rf technology
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RF Technology. Professor Richard Carter Lancaster University Engineering Department 23 rd November 2006. Research group focus. Electromagnetics High power RF and microwave engineering Particle dynamics in RF electromagnetic fields Vacuum electronics. Courtesy of Thales Electron Devices. - PowerPoint PPT PresentationTRANSCRIPT
RF Technology
Professor Richard CarterLancaster University Engineering Department
23rd November 2006
RF Presentation to CI SAC 23 Nov 2006 2
Research group focus
• Electromagnetics• High power RF and
microwave engineering• Particle dynamics in RF
electromagnetic fields• Vacuum electronics
Courtesy of Thales Electron Devices
RF Presentation to CI SAC 23 Nov 2006 4
Staff
• Academic staff– Prof. Richard Carter– Dr Amos Dexter– Dr Rebecca Seviour
• Research staff– Dr Graeme Burt– Dr Richard Jenkins– Jonny Smith– Imran Tahir– 2 Vacancies
• Research Students– Chris Hill– Sharon Crane– Fay Hannon– Emma Wooldridge– Chris Lingwood
RF Presentation to CI SAC 23 Nov 2006 5
Resources• Microwave laboratory
– Test equipment– High power sources– Vacuum equipment– Auger spectrometer
• Software– Commercial
• (MAFIA, MWS, Lorenz HF, MAGIC, KOBRA3, Accelrys, GdfidL, FEMLab)
– Indigenous • (Small and large-signal models for klystrons and travelling-wave
tubes, models of helix and coupled-cavity slow-wave structures)
RF Presentation to CI SAC 23 Nov 2006 6
Current research projects
• Microwave tubes– Stabilisation of c.w. magnetron oscillators– High power magnetron for IFMIF – Radial inductive output tubes– Multiple beam klystron for CLIC
• Particle accelerators– Energy recovery linac stability for 4GLS– Crab cavity system for the ILC– Collimator for the ILC– High brightness gun for 4GLS
• RF vacuum breakdown (Multipactor)
RF Presentation to CI SAC 23 Nov 2006 7
Future research projects
• Superconducting RF systems
• Parallel operation of stabilised magnetrons
• Secondary electron emission theory
• Cavity technology for the Neutrino Factory
RF Presentation to CI SAC 23 Nov 2006 8
Stabilisation of c.w. magnetron oscillators
• Dr Amos Dexter, Imran Tahir
• PLL control of frequency• Injection locking• Phase locking to better
than 1%• Injected power – 37dB• Magnetrons could be used
as high efficiency, low cost sources for accelerators
-80
-60
-40
-20
0
2.430 2.440 2.450 2.460 2.470
Frequency (GHz)
-80
-60
-40
-20
0
2.43 2.44 2.45 2.46 2.47
Frequency (GHz)
-80
-60
-40
-20
0
2.4496 2.4498 2.45 2.4502 2.4504
Frequency(GHz)
RBW 2KHz
• Free-running magnetron
• Magnetron with PLL frequency control
• Magnetron with PLL control and injection
RF Presentation to CI SAC 23 Nov 2006 9
High Power RF Sources for IFMIF• Prof Richard Carter, Carl Beard• Conceptual design report:1 MW c.w., 175 MHz, 90% efficiency
Diacrode IOT Magnetron
Anode voltage
14 kV 95 kV 60 kV
Anode current
103 A 58 A 20 A
Efficiency 71% 65% (>75% with a multi-element depressed collector
90 %
Gain 13 dB 23 dB > 30 dB
Drive power 50 kW 5 kW < 1 kW
Cooling Anode Collector Anode and (probably) cathode
Electro-magnet
No Yes (except the radial IOT) Yes
Availability Yes Would require 2 - 3 years R&D Would require 4 – 5 years R&D
R&D issues None • Mechanical stability of control grid• Multi-element depressed collector design• Multi-beam and radial beam designs
• Cathode choice for long life• Development of switched mode power supply • Demonstration of simultaneous control of amplitude and phase• Stability
RF Presentation to CI SAC 23 Nov 2006 10
Radial inductive output tubes
• Sharon Crane (PhD student),
• Prof. Richard Carter
• Collaboration with E2V Technologies
• Target 1 GHz, 1 MW c.w.
Collector
Output cavity
Input cavityRF Output
Grid bias and RF Input
Cathode
Anode
RF Presentation to CI SAC 23 Nov 2006 11
Multiple beam klystron for CLIC
• Chris Lingwood (PhD student), Prof. Richard Carter
• Investigation of novel multiple beam klystron concepts for CLIC
• 1 GHz, 50 MW pk
• Collaboration with CERN and Thales Electron Devices
• Previous project – Future Linear Collider Klystron Study – Dr Jinjun Feng, Collaboration with CERN, DESY, E2V
Technologies, TMD Technologies.
RF Presentation to CI SAC 23 Nov 2006 12
Energy recovery linac stability for 4GLS
• Emma Wooldridge (ASTeC Staff, PhD Student)
• Prof. Richard Carter
• Susan Smith (ASTeC)
• Study of beam break-up and its prevention
RF Presentation to CI SAC 23 Nov 2006 14
High brightness gun for 4GLS
• Fay Hannon (PhD student) • Dr Rebecca Seviour• Dr Bob Rimmer (JLab)• Project funded and based at JLab
RF Presentation to CI SAC 23 Nov 2006 15
RF vacuum breakdown (Multipactor)
• Dr Rebecca Seviour, Dr Richard Jenkins, Dr Matt Stables, Chris Hill (PhD Student), Prof. Richard Carter
• Theoretical and experimental study of multipactor discharges in complex structures
• Collaboration with E2V Technologies
• Previous project – Multipactor in the CESR RF system, – Dr Philippe Goudket, Professor Richard Carter, Mike Dykes
(ASTeC) – Collaboration with Cornell University
RF Presentation to CI SAC 23 Nov 2006 16
Multipactor – Experimental Work
• Chris Hill (PhD Student) • Prof Richard Carter• Multipactor in a klystron input cavity
RF Presentation to CI SAC 23 Nov 2006 17
Multipactor – Simulation
• Dr Rebecca Seviour• Dr Matt Stables
• Aim – Computer simulation of multipactor in complex geometries
• Issues– Accuracy of fields close to
surfaces– Knowledge of energy spectrum
of secondary electrons
RF Presentation to CI SAC 23 Nov 2006 18
Multipactor – Secondary Electron Emission Measurements
• Dr Richard Jenkins• Prof Richard Carter• Re-commissioning of Auger
spectrometer
E.D.C. for different beam voltages
0
0.5
1
1.5
2
2.5
3
-410 -370 -330 -290 -250 -210 -170 -130 -90 -50 -10
Retarding Potential E
N(E
)
100V150V200V300V400V
Acid cleaned, not outgased Ni SAMPLE, :5 * 10^-8 Torr1st derivative of current (EDC)A1=1KV, A2=200V,A3,A4=Variable10^-9, BW=3, Vac=0.5V Vcoll=250 VFreq=high, Phase shift =+20100SECS 100V SWEEP
RF Presentation to CI SAC 23 Nov 2006 19
Multipactor – prediction of secondary electron emission coefficients
• Dr Rebecca Seviour• Accelrys used to investigate band diagrams of materials
TiN = 1
TiN
Al2O3
Muon Ionisation Cooling for NF & MICE
Need:• 201 MHz Resonant Cavities at 16 MV/w in 4T field• High accuracy measurement of the Eacc
• Dr Rebecca Seviour• 1 x PhD (MICE Phase II)
RF Presentation to CI SAC 23 Nov 2006 21
RF Cavity development
• Dr Rebecca Seviour• 2 x Post Doc’s (NF)
RF Presentation to CI SAC 23 Nov 2006 22
RF Cavity development
Without Magnetic field has achieved 16 MV/m
Electric field Magnetic field Surface currents
Scattering causes losses limits current
limits RF limits acceleration
Metal
Vacuum
Excitation MotionImpurities
RF Presentation to CI SAC 23 Nov 2006 23
We propose to conduct a systematic review of each stage of manufacture.
Investigating the effect each stage has on the surface topology and chemical composition of the surfaces, and ultimately the effect on cavity performance.
• Auger Spectrometry
• Atomic force microscopy
These results will also be compared to theory.
Transport
CodesCavity Q
RF Cavity development
RF Presentation to CI SAC 23 Nov 2006 24
RF Cavity development: Alternatives to EP
Al2O3 suspended in
PH7 Solution.
CMP cheaper & less hazardous than EP.
Only useful on flat areas
Chemical Mechanical Polishing (CMP)
(Rohm and Haas Electronic Materials)
RF Presentation to CI SAC 23 Nov 2006 25
Ra ~ 0.4 m
Abrasive Flow (AF)
RF Cavity development: Alternatives to EP
RF Presentation to CI SAC 23 Nov 2006 26
PBG Based Particle Acceleration
• Dr Rebecca Seviour• 2 x Post Doc’s • 2 x PhD’s• 1 x MSc
RF Presentation to CI SAC 23 Nov 2006 27
• RF Creation
• Particle Acceleration
• Slow-wave structures
• Inverse Cherenkov Acceleration
• Quasi-Crystals/Metamaterials
PBG Based Particle Acceleration
RF Presentation to CI SAC 23 Nov 2006 28
Selected Publications• Carter RG., ‘Accuracy of microwave cavity perturbation measurements’, IEEE Transactions on Microwave Theory
& Techniques, vol.49, no.5, pp.918-23. (2001)
• Geng RL. Padamsee H. Belomestnykh S. Goudket P. Dykes DM. Carter RG., ‘Suppression of multipacting in rectangular coupler waveguides’, Nuclear Instruments & Methods in Physics Research Section A-Accelerators Spectrometers Detectors & Associated Equipment, vol.508, no.3, pp.227-38. (2003)
• Tahir I., Dexter A.C and Carter R.G., ‘Noise Performance of Frequency and Phase Locked CW Magnetrons operated as current controlled oscillators’, IEEE Transactions on Electron Devices, vol.52, no.9, pp.2096-2103, (2005)
• Dexter A.C. and Seviour R. ‘Rapid Generation of Multipactor Charts by Numerical Solution of the Phase Equation’, J. Phys D: Appl. Phys. vol 38, pp1383-1389, (2005)
• Seviour, R. ‘The Role of Elastic and Inelastic Electron Reflection in Multipactor Discharges’, IEEE Transactions on Electron Devices, vol.52, pp.1927-1930, (2005)
• Geng RL, Goudket P, Carter RG, Belomestnykh S, Padamsee H, Dykes DM, Dynamical aspects of multipacting induced discharge in a rectangular waveguide, Nuclear Instruments & Methods in Physics Research Section A-Accelerators Spectrometers Detectors & Associated Equipment, vol.538, pp.189-205, (2005)
• Tahir I., Dexter A.C and Carter R.G., ‘Noise performance of frequency- and phase-locked CW magnetrons operated as current-controlled oscillators’, IEEE Transactions on Electron Devices Volume 3, no.7, pp.1721–1729, (2006)