June 16, 2015 CLIC WORKSHOP JANUARY 18 – 22, 2016 OPTIMIZED RF UNIT I 1 January 21, 2016 By: Mikael Lindholm

June 16, 2015 WHAT IS AN RF UNIT? I 2 Modulator Klystron Solenoid Magnet Solenoid PS RF Amplifier Filament PS RF Source Ion Pump PS

June 16, 2015 RF UNIT SYSTEM ILLUSTRATION I 3 External Water Cooling System Filament DCPS Core Bias DCPS HVPS #1 - N Control System Unit P o w er Di st ri b uti o n U nit L1 L2 L3 GND Water Cooling Distribution SW #3 SW #1 SW #2 SW #n RF- Source RF- Amplifier Solenoid PS #1-3 Ion Pump PS Modulator X L/min Collector X L/min Body X L/min Solenoid X L/min Trig I pulse U pulse Remote Interface X W, X GHz VAC 50/60Hz Safety Interface 3-phase 480VAC 1-phase 120VAC Solid State Modulator Pulse Transforme r Oil Tank RF XGHz X A CT CVD Water Flow Interlocks Vacuum Interlock Current Interlock Waveguide pressure Int., Arc Int, VSWR Int. L1 N GND VAC 50/60Hz

June 16, 2015 HOW TO OPTIMIZE AN RF UNIT? RF QUALITY  Frequency stability  Phase stability  Power Stability  Time jitter  Efficiency COMPACTNESS LOW COST

June 16, 2015 PULSE SHAPE The ideal Klystron Voltage Pulse The ideal RF Pulse The traditional Klystron Voltage Pulse The traditional RF Pulse

June 16, 2015 OPTIMAL LOAD IMPEDANCE I 6 LOW < 50Ω Optimal 500 – Ω High >10.000Ω Klystron Impedance Rise time Pulse droop

June 16, 2015 EXAMPLE: K2-4 SYSTEM 80MW S-BAND (2012) I kV/µs407 kV/µs Stability: 30 PPM 400kV / 500 A / 4.5us / 60 Hz Impedance 800 Ω Ideal Pulse Useful Power Area Non useful Power Area Non useful Power Area 82% Size: 3m x 1.8m x 1.9m 15 MW/m 2 Δ V/V<0.003% Jitter 5ns

June 16, 2015 PHASE SHIFT DEPENDANCE OF AMPLITUDE STABILITY V=285 kV, L=0,65 m V=362 kV, L=0,5 m S-band 38MW 2998,5 MHz C-band 50MW 5712 MHz V=420 kV, L=0,6 m X-band 50MW MHz

Stable operation in saturated mode 20MW - linear  20MW – in-between  20MW - saturation input: 17W, HVPS: 890Vinput: 43W, HVPS: 770V input: 135W, HVPS: 713V σ phase = 0.025°σ phase = °σ phase = 0.021° σ amplt (rel.) = 0.029% σ amplt (rel.) = 0.018% σ amplt (rel.) = 0.007% 30 min. 27 min. 22 min. Courtesy of R. Kalt and T. Schilcher 2011 rel. pulse-to-pulse amplt. stability pulse-to-pulse phase stability [deg] σ phase, σ amplt : std. deviation over last 40 pulses remark: overall stability < 4·10 -5 (rms) Linear Mode <290 PPM Not staturated <180 PPM Saturation <70 PPM

June 16, 2015 DESIGN FOR SMALL SIZE I 10 Three principal concepts Split Core™ Parallel Switching™ Pulse to Pulse Control™ The inventors of the LCW modulator Mikael Lindholm, SE Walter Crewson, USA David K Woodburn, UK 0 – 1400 VDC 0 – 1400V0 – V

June 16, 2015 EXAMPLE: K1-SYSTEM FOR 7.5 MW S-BAND (2005) I 11 Stability: 1000 PPM (0,1%) 169kV / 105 A / 5us / 10 Hz Size: 1.5m x 0.6m x 1.1m 8 MW/m kV/µs 230 kV/µs

June 16, 2015 DESIGN FOR COMPACTNESS I 12

June 16, : K2-1 SYSTEM FOR 22MW S-BAND 260 kV/µs 238 kV/µs 200kV / 180 A / 4 us / 3 Hz Size: 1.8m x 1.5m x 1.2m 8 MW/m 2 Stability: 100 PPM (0,01%)

June 16, 2015 EXAMPLE: K2-2 SYSTEM 37MW S-BAND (2011) I 14 Storage Ring 3 GeV 18x RF Units S-band 256 kV/µs 248 kV/µs 285kV / 290 A / 4us / 100 Hz Stability: 46 PPM (0,0046%) Size: 1.7m x 1.5m x 1.9m 14 MW/m 2

June 16, 2015 EXAMPLE: K2-1 SYSTEM 6 MW X-BAND (2014) I kV / 99 A / 5us / 400 Hz Stability: 23 PPM (0,0023%) XBOX 3 Size: 1.4m x 1.3m x 1.9m 3.3 MW/m kV/µs 190 kV/µs

June 16, 2015 EXAMPE: K2-3 SYSTEM 60MW S-BAND (2015) I 16 Storage Ring 3 GeV 370kV / 412 A / 2.5us / 100 Hz 2x 10 PW LASER at W/cm Stability: 15 PPM (0,0015%) Size: 2.4m x 1.7m x 1.9m 15 MW/m kV/µs420kV/µs

June 16, 2015 SUMMARY & CONCLUSIONS Main performance range RF Peak Power:0 – 100 MW RF Average Power0 – 100 kW RF Efficiency:35 – 75% Klystron Voltage: 0 – 500 kV (operation in air <60 kV) Klystron current: 0 – 1000 A Impedance: 500 – 2000 Ω RF pulse width: 1 – 200 µs Pulse Repetition Rates: 1 – 2000 Hz Pulse Flatness:0.1 – 2 % Pulse to Pulse stability: 10 – 100 ppm (phase stability deg) Modulator jitter:4 – 10 ns RF Power density:8 – 20 MW/m 2 I 17

June 16, 2015 SUMMARY & CONCLUSIONS Example: Optimised Design RF Unit RF Peak Power:8.5MW RF Average Power14kW RF efficiency:75% Klystron Voltage: 0 – 54kV Klystron current: 0 – 209 A Impedance: 258 Ω RF pulse width: 1 - 5µs Pulse Repetition Rates: 1 – 1000Hz Pulse Flatness:0.5% Pulse to Pulse stability: 70 ppm Mod. Pulse jitter:5ns I 18 Size: 1.1m x 0.6m x 0.6m 13 MW/m 2

June 16, 2015 THANK YOU! I 19