This paper details the development and testing of the first working prototype of the S-band high-power klystron,accomplished at the Budker Institute of Nuclear Physics,Siberian Branch,Russian Academy of Sciences(BINP ...This paper details the development and testing of the first working prototype of the S-band high-power klystron,accomplished at the Budker Institute of Nuclear Physics,Siberian Branch,Russian Academy of Sciences(BINP SB RAS).Upon testing,the klystron demonstrated the following parameters:an operating frequency of 2856 MHz and a peak power output of 50 MW.The paper presents the klystron's design,its constituent units,and pertinent processing procedures,along with discussions on the measurement of its parameters.展开更多
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 f...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 d B. 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.展开更多
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-k...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-k W 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 k V and current of 15.4 A, the klystron peak power reached 804 k W with output efficiency of about 65.3% at 40% duty cycle. The 1-d B 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.展开更多
This letter reports the development of a 50MW S-band klystron in the Institute of Electronics, Chinese Academy of Sciences （IECAS）. It adopted a structure of six-cavity and single output window. Under conditions of ...This letter reports the development of a 50MW S-band klystron in the Institute of Electronics, Chinese Academy of Sciences （IECAS）. It adopted a structure of six-cavity and single output window. Under conditions of an RF （Radio Frequency） pulse width of 4t, ts, a beam voltage of 305,9kV and a beam current of 368A, the peak output power has achieved 51.4MW with an efficiency of 45.6% and a gain of 54dB.展开更多
Two methods for improving the equidriving power-frequency characteristics of broad-band high power klystrons are presented. One is that a comb-line bandpass filter with someattenuation properties is inserted between t...Two methods for improving the equidriving power-frequency characteristics of broad-band high power klystrons are presented. One is that a comb-line bandpass filter with someattenuation properties is inserted between the TWT driver and the klystron for compensatingthe gain-frequency characteristics of the klystron to get the required equidriving power-frequencycharacteristics. The other is that a reactive element is connected with the input cavity to changeits resonance frequencies f<sub>0</sub> and Q<sub>L</sub>, and thus to improve the power-frequency characteristics ofthe klystron.展开更多
The paper introduces the -35 kV/200 kW high voltage power supply (HVPS) which is specially used to test klystron units in LHCD system. The new klystrons must be tested under high voltage level before operation and the...The paper introduces the -35 kV/200 kW high voltage power supply (HVPS) which is specially used to test klystron units in LHCD system. The new klystrons must be tested under high voltage level before operation and the old klystrons which have worked for a longtime must be exercised by HVPS in lower hybrid current drive (LHCD) system. As the former HVPS has some shortages in engineering design and operation design, the HVPS has to be modified and rebuilt by adopting new method and technology to solve existing bottle-neck problems.展开更多
The paper mainly presents the design of beam-wave interaction of a C-band high-peakpower high-efficiency broadband klystron.The beam-wave interaction section is designed based on considerations of efficiency and bandw...The paper mainly presents the design of beam-wave interaction of a C-band high-peakpower high-efficiency broadband klystron.The beam-wave interaction section is designed based on considerations of efficiency and bandwidth synthetically.As a part of beam-wave interaction section,buncher section is simulated by Particle-In-Cell(PIC) code to observe the bunching process of electron beam to achieve high conversion efficiency of electron beam and RF field.When it comes to the other part,output circuit is designed as a three-section filter by an output cavity loaded with Chebyshev filter,and the cold test results are given.The beam-wave interaction is simulated by EGUN code and Arsenal-MSU code respectively.The simulated results indicated that,the existence of power dips in the operating bandwidth is verified by Arsenal-MSU code,comparing proper results by EGUN code.Then,the method that design parameters are not adjusted except parameters of buncher cavities to remove potential power dips is described.What is more,the simulated results of electron optics system are given by EGUN code and Arsenal-MSU code respectively.The further hot test results of klystron prove that the whole design of beam-wave interaction is effective.展开更多
This paper describes a high security data transmission system over X-band microwave frequency. The paper has two parts. The first part deals with encryption of binary data by Advanced Encryption Standard (AES) using V...This paper describes a high security data transmission system over X-band microwave frequency. The paper has two parts. The first part deals with encryption of binary data by Advanced Encryption Standard (AES) using VHDL modeling of Field Programmable Gate Array (FPGA). The second part deals with a novel idea of transmitting the encrypted data by using a single klystron. This requires the simultaneous generation of a pair of two independent RF frequencies from a reflex klystron working for X-band frequency range. In this scheme, the klystron is suitably biased on the repeller terminal and superimposed on a train of AES encrypted binary data so as to create two RF frequencies one corresponding to negative peaks and the other one to the positive peaks of the data resulting in an Frequency Shift Keying (FSK) signal. The results have been verified experimentally.展开更多
This letter introduces the design ideas, simulation and test results of an S-band klystron with bandwidth of 11%, which was developed by the Institute of Electronics, Chinese Academy of Sciences (IECAS). On the peak p...This letter introduces the design ideas, simulation and test results of an S-band klystron with bandwidth of 11%, which was developed by the Institute of Electronics, Chinese Academy of Sciences (IECAS). On the peak power level of 800 kW, the efficiency of klystron is more than 30%; the gain is more than 41 dB; the equal-driving relative instantaneous bandwidth is over 11%; the average power is larger than 8 kW, and the power fluctuation within bandwidth is less than 1.5 dB.展开更多
Recent research progresses in Multi-Beam Klystron (MBK) in IECAS are briefly introduced in the letter. The S-band MBKs of IECAS have peak power of 120-250 kW, average power of 4-9 kW, efficiency of 35-45%, gain of 41-...Recent research progresses in Multi-Beam Klystron (MBK) in IECAS are briefly introduced in the letter. The S-band MBKs of IECAS have peak power of 120-250 kW, average power of 4-9 kW, efficiency of 35-45%, gain of 41-46 dB, beam voltage of 15-19 kV, and weight of 40-45 kg. Some key technical problems of MBK are also described and discussed. Among them,improving the design of MBK to obtain the required bandwidth, raising beam transmission to increase average power, eliminating oscillation and spray spectrum, overcoming window breakdown caused by magic mode, reducing breakdown times of electrongun, are most important things for the practical MBK. Besides, further research work in MBK in IECAS is commented.展开更多
To carry out lower hybrid wave heating and current drive plasma experiment on tokamak, we need mega-watt order of microwave power generated by the parallel-running klystrons. Those klystrons must be driven by the micr...To carry out lower hybrid wave heating and current drive plasma experiment on tokamak, we need mega-watt order of microwave power generated by the parallel-running klystrons. Those klystrons must be driven by the microwave exciter. Now our microwave exciter is used for many years and its performance is decreased very much. It can not satisfy any more the hybrid wave heating and current drive plasma experiment. So we set out to design a new microwave exciter that is consist of the microwave solid components, amplitudestabilization control, modularization design with multitude-outputs, microwave phase control in order to satisfy the demand of the different work in the hybrid wave heating and current drive plasma experiment.展开更多
The measured fields of the optical klystron in NSRL (National Sy-chrotron Radiation Laboratory) are given, including the distribution on the axis, and the integrated field distribution. The harmonic magnet field and t...The measured fields of the optical klystron in NSRL (National Sy-chrotron Radiation Laboratory) are given, including the distribution on the axis, and the integrated field distribution. The harmonic magnet field and the spectra of the spontaneous emission are analyzed, and the multiple field is presented by fitting the diagram. The infiuence of the integrated field on the close orbit of the beam and on the operation parameters of the storage ring, and the compensation in the experiment are also discussed.展开更多
The atomization dynamic characteristics of a simplex swirl injector was investigated experimentally by using a hydrodynamic mechanical pulsator and the shadow photography technique. The frequency response characterist...The atomization dynamic characteristics of a simplex swirl injector was investigated experimentally by using a hydrodynamic mechanical pulsator and the shadow photography technique. The frequency response characteristics of the fluid film and atomization fluctuations and their correlations with pressure fluctuations were obtained by using an in-house code of image processing. It is demonstrated that the klystron effect induced by periodic pressure fluctuations results in periodic liquid film fluctuation with large amplitudes, periodic superposition of droplets and reduction of the breakup length. It was found that the atomization of the simplex swirl injector only responds to the pressure fluctuation in frequency range approximately from 0 to 300 Hz, and it is particularly sensitive to pressure fluctuations at frequencies from 100 to 200 Hz. According to this experiment, the responsive frequency limitation is merely affected by injector configuration, rather than the supply line.展开更多
An experimental study on the Klystron effect of periodic injection modulated by pressure drop fluctuations on subsequent atomization is conducted. Time-resolved atomization backlit images and atomization Mie scatter i...An experimental study on the Klystron effect of periodic injection modulated by pressure drop fluctuations on subsequent atomization is conducted. Time-resolved atomization backlit images and atomization Mie scatter images are captured by using the high speed camera. It is found that periodicity of forced atomization relies on pressure drop fluctuation amplitude and phase differences between atomization and pressure drop fluctuations relate to fluctuation frequencies. This feature of periodic atomization induced by Klystron effect corresponds to periodicities and high amplitudes of pressure fluctuations in unstable combustion chambers and chaos and low amplitudes of pressure fluctuations in stable combustions chambers. Drastically periodic varying of gross surface area of droplets with time was shown in Mie scatter images. The importance of periodic impinging jet atomization modulated by pressure drop fluctuations for acoustic liquid propellant combustion instabilities is illustrated.展开更多
文摘This paper details the development and testing of the first working prototype of the S-band high-power klystron,accomplished at the Budker Institute of Nuclear Physics,Siberian Branch,Russian Academy of Sciences(BINP SB RAS).Upon testing,the klystron demonstrated the following parameters:an operating frequency of 2856 MHz and a peak power output of 50 MW.The paper presents the klystron's design,its constituent units,and pertinent processing procedures,along with discussions on the measurement of its parameters.
基金Project supported by Yifang Wang’s Science Studio of the Ten Thousand Talents Project,China
文摘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 d B. 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.
基金Project supported by Yifang Wang’s Science Studio of the Ten Thousand Talents Project。
文摘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-k W 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 k V and current of 15.4 A, the klystron peak power reached 804 k W with output efficiency of about 65.3% at 40% duty cycle. The 1-d B 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.
文摘This letter reports the development of a 50MW S-band klystron in the Institute of Electronics, Chinese Academy of Sciences （IECAS）. It adopted a structure of six-cavity and single output window. Under conditions of an RF （Radio Frequency） pulse width of 4t, ts, a beam voltage of 305,9kV and a beam current of 368A, the peak output power has achieved 51.4MW with an efficiency of 45.6% and a gain of 54dB.
文摘Two methods for improving the equidriving power-frequency characteristics of broad-band high power klystrons are presented. One is that a comb-line bandpass filter with someattenuation properties is inserted between the TWT driver and the klystron for compensatingthe gain-frequency characteristics of the klystron to get the required equidriving power-frequencycharacteristics. The other is that a reactive element is connected with the input cavity to changeits resonance frequencies f<sub>0</sub> and Q<sub>L</sub>, and thus to improve the power-frequency characteristics ofthe klystron.
基金The project supported by the Meg-Science Engineering Project of Chinese Academy of Sciences
文摘The paper introduces the -35 kV/200 kW high voltage power supply (HVPS) which is specially used to test klystron units in LHCD system. The new klystrons must be tested under high voltage level before operation and the old klystrons which have worked for a longtime must be exercised by HVPS in lower hybrid current drive (LHCD) system. As the former HVPS has some shortages in engineering design and operation design, the HVPS has to be modified and rebuilt by adopting new method and technology to solve existing bottle-neck problems.
文摘The paper mainly presents the design of beam-wave interaction of a C-band high-peakpower high-efficiency broadband klystron.The beam-wave interaction section is designed based on considerations of efficiency and bandwidth synthetically.As a part of beam-wave interaction section,buncher section is simulated by Particle-In-Cell(PIC) code to observe the bunching process of electron beam to achieve high conversion efficiency of electron beam and RF field.When it comes to the other part,output circuit is designed as a three-section filter by an output cavity loaded with Chebyshev filter,and the cold test results are given.The beam-wave interaction is simulated by EGUN code and Arsenal-MSU code respectively.The simulated results indicated that,the existence of power dips in the operating bandwidth is verified by Arsenal-MSU code,comparing proper results by EGUN code.Then,the method that design parameters are not adjusted except parameters of buncher cavities to remove potential power dips is described.What is more,the simulated results of electron optics system are given by EGUN code and Arsenal-MSU code respectively.The further hot test results of klystron prove that the whole design of beam-wave interaction is effective.
文摘This paper describes a high security data transmission system over X-band microwave frequency. The paper has two parts. The first part deals with encryption of binary data by Advanced Encryption Standard (AES) using VHDL modeling of Field Programmable Gate Array (FPGA). The second part deals with a novel idea of transmitting the encrypted data by using a single klystron. This requires the simultaneous generation of a pair of two independent RF frequencies from a reflex klystron working for X-band frequency range. In this scheme, the klystron is suitably biased on the repeller terminal and superimposed on a train of AES encrypted binary data so as to create two RF frequencies one corresponding to negative peaks and the other one to the positive peaks of the data resulting in an Frequency Shift Keying (FSK) signal. The results have been verified experimentally.
文摘This letter introduces the design ideas, simulation and test results of an S-band klystron with bandwidth of 11%, which was developed by the Institute of Electronics, Chinese Academy of Sciences (IECAS). On the peak power level of 800 kW, the efficiency of klystron is more than 30%; the gain is more than 41 dB; the equal-driving relative instantaneous bandwidth is over 11%; the average power is larger than 8 kW, and the power fluctuation within bandwidth is less than 1.5 dB.
文摘Recent research progresses in Multi-Beam Klystron (MBK) in IECAS are briefly introduced in the letter. The S-band MBKs of IECAS have peak power of 120-250 kW, average power of 4-9 kW, efficiency of 35-45%, gain of 41-46 dB, beam voltage of 15-19 kV, and weight of 40-45 kg. Some key technical problems of MBK are also described and discussed. Among them,improving the design of MBK to obtain the required bandwidth, raising beam transmission to increase average power, eliminating oscillation and spray spectrum, overcoming window breakdown caused by magic mode, reducing breakdown times of electrongun, are most important things for the practical MBK. Besides, further research work in MBK in IECAS is commented.
文摘To carry out lower hybrid wave heating and current drive plasma experiment on tokamak, we need mega-watt order of microwave power generated by the parallel-running klystrons. Those klystrons must be driven by the microwave exciter. Now our microwave exciter is used for many years and its performance is decreased very much. It can not satisfy any more the hybrid wave heating and current drive plasma experiment. So we set out to design a new microwave exciter that is consist of the microwave solid components, amplitudestabilization control, modularization design with multitude-outputs, microwave phase control in order to satisfy the demand of the different work in the hybrid wave heating and current drive plasma experiment.
文摘The measured fields of the optical klystron in NSRL (National Sy-chrotron Radiation Laboratory) are given, including the distribution on the axis, and the integrated field distribution. The harmonic magnet field and the spectra of the spontaneous emission are analyzed, and the multiple field is presented by fitting the diagram. The infiuence of the integrated field on the close orbit of the beam and on the operation parameters of the storage ring, and the compensation in the experiment are also discussed.
基金supported by the National Natural Science Foundation of China(Nos.11502186 and 51606138)the National Key Basic Research Program of China(973 Program)and National Key Scientific Instrumentthe Equipment Development Projects of China(No.2012YQ04016408)
文摘The atomization dynamic characteristics of a simplex swirl injector was investigated experimentally by using a hydrodynamic mechanical pulsator and the shadow photography technique. The frequency response characteristics of the fluid film and atomization fluctuations and their correlations with pressure fluctuations were obtained by using an in-house code of image processing. It is demonstrated that the klystron effect induced by periodic pressure fluctuations results in periodic liquid film fluctuation with large amplitudes, periodic superposition of droplets and reduction of the breakup length. It was found that the atomization of the simplex swirl injector only responds to the pressure fluctuation in frequency range approximately from 0 to 300 Hz, and it is particularly sensitive to pressure fluctuations at frequencies from 100 to 200 Hz. According to this experiment, the responsive frequency limitation is merely affected by injector configuration, rather than the supply line.
基金supported by the National Natural Science Foundation of China (Nos. 11502186 and 51606138)the National Key Basic Research Program of ChinaNational Key Scientific Instrument and the Equipment Development Projects of China (No. 2012YQ04016408)
文摘An experimental study on the Klystron effect of periodic injection modulated by pressure drop fluctuations on subsequent atomization is conducted. Time-resolved atomization backlit images and atomization Mie scatter images are captured by using the high speed camera. It is found that periodicity of forced atomization relies on pressure drop fluctuation amplitude and phase differences between atomization and pressure drop fluctuations relate to fluctuation frequencies. This feature of periodic atomization induced by Klystron effect corresponds to periodicities and high amplitudes of pressure fluctuations in unstable combustion chambers and chaos and low amplitudes of pressure fluctuations in stable combustions chambers. Drastically periodic varying of gross surface area of droplets with time was shown in Mie scatter images. The importance of periodic impinging jet atomization modulated by pressure drop fluctuations for acoustic liquid propellant combustion instabilities is illustrated.
