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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.
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RF Technology Professor Richard Carter Lancaster University Engineering Department 23rd November 2006
Research group focus • Electromagnetics • High power RF and microwave engineering • Particle dynamics in RF electromagnetic fields • Vacuum electronics RF Presentation to CI SAC 23 Nov 2006 Courtesy of Thales Electron Devices
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 Staff RF Presentation to CI SAC 23 Nov 2006
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
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
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
Stabilisation of c.w. magnetron oscillators Free-running magnetron Magnetron with PLL frequency control Magnetron with PLL control and injection • 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 RF Presentation to CI SAC 23 Nov 2006
High Power RF Sources for IFMIF • Prof Richard Carter, Carl Beard • Conceptual design report:1 MW c.w., 175 MHz, 90% efficiency RF Presentation to CI SAC 23 Nov 2006
RF Output Input cavity Anode Collector Output cavity Grid bias and RF Input Cathode Radial inductive output tubes • Sharon Crane (PhD student), • Prof. Richard Carter • Collaboration with E2V Technologies • Target 1 GHz, 1 MW c.w. RF Presentation to CI SAC 23 Nov 2006
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
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
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
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
Multipactor – Experimental Work • Chris Hill (PhD Student) • Prof Richard Carter • Multipactor in a klystron input cavity RF Presentation to CI SAC 23 Nov 2006
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
Multipactor – Secondary Electron Emission Measurements • Dr Richard Jenkins • Prof Richard Carter • Re-commissioning of Auger spectrometer RF Presentation to CI SAC 23 Nov 2006
TiN = 1 TiN Al2O3 Multipactor – prediction of secondary electron emission coefficients • Dr Rebecca Seviour • Accelrys used to investigate band diagrams of materials RF Presentation to CI SAC 23 Nov 2006
Muon Ionisation Cooling for NF & MICE Dr Rebecca Seviour 1 x PhD (MICE Phase II) Need: • 201 MHz Resonant Cavities at 16 MV/w in 4T field • High accuracy measurement of the Eacc
RF Cavity development Dr Rebecca Seviour 2 x Post Doc’s (NF) RF Presentation to CI SAC 23 Nov 2006
RF Cavity development Without Magnetic field has achieved 16 MV/m Electric field Magnetic field Surface currents Vacuum Metal Excitation Motion Impurities Scattering causes losses limits current • limits RF limits acceleration RF Presentation to CI SAC 23 Nov 2006
RF Cavity development 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 Codes Cavity Q RF Presentation to CI SAC 23 Nov 2006
RF Cavity development: Alternatives to EP Chemical Mechanical Polishing (CMP) Al2O3suspended in PH7 Solution. CMP cheaper & less hazardous than EP. Only useful on flat areas (Rohm and Haas Electronic Materials) RF Presentation to CI SAC 23 Nov 2006
RF Cavity development: Alternatives to EP Abrasive Flow (AF) Ra ~ 0.4 m RF Presentation to CI SAC 23 Nov 2006
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
PBG Based Particle Acceleration RF Creation Particle Acceleration Slow-wave structures Inverse Cherenkov Acceleration Quasi-Crystals/Metamaterials RF Presentation to CI SAC 23 Nov 2006
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 DevicesVolume 3, no.7, pp.1721–1729, (2006) RF Presentation to CI SAC 23 Nov 2006