Publications by Ivan Konoplev


A tunable source of coherent terahertz radiation driven by the microbunched electron beam

Journal of Physics D: Applied Physics IOP Publishing 53 (2020) 105501-105501

H Zhang, I Konoplev, G Doucas


Resonant Excitation of Volume and Surface Fields on Complex Electrodynamic Surfaces

Physical Review Applied 11 (2019)

AJ MacLachlan, CW Robertson, IV Konoplev, AW Cross, ADR Phelps, K Ronald

© 2019 authors. Published by the American Physical Society. Analytical, numerical, and experimental studies of volume and surface-field coupling in planar metal periodic surface lattice (PSL) structures superimposed on dielectric substrates with a metallic backing (PSLDM) are presented. We show the formation of frequency-locked PSLDM-coupled eigenmodes and unlocked surface-field resonances (PSL without substrate). These experimental observations are in excellent agreement with theoretical and numerical predictions. For the first time, the derivation of a field coupling coefficient α is demonstrated. By comparing theoretical and numerical dispersions, we obtain α. Detailed analysis of possible scattering mechanisms and dispersive behavior in subwavelength "effective metadielectric" PSLs is shown. The theory and measurements presented in this paper are applicable over a broad frequency range from optical frequencies to THz and are fundamental to the innovation of high-power short-wavelength sources, solar cells, and alternative subwavelength absorbers.


OPTIMIZATION OF DUAL AXIS ASYMMETRIC CAVITY FOR ENERGY RECOVERY LINAC

(2019)

Y Shashkov, A Bulygin, MA Gusarova, IV KONOPLEV, F Marhauser, A Seryi


Developing Innovative, Robust and Affordable Medical Linear Accelerators for Challenging Environments.

Clinical oncology (Royal College of Radiologists (Great Britain)) (2019)

M Dosanjh, A Aggarwal, D Pistenmaa, E Amankwaa-Frempong, D Angal-Kalinin, S Boogert, D Brown, M Carlone, P Collier, L Court, A Di Meglio, J Van Dyk, S Grover, DA Jaffray, C Jamieson, J Khader, I Konoplev, H Makwani, P McIntosh, B Militsyn, J Palta, S Sheehy, SC Aruah, I Syratchev, E Zubizarreta, CN Coleman


Self-injection of multiple electron microbunches into a beam-driven plasma bubble

45th EPS Conference on Plasma Physics, EPS 2018 2018-July (2019) 893-896

Z Lécz, A Andreev, A Seryi, I Konoplev, J Smith


Studies of high order modes in asymmetric dual-axis cavity

Applied Physics Letters 113 (2018)

M Topp-Mugglestone, IV Konoplev, H Zhang, A Seryi

© 2018 Author(s). Electron-beam current in superconducting radiofrequency energy recovery linear accelerators (SCRF ERLs) is limited by beam break-up (BBU) instabilities disrupting beam transport and energy recuperation. The instabilities originate from the accumulation of high order modes (HOMs) in the cavity and positive feedback between the beam and HOMs which is especially evident in multi-pass ERLs. Overcoming the beam current limitations due to BBU instabilities is one of the challenges in accelerator science. A dual-axis asymmetric SCRF ERL has been proposed as a possible way to drive a high average current electron beam for next-generation light sources and beam cooling in electron-ion colliders (EICs). In this work, detailed studies on HOMs in the asymmetric dual axis cavity were carried out. The asymmetric field distribution of HOMs (i.e., confinement to one or another axis) has been demonstrated and their excitation from different axes has been studied. The results confirm the numerical predictions and theory developed to describe the asymmetric dual axis cavity.


Trains of electron micro-bunches in plasma wake-field acceleration

PLASMA PHYSICS AND CONTROLLED FUSION 60 (2018) ARTN 075012

Z Lecz, A Andreev, I Konoplev, A Seryi, J Smith


Millimeter-Wave Periodic Surface Lattices for Mode Control in Vacuum Electronic Sources

2017 EIGHTEENTH INTERNATIONAL VACUUM ELECTRONICS CONFERENCE (IVEC) (2018)

AJ MacLachlan, AR Phipps, CW Robertson, IV Konoplev, K Ronald, AW Cross, ADR Phelps, IEEE


Selective excitation and control of coherent terahertz Smith-Purcell radiation by high-intensity period-tunable train of electron micro-bunches

APPLIED PHYSICS LETTERS 113 (2018) ARTN 171104

Y Liang, Y Du, D Wang, L Yan, Q Tian, K Chen, W Huang, C Tang, IV Konoplev, H Zhang, G Doucas


PERIODIC STRUCTURES MANUFACTURED BY 3D PRINTING FOR ELECTRON BEAM EXCITATION OF HIGH POWER MICROWAVE SOURCES

2017 IEEE 21ST INTERNATIONAL CONFERENCE ON PULSED POWER (PPC) (2018)

AR Phipps, AJ MacLachlan, L Zhang, CR Robertson, IV Konoplev, K Ronald, ADR Phelps, AW Cross, IEEE


Concept of a tunable source of coherent THz radiation driven by a plasma modulated electron beam

PHYSICS OF PLASMAS 25 (2018) ARTN 043111

H Zhang, IV Konoplev, G Doucas, J Smith


OPTIMIZATION OF DUAL AXIS ASYMMETRIC CAVITY FOR ENERGY RECOVERY LINAC

29th Linear Accelerator Conf. (2018)

Y Shashkov, A Bulygin, MA Gusarova, IV KONOPLEV, F Marhauser, A Seryi


Observation of coherent Smith-Purcell and transition radiation driven by single bunch and micro-bunched electron beams

APPLIED PHYSICS LETTERS 112 (2018) ARTN 053501

Y Liang, Y Du, X Su, D Wang, L Yan, Q Tian, Z Zhou, D Wang, W Huang, W Gai, C Tang, IV Konoplev, H Zhang, G Doucas


Novel grating designs for a single-shot Smith-Purcell bunch profile monitor

Proceedings of the 5th International Beam Instrumentation Conference, IBIC 2016 (2018) 213-216

AJ Lancaster, G Doucas, H Harrison, IV Konoplev

Copyright © 2016 CC-BY-3.0 and by the respective authors. Smith-Purcell radiation has been successfully used to perform longitudinal profile measurements of electron bunches with sub-ps lengths [1]. These measurements require radiation to be generated from a series of gratings to cover a sufficient frequency range for accurate profile reconstruction. In past systems the gratings were used sequentially and so several bunches were required to generate a single profile, but modern accelerators would benefit from such measurements being performed on a bunch by bunch basis. To do this the radiation from all three gratings would need to be measured simultaneously, increasing the mechanical complexity of the device as each grating would need to be positioned individually and at a different azimuthal angle around the electron beam. Investigations into gratings designed to displace the radiation azimuthally will be presented. Such gratings could provide an alternative to the rotated-grating approach, and would simplify the design of the single-shot monitor by reducing the number of motors required as all of the gratings could be positioned using a single mount.


A Fabry-Pérot interferometer with wire-grid polarizers as beamsplitters at terahertz frequencies.

The Review of scientific instruments 89 (2018) 035116-

H Harrison, AJ Lancaster, IV Konoplev, G Doucas, A Aryshev, M Shevelev, N Terunuma, J Urakawa, PG Huggard

The design of a compact Fabry-Pérot interferometer (FPi) and results of the experimental studies carried out using the device are presented. Our FPi uses freestanding wire-grid polarizers (WGPs) as beamsplitters and is suitable for use at terahertz (THz) frequencies. The FPi was studied at the LUCX facility, KEK, Japan, and an 8 MeV linear electron accelerator was used to generate coherent Smith-Purcell radiation. The FPi was designed to be easy to align and reposition for experiments at linear accelerator facilities. All of the components used were required to have a flat or well understood frequency response in the THz range. The performance of the FPi with WGPs was compared to that of a Michelson interferometer and the FPi is seen to perform well. The effectiveness of the beamsplitters used in the FPi is also investigated. Measurements made with the FPi using WGPs, the preferred beamsplitters, are compared to measurements made with the FPi using silicon wafers as alternative beamsplitters. The FPi performs well with both types of beamsplitter in the frequency range used (0.3-0.5 THz). The successful measurements taken with the FPi demonstrate a compact and adaptable interferometer that is capable of analyzing THz radiation over a broad frequency range. The scheme is particularly well suited for polarization studies of THz radiation produced in an accelerator environment.


Smith-Purcell coherent THz radiation signal modulation measurements for monitoring of separation of femtosecond electron micro-bunches

International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz (2017)

IV Konoplev, H Zhang, AJ Lancaster, H Harrison, G Doucas, A Aryshev, M Shevelev, N Terunuma, J Urakawa

© 2017 IEEE. Micro-bunched particle beams are used for a wide range of research including tunable sources of THz radiation. In most of the applications accurate and non-destructive monitoring of the bunch-to-bunch separation is required. We present the results of proof-of-principle experiments on measuring the distance between two micro-bunches via the analysis of the coherent Smith-Purcell signal amplitude modulation. The proposed monitor can be used to provide feedback to control the sum-millimeter distances between the femtosecond long micro-bunches to stabilize the operation of a THz oscillator or to position the witness bunch into the right phase of the wakefield.


Non-destructive measurement and monitoring of separation of charged particle micro-bunches

APPLIED PHYSICS LETTERS 111 (2017) ARTN 043505

H Zhang, IV Konoplev, AJ Lancaster, H Harrison, G Doucas, A Aryshev, M Shevelev, N Terunuma, J Urakawa


Experimental studies of 7-cell dual axis asymmetric cavity for energy recovery linac

PHYSICAL REVIEW ACCELERATORS AND BEAMS 20 (2017) ARTN 103501

IV Konoplev, K Metodiev, AJ Lancaster, G Burt, R Ainsworth, A Seryi


Smith-Purcell coherent THz radiation signal modulation measurements for monitoring of separation of femtosecond electron micro-bunches

2017 42nd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) IEEE (2017)

IV Konoplev, H Zhang, AJ Lancaster, H Harrison, G Doucas, A Aryshev, M Shevelev, N Terunuma, J Urakawa


Electron beam excitation of coherent sub-terahertz radiation in periodic structures manufactured by 3D printing

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS 402 (2017) 202-205

AR Phipps, AJ MacLachlan, CW Robertson, L Zhang, IV Konoplev, AW Cross, ADR Phelps

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