Solid State Modulators for X-Band Accelerators

Transcription

1 Solid State Modulators for X-Band Accelerators John Kinross-Wright Diversified Technologies, Inc. Bedford, Massachusetts

2 DTI X-Band Experience Developed and built two completely different NLC-class modulator systems for DOE Production ready design DTI has built a number of state-of-the-art, large X-band transmitters for precision radar systems Some transmitter packages include everything from the wall plug to the antenna or linac DTI team is fluent with klystron, TWT, magnetron and gyro- devices as well as IOT and tetrodes Recent pulsed transmitter projects from 150 MHz to 94 GHz Several unique new transmitter systems developed yearly Production to suit customer needs Broad technology base to support almost ANY high power transmitter requirement

3 NLC Dual klystron system Nominal Specifications 500 kv 500 amps 3 Microseconds 120 Hz Dual X-band system shown with single S-band klystron (5045) installed for testing

4 Requirements for Short Pulse Klystron Modulators Technical Requirements High Voltage ( kv) Medium Current ( A per klystron) Fast Risetimes (< 1 us) Short Pulse (1 20 us) Flattop / Stability ( < 0.1 / 0.01 %) Repetition rate ( Hz) One or two klystrons Operational Requirements Extreme Reliability Power efficiency Flexibility / Stability Ease of Maintenance Maximize Klystron Life

5 Short Pulse Klystron Modulator Architectures DTI 500 kv-class modulators include Hybrid, transformer coupled designs as well as solidstate Marx bank systems Hybrid designs take advantage of DTI s unique capability in high voltage solid state switching as well as our advanced high voltage power supply designs Marx bank systems promise the ultimate combination of high efficiency, compact size, and pulse fidelity Hybrid ~ high voltage solid-state hard switch driving a pulse transformer

6 DTI Solid-State Modulators Can Meet the Challenges Series of IGBTs (or FETs), configured for high blocking voltage, high conduction currents, very low losses, fast switching Can be closed, opened arbitrarily Fast high voltage, high current switch is ideal for short or long pulse systems > 150 kilovolts DC > 10 ka peak Power Supply Fast Opening Switch Load < 3 V/kV drop < 1 ma leakage

7 Switch Module and Assembly DTI switch built from high voltage, high current IGBTs 5 kv, 5 ka pulse (10 ka fault) Series stack has large built in redundancy 80 KV switch assembly configured as transmission line DTI builds various switch module types

8 Hybrid Modulator - Overview Modulator I 5µF 80kV High voltage modulator switch * Energy storage capacitor Pulse transformer * High voltage power supply * Controls and housekeeping circuitry * DTI has unique technologies in these areas which combine effectively

9 Hybrid Modulator at SLAC Designed to pulse a pair of X-band klystrons Tested at SLAC w/ 5045 klystron Pulse flat top +/- 0.5%. Rise/fall/flat-top can be optimized to meet pulse fidelity and efficiency requirements

10 Arc Protection 420 kv arc of 5045 klystron protected by switch opening in ~ 1!sec. (blue) Cathode voltage collapses at arc. (red) Cathode current spikes at arc, starts to climb. (brown) Primary current switch opens at < 4000 A.

11 Recent hybrid modulators at DTI S, X, K, Ka band Klystrons and magnetrons 150 nanoseconds 10 microseconds PRF to ~ 5 KHz Laboratory use or portable Commercial or mil Air or oil insulated Linacs and radars Excellent pulse fidelity/stability and reliability in all cases

12 Klystron short pulse transmitter Typical Specifications Cathode voltage < 500 kilovolts Pulse width < 10 s microsec Average power < 250 kilowatts Rep rate < 500 Hz One or two klystrons

13 Transmitter Systems Integration DTI is prepared to deliver complete RF transmitter systems, including Pulsed modulator High voltage power supplies Controls RF High power microwave tube Waveguide Driver Fast protection/llrf Cooling Manifolds Chiller

14 DTI Customer support Installation Training Spares Documentation Follow up support Upgrades

15 Marx Bank Solid-State Modulator Systems DTI has designed and built solid-state Marx banks for both ILC and NLC projects! DOE SBIR funding Both designs based on a fully modular design concept Short pulse (500 kv-microseconds) for X- band klystrons Long pulse (150 kv-milliseconds) for L- band Multiple beam klystron

16 Marx Switch Configuration Charging (parallel) Pulsing (series) Charging circuit (left) switches are off, capacitors charge quickly through common mode chokes. Pulsing Circuit (right) Switches are on, high voltage (nv 0 ) is pulsed on load. Pulse current does not flow through chokes. Intermediate gate drive & diagnostic power provided by additional choke windings.

17 Compact Marx Modulator (original concept) Spiral assembly lowers parasitic capacitance 500 kv, 250 A design desktop size

18 Short pulse Marx modules assembled into racks 3x3 or 4x4 racks hold prewired assemblies one face (below) has daisychain choke interconnects and fiber optic links other face (right) has daisychain pulse interconnects

19 Short Pulse Marx Full Spec Pulse Shows < 200 ns risetime 9-stage short pulse modulator test: 12.5 kv charge 110 kv into 1125 ", 1.8!sec Risetime < 200 ns (10-90%) Short pulse Marx in a funding hiatus, hope to complete for DOE if funds made available red: current (A) blue: voltage (kv)

20 Long Pulse (ILC) Marx System Assembly High voltage systems tested at DTI ~150 KV, 1.5 milliseconds for MBK System drops into 54 x 88 x 54 oil tank Size/volume ~ half of DTI solid-state hard-switched system Expect to complete controls and deliver to DOE

21 Summary Solid State Modulators Have Been Proven Over 300 Fielded Systems from DTI Alone Very High Reliability in Operation Demonstrated Extension of Tube Life Numerous systems delivered for High Voltage, Short Pulse Applications Linacs Radar Benefits Improved Performance Lower Operating Costs Impact - Lower Life Cycle Costs

22 Thanks! Work Supported Under DOE Grants DE-FG02-03ER83638 & DE-FG02-05ER84352 More Information: Diversified Technologies, Inc. 35 Wiggins Ave Bedford MA