C-band RF System R&D reported by T. Shintake KEK / RIKEN Japan Summary of C-band R&D for Linear Collider at KEK New soft-x-ray FEL Project at RIKEN/SPring-8 Project was funded in 2001 April Material Science Program at RIKEN Multi-laboratory joint project (SPring-8, RIKEN, KEK,,,,).String Test for C-band RF System for Linear Collider Presented at 9th International Workshop on Linear Collider (LC02) at SLAC Stanford University, Feb. 2002
C-band R&D JLC C-band (5712 MHz) Main Linac Tunnel Granite: stable ground RF Pulse compressor 50 MW x 2 Klystron gallery Diameter: 3.0 m Diameter: 4.2 m Active Length: 14 km RF pulse compressor klystrons 50 MW 2.5 µsec 36 MV/m Gain: x 3.5 Conventional wave-guide system BPMs 36 MV/m (45 MV/m) 8m Accelerator 1.8 m each beam
Phase-I R&D Summary C-band R&D C-band Klystron 50MW, OK 2.5 µsec, 47 % Life test >5000 hour, OK. Klystron Modulator 110 MW 100 pps Smart modulator using inverter HV charger. OK Running for klystron life test. RF Pulse Compressor Flat Pulse Gain 3.3 Three-cell cavity. 1 m long cold model. Hot Model Test in 2001 Accelerating Structure 1.8 m Choke-Mode OK Beam acceleration at 50 MV/m was done at ATF-KEK, with S-band model. HOM damping performance was proved by ASSET- SLAC test, 1998.
Machine Parameters C-band R&D Overall Parameter Klystron C.M. Energy 500 GeV Klystron Power 50MW,2.5 µsec Nominal Luminosity ~5x10 33 Modulator 110 MW, 25kV Beam Current 1.6nC x 72 bunch x 100 pps Spot Size at IP 4x300 nm Bunch Length 0.2 mm Bunch Separation 2.8 nsec Main Linac Parameter Main Linac Length 14 km Number of RF Unit 2000 Units Efficiency Compression Gain Efficiency Accelerating Structure Accelerating Gradient Shunt-Impedance RF Pulse Compressor 50% x3.5 70% 36 MV/m (with beam) 45MV/m (no load) 60 MΩ/m AC Power 200 MW Alignment Tolerance 50 µm
C-band Klystron R&D Program C-band R&D JFY???? for C-band 1TeV JLC Plan: 70MW, 70% PPM Klystron 2001 E3747 #2 2000 Target : 50MW, 50% Under development PPM Klystron 1999 E3747 #1 Plan: PPM Klystron Target : 50MW (37 MW), 50% (34%) PPM Klystron 1998 1997 1996 500 GeV Model E3746 #2 E3746 #1 E3746 #3 Achieved: 53MW, 47% Life-test : 1999 March ~ Achieved: 53MW, 44%, 2.5µsec, 50pps Life-test > 5000 hours OK Achieved: 46MW, 42%, 2.5µsec, 25pps Traveling-wave Solenoid Traveling-wave Solenoid Single Gap Solenoid
C-band Klystron Development Under life test since April 1999 C-band R&D TOSHIBA E3746 No.3 53 MW, 2.5 µsec Traveling-wave output structure Solenoid Focus (4.6kW) 1 µs/div 368 kv 53 MW, 2.5 µsec 1.5 µp Dispenser Cathode (D74.5mm,6.3A/cm 2 ) 53 MW, 2.5 µsec, 50 pps, 47% 0.5 µs/div
Traveling-wave Output Structure C-band R&D 3 - cell traveling π / 2 - mode Reduced surface field 45 29 MV/m Stable beam envelop Lowered focusing solenoid power (4.6 kw) Lowered X-ray emission Enhanced efficiency 41 47% Coupled Resonator Model
Klystron Simulation C-band R&D 2D Particle-in-Cell Maxwell Eq. Relativistic
60 50 C-band 50 MW Klystron TOSHIBA E3746 #2 Traveling wave output cavity (π/2, 3 cavities) Measured rf power by absolute calorymetric methode C-band R&D JULY 1998 RF Output Power [MW] Efficiency [%] 40 30 20 10 Efficiency from beam to rf power Simulated rf power by FCI RF pulse width: 2.0 µsec Pepetition rate: 50 pps 0 150 200 250 300 350 400 Beam Voltage [kv]
Operation Statistics C-band R&D Accumulated Run Time [hour] 1500 1000 500 E3746#2: 50 MW C-band Klystron Test Period: 1998.5 ~ 1999.1 2500 Total Run time : 2000 4,000 hours 1.3 x 10 10 shots 0 25~35 35~45 45~55 Output RF Power Level [MW] Number of Faults 16 14 12 10 8 6 4 2 Operation Condition : Water Load RF pulse length : 2.5 µs Repetition rate : 50 Hz Number of Faults MTBF 1020 h GUN ARC MTBF 161 h GUN ARC W.G Vacuum MTBF 74 h GUN ARC W.G Vacuum 0 25~35 35~45 45~55 Output RF Power Level [MW]
C-band R&D C-band PPM Klystron (1999 Model) Permanent Magnet : NdFeB Shinetsu N40A: Br 1.2 T, Hc 10.5 koe, db/dt=-0.1%/c, < 80 C Ni plating to avoid corrosion Designed parameter (FCI-simulation) Peak output : 55 MW Efficiency : 50% µ Perveance : 1.53 Voltage : 350 kv TOSHIBA E3758
PPM Magnet Test C-band R&D NdFeB magnet sandwiched in iron pole pieces. Test Result Bz.peak = 2047 G, 2% lower than simulation: OK (tolerance ~3%) Field center error <20 µm: OK (tolerance ~300 µm) Piece to piece error +- 0.15 %: OK
Final Machined PPM Elements C-band R&D Machining accuracy and surface roughness of all the PPM elements are within ±25-µm and ±0.6-µm respectively. COPPE R (OFC) Mag-SUS COPPE R (OFC) Vacuum capsule
C-band R&D Diffusion Bonding of PPM Stack Copper pipe PPM Stack HOT ISOSTATIC PRESSING 2 Hours Heater Ar GAS 1200 kgf / cm 2 800 Time
C-band R&D Machineability Survey on PPM Stack Diffusion bonded sample Hot Isostatic Pressing (HIP): 800 C, 1200 kgf/cm 2 and 2 hours Tensile strength: 213 ~ 216 N/mm 2 No He-leak at 10-10 Atm cm 3 /s (after heat cycle at 900 C and 10 minute) Cutaway view of PPM stack
PPM Stacks after Final Machining Diffusion bonded PPM stuck used HIP method at 1200 kgf/cm 2 of Ar-gas pressure, 800 deg-c of temperature for 2 hours. C-band R&D Magnetic stainless steel Input cavity Input cavity Tensile strength at bonded zone is 213~216 N/mm 2. End beam pipe All PPM stacks displayed from input cavity (up left) to end beam pipe (down right).
C-band R&D PPM-module Mounting Procedure
C-band R&D The 1 st C-band PPM Klystron is Under Testing Target performances are RF output power: 50 MW Voltage: 350 kv Repetition rate: 50 pps
RF Pulse Compressor C-band R&D Cold-Model Cavity φ 153 TE0,1,15 TE0,1,5 TE0,1,15 1.2 m Mode Converter
Test Result on Cold Model C-band R&D 1997 Compressed Pulse Magnified View G v 3.3 Flat top 230 nsec 0.5 µs/div * 5712 MHz, Low level signal, * AM-modulation by a mixer, * HP function generator 0.1 µs/div
C-band R&D TE 01,15 test cavity for Pulse Compressor Q 0 = 185000(97%), Q ext = 18400 EBW brazing OFC Super invar with copper electroforming OFC MOF Mode converter TE 10 TE 01
C-band Smart Modulator No. 1 C-band R&D Charging voltage of EMI-303 Inverter power supply EMI-303 Peak power output: 111 MW Average power output: 39 kw Charging voltage: 47 kv Flat top pulse width: 2.5 µsec Thyratron switch noise ~5 MHz 23 kv, 4600 A PFN output voltage
C-BAND 50 MW KLYSTRON C-band Closed type Compact Modulator for FEL project W: 1600, D: 1500, H: 1000 Include two set of modules 821 1000 100 (1766) (1966) 1600 700
SPring-8 Compact SASE Source (SCSS) presented by T. Shintake Project Overview Milestone Key Technology Electron Gun High-gradient C-band Accelerator In-vacuum Undulator
Where to build FEL? Experimental Hall S ring-8
What is SASE? Self Amplification of Spontaneous Emission (Noise) No Mirror is available below 100 nm. No seeding source is available. Noise Noise Noise Noise output Coherency is quite limited (~1µm) Monocromatic (~0.1%width)
SPring-8 Compact SASE Source E = 0.5 MeV Ipk = 3 A t = 0.33 nsec q = 1 nc 20 MeV 30 A 33 psec 1 nc z~10 mm 20 MeV 250 A 4 psec 1 nc 1.2 mm E = 300 MeV Ipk = 2 ka t = 0.5 psec.fwhm q = 1 nc z = 0.15 mm.fwhm E = 1 GeV Ipk = 2 ka t = 0.5 psec.fwhm q = 1 nc z = 0.15 mm.fwhm σe/e = 2x10 4 εn = 2 πmm.mrad λ x = 3.6 nm ρ =8.9 x 10 4 Lg = 0.94 m Lsat = 20 m Psat = 1.9 GW 500 kv Pulse Gun 476 MHz Buncher ~200 kv L-band Linac C-band Linac C-band Linac Undulator BC1 Unit-1 BC2 Unit-2 Unit-3 Unit-4 Energy Filter 20 MV 1 m 476 MHz Stepup Cavity ~600 kv x1/8.3 40 MV/m 1.8 m x 4/unit 288 MeV/unit C-band Correction Cavity ~1 MV x1/8 40 MV/m 1.8 m x 4/unit 288 MeV/unit λu = 15 mm Kmax = 1.3 g.min = 3.7 mm <βx,y> = 10 m L = 4.5 x 5 = 22.5 m
HV Pulse Gun Sub-harmonic Buncher Energy Filter 476MHz Step-up Accelerator L-Band Accelerator Bunch Compressor BC1 400 800 2000 EZ : Einzel Lens HS, VS : Steering Screen Monitor Troid Current Monitor Collimator Beam Chopper (pulse shaping) 476 MHz, 200 kv Vertical Slit (beam chopper) Horizontal Slit (energy gate) 476 MHz, 700 kv 1428 MHz 10 Cell, 1 m APS Standing Wave Energy Gain 20 MV S-band Correction Cavity To Main Linac 1:20 Cathode CeB6 single-crystal φ3 mm 1450 deg.c εn 0.4 π µrad Vp 500 kv I p 3 A t FWHM 300 nsec fr 60 pps K 0.01 µa/v 1.5 Filter 400~600 kv I p 3 A t FWHM 0.3 nsec Vp 1 MV I p 10 A t FWHM 100 psec Q 1 nc Vp 20 MV I p 30 A t FWHM 33 psec Q 1 nc Vp 20 MV I p 250 A t FWHM 4 psec Q 1 nc