RF POWER SOURCE SYSTEMS FOR TAC IR FEL FACILITY

Transcription

1 RF POWER SOURCE SYSTEMS FOR TAC IR FEL FACILITY Özlem KARSLI Avni AKSOY Prof.Dr.Ömer YAVAŞ , Bodrum

2 OUTLINE Overview of RF system of TAC IR FEL Facility. RF sources (Klystron, IOT & Solid State Amplifiers). RF Transmission Lines. RF Waveguide Distribution System. Summary

3 Layout of TAC IR-FEL Facility

4 Basic RF System Layout

5 Each RF station will include; a power amplifier, several auxiliary power supplies for amplifiers, the pulse transformer, a low-level RF system, an interlock and control system, a modulator (power source), cables, a waveguide distribution system and linac.

6 A Typical RF Station elementaries Amp. Loop Phase Loop (or I/Q Loop) Cavity Tuning Loop Cavity Protection Auxiliaries Circulator Waveguide Master Source LLRF Pre-Ampl. Power Ampl. Power Supply Modulator Load Acc. cavity

7 RF Sources Klystron IOT Solid Stade Amplifier

8 Inductive Output Tube (IOT) Klystron The IOT is an RF power amplifier combining features of the Klystron. Like the klystron it uses a magnetically-focused cylindrical electron beam, accelerated by negative beam voltage between cathode and body, a drift region, an annular output cavity, and a spent-beam collector. The cathode current is directly density modulated in response to the RF voltage between grid and cathode, in the form of sequential discs, rather than a continuous, velocity-modulated beam as in a klystron.

9 Comparison of Klystron and IOT for 16KW CW and pulsed mode at 1300 MHz Klystron IOT Efficiency 50-60% 65-75% Gain 40-50dB 20-23dB Availability Develop. required* Available** Modulation Requires beam current modulation Modulated by RF input *10kW 1300 MHz Klystron exists, but with 37% efficiency **Pulsed Mode is unstable.

10 Solid State Amplifiers Extreme modularity High redundancy: no interruption if some modules fail No need for HV No high power circulator Simple start up procedures Easyoperation

11 Solid State Amplifiers Parallel combining; 100 s of 300 to 1000 W RF modules to obtain 100 s of kw total RF power.

12 Solid State Amplifiers Frequency Power Efficiency Class AB > Class A Gain Class A > Class AB RF Rise/Fall Time few MHz- several GHz To ~kw %55-70 %55-60 ~ns Front view of CRE GHz 1kW SS Ampl.

13 RF Transmission Lines Coaxial Transmission Lines (to the buncher cavities) Waveguides (to TESLA cavities ).

14 RF Waveguide Distribution System circulator to the cavity rf amp. directional coupler tuner load

15 RF Waveguide Distribution System Waveguide Designation Inside Dimension (inches) H 10 mode Operating Range (MHz) Cutoff Frequency (MHz) Cutoff Wavelength (cm) WR x WR x WR x WR x WR x WR x WR x WR x

16 Summary Solid state amplifiers entered field of high power RF generation: Highly innovative approach next trend for accelerator applications Could open the door to highly industrialised mass production of RF power modules Extremely modular: probably easy to operate and maintain even for small crews RF power and waveguide distribution system optimization for TARLA will be detailed by the mid of next year. Most of the components of the RF stations will be installed in the ground floor of the TARLA Facility. On the other hand, the final decision will be given at the end of the whole RF system optimization.

17 Thanks a lot for your attention!!!

18 REFERENCES Campisi I.E., Farkas Z. D. Superconductors for pulsed RF accelerators, SLAC-PUB 3617, April Ayvazyan Valeri, Simrock Stefan N., Dynamic Lorentz Force Detuning Studies in TESLA cavities, Proceedings of EPAC 2004, Lucerne, Switzerland V.Katalev, S.Choroba, Tuning of External Q and Phase for The Cavities of a Superconducting Linear Accelerator, Proceedings of LINAC 2004, Lübeck, Germany B.Avenue et al. The Superconducting TESLA Cavities, Physical Review Special Topics, Accelerators and Beams, Volume 3, , 2000 Zavadtsev A. et al. Solid State High Power RF System For Super Conducting Cavities, Proceeding of PAC09,Vancouver, BC, Canada. Cooper R.K., High Power Rf Transmission Editor Turner S., CAS RF Engineering for Particle Accelerators, p , Volume 1, Mitra A. K. et. al., Solid State Amplifiers for Linear Accelerators at TRIUMF, 14th International Conference on RF Superconductivity, Berlin, September 20-25