Particle-in-cell simulation of second and third harmonic cavity klystron

Hill, Victoria C. R.; Constable, D. A.; Lingwood, Chris; Marrelli, C.; Syratchev, Igor

doi:10.1109/ivec.2017.8289626

Cited by 12 publications

(3 citation statements)

References 4 publications

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“…The second harmonic bunching method has been applied in most high power UHF CW klystrons successfully. [5] The other bunching methods are being validated in laboratory such as the bunchingalignment-collection (BAC), [6] the core stabilization method (CSM), [7] and the core oscillation method (COM). [8] Due to lack of design and manufacturing experience of the UHF high power CW klystron in China, the R & D of CEPC klystron is divided into three phases.…”

Section: Introductionmentioning

confidence: 99%

Design and high-power test of 800-kW UHF klystron for CEPC

Xiao¹,

Fukuda²,

Zhou³

et al. 2022

Chinese Phys. B

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To reduce the energy demand and operation cost for circular electron positron collider (CEPC), the high efficiency klystrons are being developed at Institute of High Energy Physics, Chinese Academy of Sciences. A 800-kW continuous wave (CW) klystron operating at frequency of 650-MHz has been designed. The results of beam–wave interaction simulation with several different codes are presented. The efficiency is optimized to be 65% with a second harmonic cavity in three-dimensional (3D) particle-in-cell code CST. The effect of cavity frequency error and mismatch load on efficiency of klystron have been investigated. The design and cold test of reentrant cavities are described, which meet the requirements of RF section design. So far, the manufacturing and high-power test of the first klystron prototype have been completed. When the gun operated at DC voltage of 80 kV and current of 15.4 A, the klystron peak power reached 804 kW with output efficiency of about 65.3% at 40% duty cycle. The 1-dB bandwidth is ±0.8 MHZ. Due to the crack of ceramic window, the CW power achieved about 700 kW. The high-power test results are in good agreement with 3D simulation.

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Section: Introductionmentioning

confidence: 99%

Design and high-power test of 800-kW UHF klystron for CEPC

Xiao¹,

Fukuda²,

Zhou³

et al. 2022

Chinese Phys. B

View full text Add to dashboard Cite

show abstract

“…In some cases, at high frequencies, to improve the bunching quality a few coupled cells are used instead of a single cavity to enhance the impedance [3,4]. Another important measure that allows the improvement of the klystron efficiency and the reduction of the RF bunching circuit length is the use of harmonic cavities [5,6]. A multicell second harmonic RF circuit was implemented through the design of 12GHz, 50MW high efficiency klystron [7,8].…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Resonant Multipolar Instabilities in High Power Klystrons

Cai

Syratchev

2021

IEEE Trans. Electron Devices

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The monopole monotron instability is a well-known phenomenon in the linear beam devices. In recent development of a high efficiency 50 MW X-band klystron such instabilities were found and mitigated in a special 2 nd harmonic multi-cell cavities triplet that is used to improve the klystron performance. In further simulations of the klystron, using 3D Particle-In-cell computer code, the more rare and complicated phenomenon, previously unreported in non-relativistic devices, associated with rotating multipolar monotron instabilities was discovered. In this letter, the qualitative and quantitative analysis of these oscillations will be presented. Various resonant multipolar instabilities suppression strategies will be introduced and discussed in detail.

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“…1(c) adopting the recently developed bunching process improvements, such as core oscillation method (COM), bunch-aligncompress (BAC), and core stabilization method (CSM). [4] Generally, the klystron is an amplifier of A to B class operation, but it is possible to have a higher efficiency by employing more cavities with 2nd and 3rd harmonics. Prior to building the tube, the manufacturing of the window itself must be performed and evaluated using the existing RF power source to ensure the power handling capability.…”

Section: Introductionmentioning

confidence: 99%

Design and development of radio frequency output window for circular electron–positron collider klystron

Fukuda

Zhou

et al. 2018

Chinese Phys. B

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This paper presents the first phase of design, analysis, and simulation for the klystron coaxial radio frequency (RF) output window. This study is motivated by 800 kW continuous wave (CW), 650 MHz klystrons for the future plan of circular electron-positron collider (CEPC) project. The RF window which is used in the klystron output section has a function to separate the klystron from the inner vacuum side to the outside, and high RF power propagates through the window with small power dissipation. Therefore, the window is a key component for the high power klystron. However, it is vulnerable to the high thermal stress and multipacting, so this paper presents the window design and analysis for these problems. The microwave design has been performed by using the computer simulation technology (CST) microwave studio and the return loss of the window has been established to be less than −90 dB. The multipacting simulation of the window has been carried out using MultiPac and CST particles studio. Through the multipacting analysis, it is shown that with thin coating of TiN, the multipacting effect has been suppressed effectively on the ceramic surface. The thermal analysis is carried out using ANSYS code and the temperature of alumina ceramic is lower than 310 K with water cooling. The design result successfully meets the requirement of the CEPC 650 MHz klystron. The manufacturing and high power test plan are also described in this paper.

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Particle-in-cell simulation of second and third harmonic cavity klystron

Abstract: This paper outlines the results obtained from Magic software for the CSM_23 (Core Stabilization Method) klystron. This klystron implements the use of a second and third harmonic klystron to increase the efficiency. From the PIC simulation an efficiency of 78.1% was achieved.

Cited by 12 publications

References 4 publications

Design and high-power test of 800-kW UHF klystron for CEPC

Design and high-power test of 800-kW UHF klystron for CEPC

Numerical Analysis of Resonant Multipolar Instabilities in High Power Klystrons

Design and development of radio frequency output window for circular electron–positron collider klystron

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