Magnetrons - High Power RF Sources - INDICO-FNAL (Indico)
Magnetrons - High Power RF SourcesBrian Chase - FermilabMichael Read - Calabazas Creek Research Inc
Magnetron Collaboration Calabazas Creek Research Inc– Michael Read, R. Lawrence Ives, Thuc Bui Fermi National Accelerator Laboratory– Brian Chase, Ralph Pasquinelli, Ed Cullerton, Philip VargheseJosh Einstein, John Reid Communications and Power Industries LLC– Chris Walker, Jeff Conant2Chase Science and Technology WG4/05/18
Outline Demands for high power, high efficiency RF Vector control schemes for magnetrons Experimental results Ongoing research3Chase Science and Technology WG4/05/18
Take-a-ways from the Proton Driver High EfficiencyWorkshop at PSI Proton Drivers:- GeV-energy range- MW-beam power range Applications: neutrinos, muons, neutrons, Accelerator DrivenSystems(ADS). Types of accelerators for proton drivers:- Cyclotrons and Fixed-Field Alternating Gradient accelerators (FFAG);- Rapid Cycle Synchrotrons (RCS);- High intensity pulsed linear accelerators;- CW Superconducting RF linear accelerators. 4High RF efficiency is critical for high beam power applicationChase Science and Technology WG4/05/18
EFFICIENCY - IMPACT Cooler - More reliableGMRR VG10-1A5Chase Science and Technology WG Lower operating cost Lower HVAC requirements4PROPRIETARY INFORMATION4/05/18
The basics of magnetron operationCathode at negative potentialaccelerates electrons outward.B field causes electrons to spiralE field across gaps causes bunching intoelectron cloud spokes. Rotating spokesintern excites cavities. RF power iscoupled out and is constant amplitude.Injection Locking:RF maybe driven in on same port andcause the spokes to phase lock up tosource providing low noise RFAmos DexterCross section of a cookermagnetron showing cathodeand RF cavitiesR. Adler, A study of locking phenomena in oscillators, Proc. IRE andWaves and Electrons, vol. 61, no. 10, pp. 351-357, June 1946.6Chase Science and Technology WG4/05/18
Magnetrons excel at many RF source requirements Power: 100 kW CW and MW scale pulsed operation– average power capability increase with lower frequency Efficiency: High power devices 85% at L-band Power supply voltage: typically 25kV Low cost: 0.50/watt at 100kW and 50 units Small size: 100 kW pulsed 1300 MHz tube is 1 foot high anddoes not require an oil tank They are easy to replace and rebuild and can be designed fora reasonably long life and low noise when injection locked However, they are basically a constant power device, not alinear amplifier like a klystron7Chase Science and Technology WG4/05/18
Industrial CW Magnetrons8 High power CW magnetrons used forindustrial heating are catalog items 85% efficiency typical 100 kW L-band - 18” length, 5” diameterChase Science and Technology WG4/05/18
Phase control loop around SRF cavityLancaster: Amos Dexter, Graeme Burt and Chris LingwoodDemonstration of CW 2.45 GHz magnetron driving aspecially manufactured superconducting cavity in a VTFat Jlab.Control of phase in the presence of microphonics wassuccessful.H. Wang et al., “USE OF AN INJECTION LOCKED MAGNETRON TO DRIVE A SUPERCONDUCTING RF CAVITY,” in Proceedings ofIPAC’10, Kyoto, Japan, THPEB067.9Chase Science and Technology WG4/05/18
Cascaded magnetrons and out-phasing AM controlConcept: cascade injection lockedmagnetrons to increase gain, combine twopairs to get amplitude control byoutphasing in pulsed mode operationOutcome: Proof of concept for cascadestage and the realization that we neededCW power supplies to make real progress.Strong belief that this scheme would workbut it does have its complexities.Grigory Kazakevich, et al. Muons Inc.Yakovlev, Pasquinelli, Chase, et al. Fermilab10Chase Science and Technology WG4/05/18
Amplitude control by fast phase modulation techniqueMagnetrons are constant output power devices. However, the power in thecarrier destined for the cavity can be reduced by fast phase modulation,moving power from the carrier into discreet Bessel sidebands that are outsidethe cavity bandwidth. These sidebands will be reflected from the cavity andback to the circulator loadIncreasing the modulationdepth(137 degrees) suppressesthe carrier over a measured 64dB dynamic range in lab11Chase Science and Technology WG4/05/18
Rejection of PM sidebands by Narrowband CavityWhile output power is constant, sinusoidal phase modulationcreates discrete sidebands at multiples of the modulationfrequency while the power shifted from carrier to sidebands isdetermined by modulation depthCavity responseFundamentalPM sidebandsAf12Chase Science and Technology WG4/05/18
Phase Modulation EquationsUsed for generation of amplitude-to-phase LUT. Generates a lookup table such that the regionBefore the first null in the Bessel is covered by the controller. Allows for linearization correctionsby just adding a scaling table.13Chase Science and Technology WG4/05/18
Bessel of the first kind, Region before first nullInverse function in look up table drives phase modulationdepth to linearize cavity drive14Chase Science and Technology WG4/05/18
LLRF controller for 2.45 GHz SRF cavity driven by 1.2 kWMagnetron using Fast Phase Modulation15Chase Science and Technology WG4/05/18
Controller architecture16Chase Science and Technology WG4/05/18
Injection Locked 2.45 GHz magnetron driving SRF cavityInjection Locked 2.45 GHz gnetron'Loaned'SRF'cavity'from'JLab'Tes ublished'in'JINST'Na onal'and'Interna onal'patents'pending'1711!Chase Science and Technology WGRalph J. Pasquinelli P2MAC 2015!4/05/183/9/2015!
A0 VTS 2.4 GHz Magnetron - Cavity test results- Amplitude control shownlinear over 30 dB range- Moderate feedbackperformance demonstrated- 0.3% r.m.s, and phase stabilityof 0.26 degrees r.m.s.- Tests limited by extreme cavitymicrophonics and very limitedtime with the test cave18Chase Science and Technology WGCavity at 4 K, LLRF drive. Blue loops open,Red loops closed and maximum output, Greenloops closed and amplitude reduced by 17 dBshows the PM modulation is effective foramplitude control.4/05/18
Phase Modulation Tests on 1300 MHz 9-cell Cavity 9 cell cavity is driven bya phase modulatedsource through a 4kWsolid state amplifier8/9 pi mode driven by carefully tuned 2nd sidebandForward power from SSA19Chase Science and Technology WG8/9 pi mode is easily not excited by sidebands4/05/18
CCR / CPI - 100 kW Pulsed, 10 kW Ave. 1.3 GHz MagnetronCalabazas Creek Research IncPhase II SBIR grant to develop a 1.3 GHz, 100 kWpeak power, 10 kW average power magnetronstation in partnership with Fermilab andCommunications and Power Industries LLC, utilizinga full vector control scheme developed by Fermilab.254A Magnet Current20kV4.5A Magnet Current155A Magnet Current105.5A Magnet Current500246AmpsV-I Characteristics of Magnetron atVarying Electromagnet CurrentValues from initial short pulse tests.20Chase Science and Technology WG86A Magnet Currenttube 12” tall4/05/18
CCR 1.3 GHz 100 kW magnetron testing at HTS FermilabIsolator with shorting plateDiagnosticsand controlWater cooledloadHigh voltagemodulatornot shownKlystron100 kW Magnetron21Chase Science and Technology WG4/05/18
1.3 GHz 100 kW magnetron test results 100 kW injection locked power with 5 msec. pulses Good phase modulation bandwidth Expect no problem with 10kw average power22Chase Science and Technology WG4/05/18
LLRF Digital Control Card for Phase Modulation Scheme(16) 14 bit ADCs (8)14 bit DACs System on ModuleDual core Armprocessorwith FPGA eliminatesthe need for a crateand externalprocessor.23Chase Science and Technology WG4/05/18
Magnetron Control R&D moving forward Cathode voltage and solenoid current control is a logicalchoice for slow amplitude control to optimize efficiency foroperating conditions– there is potential for moderate bandwidth with switch-mode PS– should be a part of any scheme RF vector control through fast phase modulation is a potentialfit for many machine designs– single tube design with greatest hardware simplicity– at the cost of control complexity Working towards a 650 MHz 150 kW magnetron for industrialaccelerators24Chase Science and Technology WG4/05/18
Summary The magnetron has been a remarkable RF source for 75 years thatis unparalleled in cost and highly efficient. It is widely used forindustrial heating and smaller electron accelerators but has hadlittle impact in hadron accelerators There are now several control architectures that can takeadvantage of the processing capabilities of modern FPGAs Initial testing with a 1.3 GHz 100 kW 10% duty factor magnetronand controller using fast phase modulation is complete. Magnetrons may be a strong contender for high power, highefficiency accelerators25Chase Science and Technology WG4/05/18
Thank you for your attention!26Chase Science and Technology WG4/05/18
Backup slides27Chase Science and Technology WG4/05/18
References B. Chase, R. Pasquinelli, E. Cullerton, and P. Varghese,“Precision Vector Control of a Superconducting RF Cavitydriven by an Injection Locked Magnetron,” Journal ofInstrumentation, no. 10 P03007, 2015. H. Wang et al., “USE OF AN INJECTION LOCKEDMAGNETRON TO DRIVE A SUPERCONDUCTING RFCAVITY,” in Proceedings of IPAC’10, Kyoto, Japan,THPEB067.28Chase Science and Technology WG4/05/18
Efficiency Goals 29For high power SRF linacs the RF sources are a keycomponent in overall wall-plug efficiencyChase Science and Technology WG4/05/18
Amos Dexter30Chase Science and Technology WG4/05/18
A0 Vertical test stand, Jlab 2.45 GHz single cell undressedcavity RF block diagram Fig1.jpg31Chase Science and Technology WG4/05/18
1950s transmitter using 2 magnetrons and out-phasingPatent awarded in 1952 for a transmitterdesign using cathode voltage modulationand out-phasing with two magnetronsWhy was this technology discarded?- Possibly just too many parts andexpense.32Chase Science and Technology WG4/05/18
Apr 05, 2018 · Demonstration of CW 2.45 GHz magnetron driving a . CCR 1.3 GHz 100 kW magnetron testing at HTS Fermilab Chase Science and Technology WG 4/05/18 Isolator with shorting plate Klystron . A0 Vertical test stand, Jlab 2.45 GHz
the College of Electronics and Information Engineering, Sichuan University, Chengdu 610017, China, and also with the Key Laboratory of Wireless Power . power microwave sources with two- and four-way waveguide power combining systems, which utilized phase shifters to . Penn State Univer
Richardson Electronics can perform electrical tests on RF assemblies and components, microwave assemblies, electron/vacuum tubes, industrial power tubes, and CW magnetrons. Richardson Electronics can also perform high-power/high-voltage testing on RF assemblies, vacuum tubes, capacitors, i
Microwave Mouhcine Lahame1, Mohammed 3, Chraygane2, Hamid Outzguinrimt Rajaa Oumghar4 . Abstract—This article deals with the optimization of a three-phase tetrahedral-type high voltage transformer, sized to supply three voltage-doubling cells and three magnetrons per phase. The optimization method used is based on an algorithm implemented
frequency and phase locking of oscillators and magnetrons a thesis submitted to the graduate school of natural
The magnetrons were slightly unbalanced for the Ti and Zr target, and balanced for the Ta one. One can see that large compressive stress initially develops, the instantaneous stress reaching 5 GPa for h 20 nm. With increasing film thickness, different stress evolutions are evi
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sages and ascetics have elaborated and refined the abstract concepts of life explained in the Vedas. Sources of Hindu Law Sources of Hindu Law can be divided into two parts - Ancient and Modern. 1. Ancient Sources Before the codification of Hindu Law, the ancient literature was the only source of the law. These sources can be divided into four .
The API Specification and the EEMUA Specification differ slightly in some respects. The main differences in the specifications are in the requirements for the rheological properties and filtrate loss of the slurry. The rheological properties of the slurry at different rates of shear are determined using a direct reading viscometer. Filtrate loss is determined using a filter press. Test methods .
