High power millimetre wave amplifiers for accelerators and magnetic resonance spectroscopy

Lead Research Organisation: University of Strathclyde
Department Name: Physics


A high power millimetre wave Gyrotron Klystron amplifier relevant to accelerators and magnetic resonance spectroscopy will be studied. Gyro-klystrons are well suited to high frequency (36GHz), high power (~MWs) millimetre wave production due to the very high gain (~40dB) possible which mitigates the demands on the input source. The input and output resonators of the gryoklystron will be designed and simulated using electromagnetic simulation software. The electron beam wave interaction will be modelled using particle in cell codes. An amplifier which offers an instantaneous bandwidth ~1% that is capable of supporting complex modulation schemes will be explored.


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Burt G (2017) A Millimeter-Wave Klystron Upconverter With a Higher Order Mode Output Cavity in IEEE Transactions on Electron Devices

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Wang L (2018) Design of a Ka-band MW-level high efficiency gyroklystron for accelerators in IET Microwaves, Antennas & Propagation

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Zhang L (2020) Magnetron Injection Gun for High-Power Gyroklystron in IEEE Transactions on Electron Devices

Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509760/1 01/10/2016 30/09/2021
1974175 Studentship EP/N509760/1 01/10/2017 30/06/2021 Laurence Nix
Description A gyroklystron, which is a high-power microwave amplifier, is being designed. Simulations predict that the amplifier can achieve the required output power
The finalised design will be appropriate for applications in an X-band linear accelerator, where 48GHz linearising cavities could be used to correct for problematic effects of the main 12GHz drive frequency. The frequency band around 48GHz has previously been unexplored, so demonstrating an efficient device at this frequency is significant.
The primary simulation results are complete, displaying good performance of the amplifier, its beam-source, and several input and output components. Two peer-reviewed papers have been published, and a presentation at a peer-reviewed conference is scheduled for the near future. Further study continues to obtain additional results for a deeper model.
Exploitation Route When the simulated design phase is complete, the gyroklystron must be prototyped and undergo physical study. After that stage, the gyroklystron will be of great interest to the research programmes working toward new linear accelerators as it could be appropriate as a component for the associated linearisers.
Sectors Other

Description CompactLight
Amount € 2,999,500 (EUR)
Funding ID H2020-INFRADEV-2016-2017, Grant Agreement number -777431 - XLS 
Organisation European Union 
Sector Public
Country European Union (EU)
Start 01/2018 
End 12/2020
Title CST Microwave Particle Studio modelling of high power gyrotron amplifiers 
Description A CST particle studio modelling of high power gyrotron amplifiers has been improved 
Type Of Material Improvements to research infrastructure 
Year Produced 2020 
Provided To Others? No  
Impact A new CTS Particle Studio techniques was developed to model high power gyrotron amplifiers 
Description Horizon 2020 project CompactLight 
Organisation European Organization for Nuclear Research (CERN)
Country Switzerland 
Sector Academic/University 
PI Contribution Linear theory, non-linear theory and Particle-In-Cell simulations were used to design a three cavity 36GHz gyro-klystron of gain 39dB that is capable of producing 3.2MW of power corresponding to an efficiency of 43% at a PRF of 1kHz. Analysis of the phase stability of the amplifier found that 0.34 degree phase stability can be achieved for a variation in modulator voltage of 0.01%. The 36GHz gyro-klystron designed was compared to previously published gyro-klystron experiments. It was concluded that the 36GHz gyro-klystron when driven by a K100 (150kV, 50A) Scandinova modulator was a viable power source for a high-harmonic lineariser in a soft and hard X-ray Free Electron Laser. The high harmonic lineariser is required to mitigate unavoidable nonlinearities in the FELs electron bunch's energy profile introduced by the Linac accelerating fields.
Collaborator Contribution H2020 project CompactLight is a collaborative project to design a hard X-ray FEL facility beyond today's state of the art, using the latest concepts for bright electron photo injectors, very high-gradient X-band structures operating at 12 GHz, and innovative compact short-period undulators. Compared with existing facilities, the CompactLight design focused on i. benefiting from a lower electron beam energy, due to the enhanced undulator performance, ii. being significantly more compact, as a consequence of the lower beam energy and the high gradient of the X-band structures, iii. being more efficient with less power consumption, as a consequence of the lower energy and the use of higher frequency structures. Project partners consisted of 24 world-leading institutes across Europe and beyond contributing to the 3 objectives above: disseminating X-band technology as a new standard for accelerator-based facilities and advance undulators for the next generation of compact soft and hard X-ray FELs.
Impact During the past decades Synchrotron Radiation facilities have seen an impetuous growth as a fundamental tool for the study of materials in a wide spectrum of sciences, technologies, and applications. The latest generation of light sources, the Free Electron Lasers, capable of delivering high-intensity photon beams of unprecedented brilliance and quality, provide a substantially novel way to probe matter and have very high, largely unexplored, potential for science and innovation. Currently, the FELs operating in EU are three, FERMI, FLASH and FLASH II, operating in the soft X-ray range and two are under commissioning, SwissFEL and EuroXFEL, which will operate in the hard X-ray scale. While most of the worldwide existing FELs use conventional normal conducting 3 GHz S-band linacs, others use newer designs based on 6 GHz C-band technology, increasing the accelerating gradient with an overall reduction of the linac length and cost. CompactLight is multi-disciplinary gathering the world-leading experts in these domains, to achieve two objectives: disseminate X-band technology and associated sub-systems such as Ka-band linearisers as a new standard for accelerator-based facilities and advance undulators to the next generation of compact photon sources, with the aim of facilitating the widespread development of X-ray FEL facilities across and beyond Europe by making them more affordable to build and to operate.
Start Year 2018
Description Invited talk at 13th workshop on breakdown science and high gradient accelerator technology, HG2021 organised by Prof Sami Tantawi (SLAC), USA 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact The design of a 3MW, 36GHz (ka-band) gyrotron klystron to drive a high harmonic lineariser cavity is to be presented to the HGA community which has strong industrial representation from CPI Inc, USA on of the main suppliers of high power microwave amplifiers for accelerator applications. The Ka-band gyro-klystron has also been presented to representatives from ScandiNova the suppliers of the modulator required to drive the gyrotron klystron.
Year(s) Of Engagement Activity 2021
URL https://indico.fnal.gov/event/22025/overview