Generation of high power, high frequency radiation using high brightness pseudospark-sourced relativistic electron beams

Lead Research Organisation: University of Strathclyde
Department Name: Physics

Abstract

The principle aim is the investigation of the pseudospark discharge resulting in the generation of electron beam pulses with the highest simultaneous current density and brightness of any known type of electron beam source. Having constructed and operated the first coherent radiation source based on a pseudospark discharge, we have recently measured a high current density (1.5kAcm [-2]) electron beam of brightness 10[11] to 10[12] Am[-2]rad[-2], the proposed programme aims to enhance our understanding of the physics the pseudospark discharge as the size of this plasma cathode is reduced and to produce and transport for the first time small (mm and sub-mm) diameter electron pulses of exceptionally current density and beam quality. The power that can be generated from free electron radiation sources in the hundreds of GHz to THz frequency range has been limited by the fact that as the frequency is increased, the diameter of the interaction has to be reduced in order to prevent the maser becoming overmoded resulting in a loss of the temporal and spatial coherence of the output radiation. The reduction in the size of the interaction region makes it increasingly difficult (if not impossible) using conventional cathodes to focus and form high current density, high quality electron beams through the small size interaction region of a high frequency maser. It is our intention to combine the collective knowledge and expertise of three leading university research groups in the fields of 1) pseudospark physics, 2) computational modelling of millimetre wave sources and design of THz components and 3) advanced millimetre wave manufacturing technologies, to investigate the use of pseudospark sourced electron beam pulses to generate high power, high frequency coherent electromagnetic radiation via the klystron (200GHz) and backward wave (390GHz up to 1THz) instability.

Publications

10 25 50
 
Description To achieve higher BWO output power levels in the hundreds of GHz to THz range, a higher current density electron beam, around the 100s of A/cm2, is required. But as the frequency is increased towards the THz range, the diameter of the BWO interaction region has to be reduced in order to prevent the beam-wave interaction region becoming overmoded which results in a loss of the temporal or spatial coherence of the output radiation. To satisfy the beam requirements for THz devices, the pseudospark-sourced electron beam was used due to it possessing the highest combined beam density and brightness as compared to any other electron beam source. Because of its high current emission and special discharge characteristics it has many useful potential applications such as an electron beam driven X-ray source, THz remote imaging and plasma diagnostics. Theoretical and experimental study is underway of a high power 100GHz Extended Interaction Klystron Oscillator (EIKO) based on planar slow-wave structures using high brightness, pseudospark (PS)-sourced sheet electron beam. The pseudospark-sourced sheet beam driven Extended Interaction Device is capable of being scaled to THz frequencies opening up applications in sub-millimetre wave radar and THz magnetic resonance spectroscopy and spectroscopy of materials.
Exploitation Route The pseudospark source has attracted significant world wide interest due to its ability to generate sheet electron beam with 1.2kW output at ~100GHz without the need to use an axial guide magnetic field as evidenced by a strong collaboration with leading scientists in UESTC, Jiaotong and Schenzen Universities China. It is small, lightweight, portable, cost-effective and capable of operation at room-temperature making it compatible for integration in airborne platforms.
Sectors Agriculture, Food and Drink,Education,Electronics,Environment,Healthcare,Manufacturing, including Industrial Biotechology

 
Description New applications will follow from the high power, sub-THz high frequency pseudospark driven radiation sources in wave radar THz spectroscopy such as remote sensing the health or stress of crops using active terahertz radiation. This can be achieved by installing compact and light-weight broadband terahertz sources with apropriate output power on a drone to irradiate the crops in fields. Terahertz waves can penetrate a certain depth into leaves and the reflected wave from the can be recorded with the amplitude of reflected wave used to characterize and monitor the water level in the crops. An appropriate level of water within the leaves can signal the health of the crops.
First Year Of Impact 2018
Sector Agriculture, Food and Drink,Electronics,Environment,Manufacturing, including Industrial Biotechology
Impact Types Societal,Economic

 
Description Compact ligth weight pseudospark driven THz sources for airborne remote sensing of crops
Geographic Reach Multiple continents/international 
Policy Influence Type Influenced training of practitioners or researchers
 
Description 1 year China Scholarship Council postdoctoral fellowship for Dr Junping Zhao to carry our collaborative research in the ABP group, Departmetn of Physics, University of Strathclyde
Amount £13,800 (GBP)
Funding ID 201506285075 
Organisation University of Leeds 
Department China Scholarship Council
Sector Academic/University
Country United Kingdom
Start 08/2015 
End 09/2016
 
Description 1 year China Scholarship Council postdoctoral fellowship for Dr Yong Yin to carry our collaborative research in the ABP group, Departmetn of Physics, University of Strathclyde
Amount £18,000 (GBP)
Organisation University of Leeds 
Department China Scholarship Council
Sector Academic/University
Country United Kingdom
Start 10/2014 
End 09/2015
 
Description 18 month China Scholarship Council for Guoxiang Shu
Amount £19,800 (GBP)
Funding ID 201506070089 
Organisation University of Leeds 
Department China Scholarship Council
Sector Academic/University
Country United Kingdom
Start 10/2015 
End 04/2017
 
Description 2 year China scholarship council for Gou Liu to carry out PhD studies in the ABP group, university of Strathclyde
Amount £27,600 (GBP)
Organisation University of Leeds 
Department China Scholarship Council
Sector Academic/University
Country United Kingdom
Start 10/2012 
End 09/2014
 
Description Permanent reloaction of mm-wave heads for a mmillimetre wave Vector Network analyser
Amount £230,000 (GBP)
Funding ID 126981EP02114 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 09/2015 
 
Description SHeet Electron beam vacuum eLectronic Devices for the generation of hIGH power THz radiation
Amount £598,368 (GBP)
Funding ID EP/S00968X/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 08/2018 
End 08/2020
 
Title Metal 3D printing 
Description A Klystron multiplier and millimetre wave components for the gyro-TWA were manufactured using 3D printing of silver with performance of components measured using a Vector Network Analyser (VNA). 
Type Of Material Improvements to research infrastructure 
Year Produced 2013 
Provided To Others? Yes  
Impact A new manufacturing technique based on the 3D printing of metal was devised for the construction of millimetre wave components with the performance measured for the first time using a Vector Network Analyser 
 
Title Particle-in-Cell computation modelling techniques 
Description Two different 3D Particle-in-Cell codes MAGIC and CST Particle Studio have been used to model the gyro-TWA with the output of the different codes compared to each other as well as experimental measurement. 
Type Of Material Computer model/algorithm 
Provided To Others? No  
Impact The computational modelling capability of the group was noticed by UK company e2v Ltd who realised the benefit of Strathclyde working more closely with e2v Technologies Uk Ltd on computational modelling their propriety high power microwave sources. 
 
Title VORPAL models are in the process of being developed to mode the pseudosprak discharge 
Description Vsim5.2 has been used to model electron beam propagation in a background plasma in a situation that is typical of a pseudospark plasma filled microwave device. 
Type Of Material Computer model/algorithm 
Year Produced 2015 
Provided To Others? Yes  
Impact The results of the model were provided to vendor of the software Tech X UK Ltd to see if the new updated Vsim7.2 software is capable of modeling the pseudospark discharge breakdown process itself. 
 
Description Collaboration with Prof Xiaodong Chen on pseudospark modelling at Queen Mary University London (QMUL), UK 
Organisation Queen Mary University of London
Department School of Electronic Engineering and Computer Science
Country United Kingdom 
Sector Academic/University 
PI Contribution Prof Chen's group is carrying out modelling of the pseudospark discharge using the Particle In Cell codes. This complements the modelling of the pseudospark electron beam in the background plasma and experiments carried out at Strathclyde.
Collaborator Contribution The QMUL group are modelling the initiation of the PS discharge.
Impact Outputs were in the form of 5 joint University of Strathclyde and QMUL refereed journal papers.
Start Year 2012
 
Description Project partnership with Duke University 
Organisation Duke University
Country United States 
Sector Academic/University 
PI Contribution Duke University worked with the research team and assisted/contributed to the project outcomes
Collaborator Contribution Duke University used state-of-the-art precision-depth deep reactive ion etching (DRIE) of silicon; and fusion-bonding of multiple etched wafers with sub-micron alignment tolerances to construct for the first time a high frequency (200GHz) Klystron Oscillator.
Impact A new manufacturing technique based on DRIE of silicon which is then coated in copper to form fine millimetre wave electron beam wave interacton regions is being developed by Duke University, their industrial partner Logos and by CSIR-CEERI, India.
Start Year 2008
 
Description Project partnership with TMD Technologies Limited 
Organisation TMD Technologies Limited
Country United Kingdom 
Sector Private 
PI Contribution TMD Technologies Limited worked with the research team and assisted/contributed to the project outcomes
Collaborator Contribution TMD advised on the possible use of a pseudospark discharge as an electron beam source in an X-ray baggage screening system.
Impact The secondment of Dr, Craig Robertson to TMD Technologies Ltd occurred via the Impact Acceleration Account 2015 to 2016. Dr. Robertson while working with TMD were able to prepare an ESA: European Space Agency procurement tender AO 1- 8716/16/NL/HK/hh for a "High Power W-Band Travelleing Wave Tube Amplifier" which was awarded to Dr. Kevin Ronald, Department of Physics, University of Strathclyde working in collaboration with TMD Ltd and RAL Space. This two year knowledge exchange procurement grant for €449,999 Euros is for a high power amplifier for satellite to satellite communications.
Start Year 2008
 
Description e2v Scientific Technologies 
Organisation e2v Technologies
Country United Kingdom 
Sector Private 
PI Contribution Computational modelling developed at Strathclyde is now being accessed by e2v Technologies Ltd to model one of their propriety high power microwave sources.
Collaborator Contribution e2v Ltd have seconded one of the computational modellers to their Chelmsford site via the University of Strathclyde's impact acceleration account to develop a particle-in-cell code model of one of the HPM sources
Impact e2v technologies plc ("e2v") is a world leader in the development, manufacture and supply of high power microwave sources and systems. It successfully supplies systems and solutions into the highly competitive global medical, marine and industrial processing sectors. To maintain this position e2v has an ongoing product development programme to maintain the performance, reliability and manufacturability of its products. To maintain its competitive position e2v has a policy of consistently partnering with world leading academic institutions - an essential measure given the high technology capability being developed in emerging markets. e2v therefore needs to maintain a state of the art microwave development capability, at the centre of which will be a modelling capability based on the latest 3D computational toolsets including Vsim and CST Particle Studio. Although e2v has its own in-house capability, it recognises the need to access not only a computation capability but also an expertise base similar to that that resides in the University of Strathclyde ("UoS") Physics Department. The impact associated with the close alignment of an e2v development programme with the computational modelling capability at Strathclyde will maintain, for the UK, a large commercial enterprise serving the world market for high power microwave devices and systems. This tight collaboration between e2v and UoS will also offer the possibility of an increased market share with high impact technology offerings that continue to stay ahead of the solutions offered by competing companies.
Start Year 2014
 
Title Assisting CST Particel studio with the development of models of pseudospark driven Cherenkov masers 
Description CST Particle studio is a 3 D particle in cell code for modelling electron beam wave interactions. CST were interested in developing an upgrade of theiir software to include plasma filled devices 
Type Of Technology Software 
Year Produced 2017 
Impact Experimental measurements from a pseduospark driven Cherenkov maser was forwarded to CST code developer Monica Balk who worked on including the background plasma in the model. A workshop funded by CST is to take place in the Technology and Innovation Centre, University of Strathclyde on the 29th March 2017 to discuss the plasma filled CST particle studio model of the pseudospark driven Cherenkov maser. 
 
Description 2nd Microwaves in Plasmas and Beams Workshop 2016. 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The 2nd Microwaves in Plasmas and Beams (MPB) workshop was held at the Technology and Innovation Centre, University of Strathclyde in Glasgow, on the 12th and 13th of December 2016. The MPB workshop is principally a UK-based international forum in science and technology of microwave diagnostics and microwave heating for magnetic confined plasmas. The meeting was opened by Martin O'Brien from the Culham Centre for Fusion Energy UK, who gave an update on the impressive progress being made with the MAST upgrade and the opportunities for collaboration with university groups.
Year(s) Of Engagement Activity 2015,2016
 
Description India-UK Scientific Seminar (DST-India & Royal Society UK) 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Type Of Presentation keynote/invited speaker
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Participant : Key-note speaker and plenary lectures at conferences : Invited presentation at the India-UK Scientific Seminar (DST-India & Royal Society UK) at CSIR-CEERI, Pilani, India
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India-UK Scientific Seminar (DST-India & Royal Society UK), Pilani

After presentation of pseudospark research at CSIR-CEERI, Pilani, India our Indian colleagues were keen to apply for fellowships from the Indian government to carry out joint collaborative research at the University of Strathclyde
Year(s) Of Engagement Activity 2014
 
Description Invited Seminar at Glasgow University 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact Visitor : Invited talk : Invited Seminar at Glasgow University
.

Physics Department, University of Glasgow
Year(s) Of Engagement Activity 2010
 
Description Invited Seminar at IETE in India, Pseudospark driven mm-wave/THz sources; 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Visitor : Invited talk : Invited seminar: Pseudospark driven mm-wave/THz sources& presented to The Institution of Electronics and Telecommunications Engineers (IETE, India) at the IETE Pilani Centre, Rajasthan, India.

The Institution of Electronics and Telecommunications Engineers (IETE, India)
Year(s) Of Engagement Activity 2014
 
Description Invited Seminar at Physics Department, University of Oxford 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation keynote/invited speaker
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Visitor : Invited talk : Invited Seminar at Oxford University
.

After the presentation colleagues from the Department of Physics University of Oxford were keen to collaborate.
Year(s) Of Engagement Activity 2010,2012,2014
 
Description Invited talk at International Conference on Plasma Science, Technology and Applications (ICPSTA-2016) at Amity School of Applied Sciences, Amity University Uttar Pradesh (AUUP), Lucknow campus, India 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited talk on pseudospark physics at International Conference on Plasma Science, Technology and Applications (ICPSTA-2016) at Amity School of Applied Sciences, Amity University Uttar Pradesh (AUUP), Lucknow campus, India enabled joint research opportunities to be planned.
Year(s) Of Engagement Activity 2016
 
Description Invited talk at National Conference on Vacuum Electronic Devices and Applications, CSIR-CEERi, Pilani India 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited talk on pseudospark physics at VEDA 2012 at the Central Electronics Engineering Research Institute, (CEERI), Pilani, India enabled joint areas of interest in pseudospark between the UK and India to be discussed and explored.
Year(s) Of Engagement Activity 2012
URL http://www.ceeri.res.in/veda/VEDA_2012_Schedule_Final.pdf
 
Description Organised the 14th UK Technological Plasma Workshop 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact The Technological Plasma Workshop was held in Coventry alongside the Vacuum Symposium at the Vacuum Expo at the Ricoh Arena, on the 12th and 13th of October 2016. The Technological Plasma Workshop (TPW) is principally a UK-based international forum in science and technology of plasmas and gas discharges. The workshop based within the wider Vacuum Symposium was used as a form for exploring collaborative opportunities between the academic and industrial communities.
Year(s) Of Engagement Activity 2013,2014,2015,2016,2017
URL http://www.tpw-uk.org/
 
Description Plenary talk at the 2016 IEEE UK-Europe-China Workshop on Millimeter Waves and THz Technologies (IEEE UCMMT 2016) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Study participants or study members
Results and Impact I gave a plenary talk at the 9th IEEE UK-Europe-China Workshop on Millimeter Waves and THz Technologies (IEEE UCMMT 2016) in Qingdao, China during 5-7 September, 2016. It is a unique forum for presenting advances in millimeter waves and THz technologies as well as facilitating collaboration and exchange opportunities between the UK, mainland Europe and China. I gave one of the 4 invited keynote plenary talks titled "Strathclyde millimetre wave and THz source research" in a conference consisting of 110 oral presentation (22 invited papers) in 12 oral sessions and 2 poster sessions. The outcome that has arisen two visiting scientists to Strathclyde, Dr. Junping Zhao from High Voltage Division, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an, China and Dr. Wang Li from the University of Electronic Science and Technology of China, Chengdu, China.
Year(s) Of Engagement Activity 2016
URL http://ucmmt2016.com/
 
Description UK/Europe-China International Workshop 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Keynote/plenary speaker : Key-note speaker and plenary lectures at conferences : Invited keynote paper at UK/Europe-China International Workshop on millimetre-waves and terahertz technologies "Recent Progress in High Power Millimetre-wave Sources at Strathclyde University" 19-21 October 2009 , RAL, UK (Invited Keynote paper also given in the 1st Workshop held in Chengdu, China in 2008)
.

UK/Europe-China International Workshop
Year(s) Of Engagement Activity 2009