Production of Powerful Spatially Coherent Radiation in Planar and Coaxial FEM Exploiting Two-Dimensional Distributed Feedback

Arzhannikov, A. V.; Cross, A. W.; He, Wenlong; Kalinin, P. V.; Konoplev, I. V.; Kuznetsov, S. А.; Peskov, N. Yu.; Phelps, A. D. R.; Robertson, C. W.; Ronald, K.; Sergeev, A. S.; Sinitsky, S. L.; Степанов, В. Д.; Thumm, M.; Whyte, C.G.; Zaslavsky, V. Yu.

doi:10.1109/tps.2009.2027326

Cited by 18 publications

(16 citation statements)

References 22 publications

(42 reference statements)

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“…As a result of this work narrowband microwave generators of. In this experiment effective mode selection over the transverse (azimuthal) index was demonstrated with oversize parameter of the resonators of about 25 wavelengths and output power level of ~ 50 MW were achieved [7].…”

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confidence: 92%

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Powerful free-electron masers with novel Bragg resonators

Peskov¹,

Sergeev²,

Аржанников

et al. 2013

2013 International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves

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High-efficiency Ka-band FEM-oscillator was elaborated during the last few years in collaboration between JINR (Dubna) and IAP RAS (N.Novgorod). A schematic diagram of the JINR-IAP FEM experiments is shown in Fig.1. The induction linac LIU-3000 (JINR), which generates a 0.8 MeV / 200 A / 250 ns electron beam with a repetition rate of 1 Hz, drives the FEM-oscillator. Transverse velocity in the magnetically guided beam is pumped in a helical wiggler of 6 cm period. The main advantages of the JINR-IAP FEM is the use of a reversed guide magnetic field [1], which provides high-quality beam formation in the tapered wiggler section with a low sensitivity to the initial beam spread, alongside with Bragg resonator having a step of phase of corrugation [2], which possesses high electrodynamical mode selection. As a result, stabile single-mode operation with high electron efficiency was achieved in the FEM. At the present stage the FEM generates 20 MW / 200 ns pulses at 30 GHz with the spectrum width of 6 -7 MHz, which is close to the theoretical limit (Fig.2). Stability of the FEM radiation parameters (frequency, output power, pulse shape, etc.) was demonstrated over a sequence of ~ 10 5 pulses.The parameters achieved allow the FEM to be used in several applications. The test facility to study surface heating effects at 30 GHz was constructed based on the FEM source [3]. A special copper cavity was designed to model temperature regime in a high-Q accelerating structure of the CLIC (CERN) project. The profile of the cavity surface was optimized to enhance the RF magnetic field in a certain zone and provide needed temperature rise up to 250°C during each RF-pulse. An electronic microscope image of the cavity surface after irradiation by 6·10 4 pulses is shown in Fig.3. Significant fatigue damage of the surface resulted in appearance of RF-breakdown in the cavity. Currently the JINR-IAP FEM is exploited also in biological application (selective destruction of cancer cells) and studying of micro-objects and nano-clusters. Figure 1. Schematic diagram of Ka-band JINR-IAP FEM. solenoid with reversed guide field orientation helical wiggler linac focusing coils electron beam FEM output section based on Talbot effect Bragg resonator with step of phase of corrugation 31 978-1-4799-1068-7/13/$31.00 ©2013 IEEE

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confidence: 92%

“…At previous stage of these experiments the operation of 4-mm single channel planar FEM with 2D distributed feedback was studied [7]. At the present stage we designed two-channel planar FEM driven by two parallel sheet beams.…”

mentioning

confidence: 99%

Powerful free-electron masers with novel Bragg resonators

Peskov¹,

Sergeev²,

Аржанников

et al. 2013

2013 International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves

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“…Taking the matched boundary conditions at both ends of the reflector, one can solve the coupled equations for each mode by using finite differential method or the eigenvector method [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Here the reflectivity for the i-th mode is defined as the ratio of the backward-wave power of the i-th mode to the forward-wave power of the operating mode at input port of the reflector.…”

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confidence: 99%

Effect of Ripple Taper on Coupling Modes in a Coaxial Bragg Structure

Ding

Liu

2010

J Infrared Milli Terahz Waves

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Based on the mode-coupling method, numerical analysis is presented to demonstrate the influence of ripple taper on coupling modes on the frequency response in a coaxial Bragg structure. Results show that the interval between the band-gaps of the competing mode and the desired working mode is narrowed by use of a positive taper, but is expanded if a negative taper is employed, and the influence of the negative taper is more obviously advantage than the positive taper. The residual side-lobes of the frequency response on coupling modes can be effectively suppressed by employing the windowingfunction technique. These characteristics of a tapered coaxial Bragg structure are favorable to improvement of the performance as a reflector or a filter in its application, also favorable to the mode selectivity and further weaken the excitation of unwanted spurious modes.

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“…Such 2D feedback can be realized in planar and co-axial 2D Bragg resonators having double-periodic corrugations of side walls (either similar modulation of dielectric constant). Spatially-extension over one of the transverse coordinates interaction space allows significant increase of the total microwave power (up to GW powers) while keeping power and current densities at moderate level.Experimental studies of FEMs based on this novel feedback mechanism are performed in Ka-band (coaxial geometry) at the University of Strathclyde [3][4][5] and in W-band (planar geometry) at the Budker Institute of Nuclear Physics (Novosibirsk) [6,7] in collaboration with the Institute of Applied Physics RAS (N.Novgorod). As a result of this work narrowband microwave generators of multi-MW power level were realized.…”

mentioning

confidence: 99%

“…Experimental studies of FEMs based on this novel feedback mechanism are performed in Ka-band (coaxial geometry) at the University of Strathclyde [3][4][5] and in W-band (planar geometry) at the Budker Institute of Nuclear Physics (Novosibirsk) [6,7] in collaboration with the Institute of Applied Physics RAS (N.Novgorod). As a result of this work narrowband microwave generators of multi-MW power level were realized.…”

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confidence: 99%

Masers and lasers with two-dimensional distributed feedback

Ginzburg

2009

2009 34th International Conference on Infrared, Millimeter, and Terahertz Waves

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A two-dimensional distributed feedback is an effective method of producing ultra-high power spatially-coherent radiation from an active media, that is spatially extended along two coordinates, including relativistic electron beams with sheet and annular geometry. The present paper describes progress in the investigations of planar and coaxial FEMs based on the novel feedback mechanism. The effective transverse (azimuthal) mode selection has been demonstrated under the transverse size of about 20 -25 wavelengths and narrow-frequency multi-MW microwave pulses have been generated in the Ka-and W-bands.For an active media, that is spatially extended along two co-ordinates including relativistic electron beams with sheet and annular geometry as well laser media, the use of two-dimensional (2D) distributed feedback is beneficial for providing spatial coherence of the radiation and, thus, can be used to increase the total radiation power [1,2]. Such 2D feedback can be realized in planar and co-axial 2D Bragg resonators having double-periodic corrugations of side walls (either similar modulation of dielectric constant). Spatially-extension over one of the transverse coordinates interaction space allows significant increase of the total microwave power (up to GW powers) while keeping power and current densities at moderate level.Experimental studies of FEMs based on this novel feedback mechanism are performed in Ka-band (coaxial geometry) at the University of Strathclyde [3][4][5] and in W-band (planar geometry) at the Budker Institute of Nuclear Physics (Novosibirsk) [6,7] in collaboration with the Institute of Applied Physics RAS (N.Novgorod). As a result of this work narrowband microwave generators of multi-MW power level were realized. In this experiment effective mode selection over the transverse (azimuthal) index was demonstrated with oversize parameter of the resonators of about 25 wavelengths. The present paper is devoted to the results of simulations and experimental studies of above FEMs. I. MODELING AND EXPERIMENTAL STUDIES OF PLANAR 75 GHZ FEM WITH HYBRID BRAGG RESONATORThe 2D distributed feedback is based on the mutual scattering of the four partial wave fluxes ( t i ihx ihx ihz ihz e e e e e E E B B A A Re 0 , (1) where two fluxes (A ± ) propagate in forward and backward (in respect with the electron beam propagation) ±z directions and two other fluxes (B ± ) propagating in the transverse ±x directions act to synchronize different parts of the sheet electron beam. This scattering scheme is realized at planar 2D Bragg structures having double-periodical corrugation of the metal plates 2 2 2 cos ( ) cos ( ) 4 D D D a a h z x h z x ,where 2D a is the corrugation depth The efficient scattering of partial waves (1) takes place under the Bragg resonance condition 2D h h .In this section we describe the results of investigations of a 75 GHz planar FEM. To demonstrate the operability of the novel feedback mechanism, a sheet beam with a transverse size of about 20 wavelengths was used.Fig 1 Scheme of FEM with a hybr...

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Production of Powerful Spatially Coherent Radiation in Planar and Coaxial FEM Exploiting Two-Dimensional Distributed Feedback

Cited by 18 publications

References 22 publications

Powerful free-electron masers with novel Bragg resonators

Powerful free-electron masers with novel Bragg resonators

Effect of Ripple Taper on Coupling Modes in a Coaxial Bragg Structure

Masers and lasers with two-dimensional distributed feedback

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