron e2v, CX-1836・ Deuterium filled・ Impregnated cathode・ Double gap, twin trigger
・ Cooled by natural oil flow Omit forced oil flow.
Pulse Forming Network circuit ZPFN = 4 ・ Capacitor : General Atomics, Max. 50 kV 0.029 F ×16 series・ Coil 0.6 H ×16 series
Replace
Other circuit EOL, tail clipper, shunt diode, discharging resistor, etc
Pulse Transformer (detail)
RISHO Co. (Japan)
Turn ratio: 1:16 ( Prim=6 turn 、 Sec=96 turn )Primary voltage: -22 kVSecondary voltage: -350 KV
Epoxy-molded winding ・ High voltage insulation ・ Suppression of wire vibration
Oil cooling system of the modulator
• Concept• Fan-less cooling for viscous insulation oil• Low cost, Compact
• Requirements• Heat generation: ~3kW
• Heater ~1kW ( thyratron cathode, Klystron cathode)• Current loss ~2kW @ 45kV,60pps ( EOL, thy. Anode, Core Loss,
etc)
• Oil temperature : < 45 ℃• We measured the practical heat transfer coefficient
by model tank.• And, we designed the optimum cooling system for the
modulator.
View of Cooling system
2 panel type on partition wall
Cooling panel
1 pipe type on top board
Cooling pipe
2 panel type on side board
Cooling panel (side board)
Oil temperature
Oil temperature on nominal operation
Operation: 45 kV charging 60 ppsCooling water: 26 ℃, 8 L/min
Oil temperature: < 43 ℃
Oil
Te
mp
era
ture
(℃
)
C-band (5712 MHz) RF system
C-band Klystron C-band Klystron
50MW pulse klystron
Output power : 50 MW
Frequency: 5712 MHz
RF pulse width: 2.5 sec
Beam Voltage: -350 kV
Beam Current: 310 A
Repetition: 60 pps
TOSHIBA ELECTRON TUBES & DEVICES CO.LTD.
Model No. E37202
In the test accelerator, no trouble for 3,000 hours
C-band (5712 MHz) RF system
Pulse compressorPulse compressor
C-band accelerator structureC-band accelerator structure
RF pulse compressorFabricated by Mitsubishi
Heavy Industries Ltd.
High-Q cavities mode: TE0,1,15
Q0 : 190,000 : 9.5
Mode converters (Shintake 1996) - Waveguide(TE10) Circular(TE0,1,x) - 4 coupling holes Lower rf field at the coupling hole
Input
50 MW
2.5 s
200 MW peak
0.5 s
Output
Directional coupler
Accelerating structure(Shintake structure)
Choke mode cavity (Shintake 1992) - traps the accel. mode (5712 MHz) - eliminate HOM (not 5712 MHz)
multi-bunch operation
High acceleration gradient R~ 54 M/m, ~ 0.53, L=1.8 m Ea = 35 MV/m with 63 MW x 300 nsec rf power
Fabricated by Mitsubishi Heavy Industries Ltd.
19.7
SiC absorber
Mass production of the accelerating structure@ Mitsubishi Heavy Industries Ltd.
Precise lathe
Shipping
Dr. Miura(Mitsubishi)
Cells
High power rf test bunker (July 2008 ~)
Accel. struct. Waveguide RF pulse compressor Modulator Klystron
In order to check quality of the delivered components, we constructed the test bunker. Now, rf processing is in progress.
Modulator development team
白澤近藤櫻井
稲垣武部
新竹
T. Inagaki
C. Kondo
T. Shintake
S. Indo
K. Nakajima
T. Sakurai K. Shirasawa
Summary
Highly precise charger • Parallel charging system• New HV probe of fast response-time.• Stability of charging voltage ~10 ppm (rms)
New “all-in-one” modulator power supply• Compact oil-filled power supply.• EM noise shielding, fan-less oil-cooling system …• No trouble operation for 700 hours
Schedule• High power rf components were delivered on schedule.• Quality will be checked at the rf test bunker.• 2009~2010 installation• 2011~ Beam commissioning
Thank You!