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RSS2003 Vol. 15, No. 04
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2003,
15.
Abstract:
An online beam spot diagnostic system for high current,short pulse electron beam based on Cerenkov radiation is introduced. A 0.5mmthick, 80mmdia. quartz foil, which is placed on the actuator, is chosen as the radiator. The Cerenkov radiation signals are detected by CCD camera and the images are processed by computer. Results of beam spot measurement on the 2MeV injector and 12MeV LIA of CAEP are reported.
An online beam spot diagnostic system for high current,short pulse electron beam based on Cerenkov radiation is introduced. A 0.5mmthick, 80mmdia. quartz foil, which is placed on the actuator, is chosen as the radiator. The Cerenkov radiation signals are detected by CCD camera and the images are processed by computer. Results of beam spot measurement on the 2MeV injector and 12MeV LIA of CAEP are reported.
2003,
15.
Abstract:
The purpose of this paper is to estimate the longitudinal coupling impedance of the coated ceramic vacuum chamber employed in new injection system of Hefei Light Source. For the regular axially symmetric boundary, the analytical results of the impedance for the coated ceramic chamber can be easily obtained by application field matching techniques to Maxwell equations in cylindrical coordinate system. For the irregular boundary used in HLS, it is very hard to obtain analytical result of impedance. Based on the impedance measurement principle of coaxial wire method, the impedance of ceramic chamber was numerically calculated. The calculated results showed that, although coating inside ceramic chamber can reduce impedance by some factor, the coated ceramic chamber is one of the main impedance
The purpose of this paper is to estimate the longitudinal coupling impedance of the coated ceramic vacuum chamber employed in new injection system of Hefei Light Source. For the regular axially symmetric boundary, the analytical results of the impedance for the coated ceramic chamber can be easily obtained by application field matching techniques to Maxwell equations in cylindrical coordinate system. For the irregular boundary used in HLS, it is very hard to obtain analytical result of impedance. Based on the impedance measurement principle of coaxial wire method, the impedance of ceramic chamber was numerically calculated. The calculated results showed that, although coating inside ceramic chamber can reduce impedance by some factor, the coated ceramic chamber is one of the main impedance
2003,
15.
Abstract:
The model of helical generators whose explosive is initiated axially (MFCG) with a high inductance load has been set up in this paper. Based on the model of the MFCG that consists of 1D model for explosion driven central tube (armature), a model for magnetic field distribution inside the helix, a model for magnetic force outside the center tube and the circuit model, a code (CEMG 1.0) was compiled. Calculation results show that, the output current and pulse duration of MFCG can be enlarged as the distance between the central tube and the stator helix increases. The generator with smaller pitch of feed coil can output higher current on the load, and the generators with an aluminum tube can output shorter pulse duration than those with a copper tube. A generator with 120mm in stator coil d
The model of helical generators whose explosive is initiated axially (MFCG) with a high inductance load has been set up in this paper. Based on the model of the MFCG that consists of 1D model for explosion driven central tube (armature), a model for magnetic field distribution inside the helix, a model for magnetic force outside the center tube and the circuit model, a code (CEMG 1.0) was compiled. Calculation results show that, the output current and pulse duration of MFCG can be enlarged as the distance between the central tube and the stator helix increases. The generator with smaller pitch of feed coil can output higher current on the load, and the generators with an aluminum tube can output shorter pulse duration than those with a copper tube. A generator with 120mm in stator coil d
2003,
15.
Abstract:
With a axially-blown field distortion gas spark gap switch, a serial of experiments were performed at voltage up to 100kV, peak current up to 85kA, charge transfer up to about 0.6C per pulse, repetition rate up to 10Hz, and single shot energy up to 5kJ. The experimental results indicated that gas flow speed, electrode erosion and insulator envelope poll
With a axially-blown field distortion gas spark gap switch, a serial of experiments were performed at voltage up to 100kV, peak current up to 85kA, charge transfer up to about 0.6C per pulse, repetition rate up to 10Hz, and single shot energy up to 5kJ. The experimental results indicated that gas flow speed, electrode erosion and insulator envelope poll
2003,
15.
Abstract:
A transparent yttriastabilized zirconia (YSZ) single crystal becomes purple after 200keV Xe+irradiation. Calculation of TRIM 96 shows that 200keV Xe+ ions cause peak displacement levels of ~350dpa (displacement per atom) at the depth of 30nm in a YSZ single crystal at a dose of 1×1017cm-2, and crosssectional TEM images and diffraction pattern show that there is no amorphization. Optical absorption measurements show that a broad absorption band appears at a dose of 1×1016cm-2. For the 1×1016cm-2 and 1×1017cm-2 Xe+irradiated crystals, the absorption bands are centered at 522nm and 497nm, respectively. The bands are assigned to electrons trapped at oxygen vacancies nearest to Zr cations (Ftype centers) and to oxygen ions with trap holes adjacent to yttria cations (Vtype center
A transparent yttriastabilized zirconia (YSZ) single crystal becomes purple after 200keV Xe+irradiation. Calculation of TRIM 96 shows that 200keV Xe+ ions cause peak displacement levels of ~350dpa (displacement per atom) at the depth of 30nm in a YSZ single crystal at a dose of 1×1017cm-2, and crosssectional TEM images and diffraction pattern show that there is no amorphization. Optical absorption measurements show that a broad absorption band appears at a dose of 1×1016cm-2. For the 1×1016cm-2 and 1×1017cm-2 Xe+irradiated crystals, the absorption bands are centered at 522nm and 497nm, respectively. The bands are assigned to electrons trapped at oxygen vacancies nearest to Zr cations (Ftype centers) and to oxygen ions with trap holes adjacent to yttria cations (Vtype center
2003,
15.
Abstract:
An air core spiral strip transformer with 0.8 of coupling coefficient, which can operate in pulse high voltage, has been researched and manufactured .The experiments showed that output voltage of transformer rose up to about 500kV at an input 40kV. The elementary theoretical analysis of the transformer has been carried out . This kind of transformer has characteristic of compact construction, small volume and excellent electric performance. It has been used to charge of water Blumlein line of accelerator. In the vacuum diode of accelerator, high voltage pulse of 500kV, 40kA with 80ns (FWHM) has been obtained.
An air core spiral strip transformer with 0.8 of coupling coefficient, which can operate in pulse high voltage, has been researched and manufactured .The experiments showed that output voltage of transformer rose up to about 500kV at an input 40kV. The elementary theoretical analysis of the transformer has been carried out . This kind of transformer has characteristic of compact construction, small volume and excellent electric performance. It has been used to charge of water Blumlein line of accelerator. In the vacuum diode of accelerator, high voltage pulse of 500kV, 40kA with 80ns (FWHM) has been obtained.
2003,
15.
Abstract:
A code is written to simulate BBU in induction linac according to theoretic analysis. The general form of evolution of BBU in induction linac is investigated at first, then the effect of related parameters on BBU is analyzed, for example, the alignment error, oscillation frequency of beam centroid, beam pulse shape and acceleration gradient. At last measures are put forward to damp beam breakup unstability.
A code is written to simulate BBU in induction linac according to theoretic analysis. The general form of evolution of BBU in induction linac is investigated at first, then the effect of related parameters on BBU is analyzed, for example, the alignment error, oscillation frequency of beam centroid, beam pulse shape and acceleration gradient. At last measures are put forward to damp beam breakup unstability.
2003,
15.
Abstract:
For flash-II accelerator a new diode system was developed including a low impedance diode with a flash switch, drift tube, pulsed magnetic system and vacuum target chamber. Its electron beam fluence is three times more than that of the old diode system. By means of decreasing the diameter of cathode, increasing axial magnetic intensity and magnetic lens ratio, and adjusting the distance of flash switch and the pressure of pre-pulse switch a stable working regime of the diode with high fluence electron beam was achieved. While charging 70 kV into Marx generator electron beam of 21.5kJ total energy, spot diameter 52mm and energy fluence 1.01kJ/cm2 on target at a distance 22cm from cathode was acquired.
For flash-II accelerator a new diode system was developed including a low impedance diode with a flash switch, drift tube, pulsed magnetic system and vacuum target chamber. Its electron beam fluence is three times more than that of the old diode system. By means of decreasing the diameter of cathode, increasing axial magnetic intensity and magnetic lens ratio, and adjusting the distance of flash switch and the pressure of pre-pulse switch a stable working regime of the diode with high fluence electron beam was achieved. While charging 70 kV into Marx generator electron beam of 21.5kJ total energy, spot diameter 52mm and energy fluence 1.01kJ/cm2 on target at a distance 22cm from cathode was acquired.
2003,
15.
Abstract:
This paper expatiates on the methods marginal, horizontal and vertical shimming magnet block of OK radiator in Hefi storage ring. By means of shimming,the filed integral and phase error can be reduced as much as possible. All the measurement results of magnetic field of optical klystron before and after shimming are given, including the distribution of field integral and phase error on axis, field integral and RMS phase error for different gaps and transverse distribution of field integral. The results reveal that the radiator can meet the requirement of coherent harmonic generation FEL experimental. The same method will be used in the shimming and measurement of modulator and dispersion section of optical klystron．
This paper expatiates on the methods marginal, horizontal and vertical shimming magnet block of OK radiator in Hefi storage ring. By means of shimming,the filed integral and phase error can be reduced as much as possible. All the measurement results of magnetic field of optical klystron before and after shimming are given, including the distribution of field integral and phase error on axis, field integral and RMS phase error for different gaps and transverse distribution of field integral. The results reveal that the radiator can meet the requirement of coherent harmonic generation FEL experimental. The same method will be used in the shimming and measurement of modulator and dispersion section of optical klystron．
2003,
15.
Abstract:
A high voltage system of superposed pulse and its measurement device are described. The pulse power system is specially equipped with a high voltage transformer that has two secondary coils. Because of the unique transformer, the system can provide multiple pulses and then superpose them to be trapeziumshaped pulse, which is composed of three damped sine waveforms. Meanwhile, a structural capacity divider designed on the high voltage transformer is also presented.
A high voltage system of superposed pulse and its measurement device are described. The pulse power system is specially equipped with a high voltage transformer that has two secondary coils. Because of the unique transformer, the system can provide multiple pulses and then superpose them to be trapeziumshaped pulse, which is composed of three damped sine waveforms. Meanwhile, a structural capacity divider designed on the high voltage transformer is also presented.
2003,
15.
Abstract:
The transmission change of ZnSe/MgF2/K9 filter induced by CW laser(1.06μm) is analyzed in this paper. At room temperature, the change of the film ' s refractive index induced by heating is measured with the detecting laser beam (0632 8μm). As a result of this change, the filter's transmission varies nonlinearly. When laser beam of different power with the spot diameter 0.75mm irradiated on the ZnSe/MgF2/K9 filter, temperature change responding to irradiation time is measured. Typical experiment results are as follows : The film temperature damage threshold is 90℃ with laser power 30W and irradiation time 2.52s, checked surface of the film is formed with irradiation time 10s.
The transmission change of ZnSe/MgF2/K9 filter induced by CW laser(1.06μm) is analyzed in this paper. At room temperature, the change of the film ' s refractive index induced by heating is measured with the detecting laser beam (0632 8μm). As a result of this change, the filter's transmission varies nonlinearly. When laser beam of different power with the spot diameter 0.75mm irradiated on the ZnSe/MgF2/K9 filter, temperature change responding to irradiation time is measured. Typical experiment results are as follows : The film temperature damage threshold is 90℃ with laser power 30W and irradiation time 2.52s, checked surface of the film is formed with irradiation time 10s.
2003,
15.
Abstract:
By rudiment introductions of PID regulator, it is indicated that setting parameters of PID regulator reasonably is key to eliminate any stirs and to realize quick, accurate and stable movement of mirrors. Through applications of PID regulator and actuator, it is improved the alignment of the reflecting mirrors in the resonator in the static state and mirrors may be real time aligned in the dynamic state to a certain degree. It is possible that the drift and deformation for COIL output beam spot is reduced.
By rudiment introductions of PID regulator, it is indicated that setting parameters of PID regulator reasonably is key to eliminate any stirs and to realize quick, accurate and stable movement of mirrors. Through applications of PID regulator and actuator, it is improved the alignment of the reflecting mirrors in the resonator in the static state and mirrors may be real time aligned in the dynamic state to a certain degree. It is possible that the drift and deformation for COIL output beam spot is reduced.
2003,
15.
Abstract:
In order to solve the optical axis deflection owing to asymmetric thermal deformation of mirror induced by irregular facula, phase change cooled mirror, which takes the place of normal silicon mirror, is presented to minimize PV value of deformation on mirror surface and mirror deflection. Online tests are carried out on 2kW CW carbon dioxide laser. The experimental results indicate that: Compared with normal silicon mirror, phase change cooled mirror achieves more uniform temperature field on surface. It can diminish angle of mirror deflection and centroid drift, and improve the beam quality in the far field.
In order to solve the optical axis deflection owing to asymmetric thermal deformation of mirror induced by irregular facula, phase change cooled mirror, which takes the place of normal silicon mirror, is presented to minimize PV value of deformation on mirror surface and mirror deflection. Online tests are carried out on 2kW CW carbon dioxide laser. The experimental results indicate that: Compared with normal silicon mirror, phase change cooled mirror achieves more uniform temperature field on surface. It can diminish angle of mirror deflection and centroid drift, and improve the beam quality in the far field.
2003,
15.
Abstract:
For the system of Cl/Cl2/HN3/He which is the basis of concept of NCl(a1Δ)/I as a newly possible laser system, the amount of the production of chlorine atoms is essential and important to the system. In this paper, the dissociation efficiency of chlorine by a Microwave Generator is investigated by a versatile titration technique. The intensity of NCl(a1Δ) and NCl(b1Σ) emission is monitored by an OMA with the titration of mixture of He and HN3. The dissociation efficiency of chlorine by Microwave Generator is not low as expected, it is up to 100% at lower flow rate of chlorine and decreases with increasing chlorine flow rates.
For the system of Cl/Cl2/HN3/He which is the basis of concept of NCl(a1Δ)/I as a newly possible laser system, the amount of the production of chlorine atoms is essential and important to the system. In this paper, the dissociation efficiency of chlorine by a Microwave Generator is investigated by a versatile titration technique. The intensity of NCl(a1Δ) and NCl(b1Σ) emission is monitored by an OMA with the titration of mixture of He and HN3. The dissociation efficiency of chlorine by Microwave Generator is not low as expected, it is up to 100% at lower flow rate of chlorine and decreases with increasing chlorine flow rates.
2003,
15.
Abstract:
Against the problem that amplitude of pre-pulse current is too high and duration is too short in the capillary discharge pumped X-ray laser device, a complete remaking scheme was brought forward. Through adding the pre-pulse switch to reduce original pre-pulse influence and applying pulse-forming network pre-pulse generator to create required pre-pulse, the set satisfies requirement of capillary discharge-pumped Ar Nelike soft X-ray laser experiments with amplitude of pre-pulse current 10~50kA, duration about 17μs.
Against the problem that amplitude of pre-pulse current is too high and duration is too short in the capillary discharge pumped X-ray laser device, a complete remaking scheme was brought forward. Through adding the pre-pulse switch to reduce original pre-pulse influence and applying pulse-forming network pre-pulse generator to create required pre-pulse, the set satisfies requirement of capillary discharge-pumped Ar Nelike soft X-ray laser experiments with amplitude of pre-pulse current 10~50kA, duration about 17μs.
2003,
15.
Abstract:
CARS spectra have been recorded and evaluated for temperature determination in CH4/air flame. Temperature on the flame axis at different height above the burner surface has been measured; It has also been measured with different gas flow rates, and the spatially resolution have been calculated with actual experimental parameter. These results indicate that temperature at the combustion field can be measured with high precision and high spatially resolution by BOXCARS.
CARS spectra have been recorded and evaluated for temperature determination in CH4/air flame. Temperature on the flame axis at different height above the burner surface has been measured; It has also been measured with different gas flow rates, and the spatially resolution have been calculated with actual experimental parameter. These results indicate that temperature at the combustion field can be measured with high precision and high spatially resolution by BOXCARS.
2003,
15.
Abstract:
In this paper , colloid-based multilayer coatings consisting of alternating layers of high-and low-refractive index compo nents were deposited on K9 glass and silicon wafer substrates by Sol-Gel spin-coating method. SiO2 was used as the low-refractive index component and ZrO2 as the high-refractive index material. The colloidal suspension of ZrO2 was prepared by hydrothermal hydrolysis of ZrOCl2 . The solvent in colloidal suspension of SiO2 was replaced by methoxyethanol through distillation. A high-pressure mercury lamp was used to do the irradiation treatment . SEM , IR and UV-VIS spectrophotometer were used to characterize the structure and optical properties of the films. Ellipssometry was used to study the thickness and refractive index of the films. The films were irradiated by a Q
In this paper , colloid-based multilayer coatings consisting of alternating layers of high-and low-refractive index compo nents were deposited on K9 glass and silicon wafer substrates by Sol-Gel spin-coating method. SiO2 was used as the low-refractive index component and ZrO2 as the high-refractive index material. The colloidal suspension of ZrO2 was prepared by hydrothermal hydrolysis of ZrOCl2 . The solvent in colloidal suspension of SiO2 was replaced by methoxyethanol through distillation. A high-pressure mercury lamp was used to do the irradiation treatment . SEM , IR and UV-VIS spectrophotometer were used to characterize the structure and optical properties of the films. Ellipssometry was used to study the thickness and refractive index of the films. The films were irradiated by a Q
2003,
15.
Abstract:
A middle to far infrared detector, which uses a YBCO high temperature superconductive thin film, is introduced in the paper. The research on its middle to far infrared response characteristics is conducted by utilizing the Beijing Free Electronic Laser. The microbridge size of the test target is 210μm×70μm×0.3μm and its voltage, spectrum, and time responses are measured. Results show that the YBCO high temperature superconductive light detector, which works under the temperature of liquid nitrogen, has properties of fast response ,high sensibility, good wide bandwidth and good stability.
A middle to far infrared detector, which uses a YBCO high temperature superconductive thin film, is introduced in the paper. The research on its middle to far infrared response characteristics is conducted by utilizing the Beijing Free Electronic Laser. The microbridge size of the test target is 210μm×70μm×0.3μm and its voltage, spectrum, and time responses are measured. Results show that the YBCO high temperature superconductive light detector, which works under the temperature of liquid nitrogen, has properties of fast response ,high sensibility, good wide bandwidth and good stability.
2003,
15.
Abstract:
This paper investigates the forming of the interference fringes which are employed in long distance interferometric imaging. The characterization of the desired fringes is analyzed. The deficiencies of employing the traditional Michelson interferometer are discussed. A new optical structure to form circular symmetric fringes was proposed and an experiment was performed for verifying the new idea. A fringe pattern has been observed at a distance of 50m with a little instability, which may be caused by the small vibration of the mechanics. The experiment shows that the new optical structure is feasible.
This paper investigates the forming of the interference fringes which are employed in long distance interferometric imaging. The characterization of the desired fringes is analyzed. The deficiencies of employing the traditional Michelson interferometer are discussed. A new optical structure to form circular symmetric fringes was proposed and an experiment was performed for verifying the new idea. A fringe pattern has been observed at a distance of 50m with a little instability, which may be caused by the small vibration of the mechanics. The experiment shows that the new optical structure is feasible.
2003,
15.
Abstract:
This paper stated applying method of high speed photography to study centripetal motion of plasma generated by gas-puff Z-pinch internal explosion on anode accelerator. The scanning images with high temporal resolution of plasma pinching generated by anode accelerator applying Neon as gas-puff load, was obtained using image-converter streak camera. The process of plasma internal explosion pinching was observed, and the curves of plasma pinching diameter corresponding to scanning time were given.
This paper stated applying method of high speed photography to study centripetal motion of plasma generated by gas-puff Z-pinch internal explosion on anode accelerator. The scanning images with high temporal resolution of plasma pinching generated by anode accelerator applying Neon as gas-puff load, was obtained using image-converter streak camera. The process of plasma internal explosion pinching was observed, and the curves of plasma pinching diameter corresponding to scanning time were given.
2003,
15.
Abstract:
This paper describes the novel power conditioning systems(PCS) with a preionization/lamp check（PILC）for flashlamppumped laser. Its architecture is different from any traditional laser power conditioning system and was chosen as the most costeffective way to reliably deliver the large amounts of electrical energy needed for laser ICF facilities. The design of the power conditioning systems represents an evolution that has occurred over many years and several generations of lasers. The direction of this evolution has been to build modules that can handle larger amounts of energy with a smaller number of components. Although the novel power conditioning design involves several technical challenges(The operation of parallel flashlamp, large module size, parallel capacitor, large capaci
This paper describes the novel power conditioning systems(PCS) with a preionization/lamp check（PILC）for flashlamppumped laser. Its architecture is different from any traditional laser power conditioning system and was chosen as the most costeffective way to reliably deliver the large amounts of electrical energy needed for laser ICF facilities. The design of the power conditioning systems represents an evolution that has occurred over many years and several generations of lasers. The direction of this evolution has been to build modules that can handle larger amounts of energy with a smaller number of components. Although the novel power conditioning design involves several technical challenges(The operation of parallel flashlamp, large module size, parallel capacitor, large capaci
2003,
15.
Abstract:
One dimension multigroup radiation transfer code (RDMG) was used to simulate the process of radiation transfer in CH foam. The results show that in the same condition of incident flux, the CH density has an remarkable effect on the character of radiation transfer, the processes of thermodynamic equilibrium relaxation of radiation heating matter. When the density is going down, the supersonic heating wave will be substituted for the ablative heating wave in the matter. The character of radiation spectrum also varies with the density in the process of the transfer. In this paper, some detail physical pictures and quantitative results are given.
One dimension multigroup radiation transfer code (RDMG) was used to simulate the process of radiation transfer in CH foam. The results show that in the same condition of incident flux, the CH density has an remarkable effect on the character of radiation transfer, the processes of thermodynamic equilibrium relaxation of radiation heating matter. When the density is going down, the supersonic heating wave will be substituted for the ablative heating wave in the matter. The character of radiation spectrum also varies with the density in the process of the transfer. In this paper, some detail physical pictures and quantitative results are given.
2003,
15.
Abstract:
Nanocopper particles were prepared by flow-levitation method. The structures, morphologies, granularities and the surface oxide layers of particles were investigated by TEM, XRD, and AES techniques. The results show that single-crystal nanocopper particles can be produced by this method, in addition, granularities of particles can be controlled by adjusting the procedure parameters.
Nanocopper particles were prepared by flow-levitation method. The structures, morphologies, granularities and the surface oxide layers of particles were investigated by TEM, XRD, and AES techniques. The results show that single-crystal nanocopper particles can be produced by this method, in addition, granularities of particles can be controlled by adjusting the procedure parameters.
2003,
15.
Abstract:
Designing an octave bandwidth helical traveling wave tube(TWT) for phase and gain matched operation in the EHF region presents many obstacles, for example the dimensional controls.Recent advance in computer modeling offer the possibility to evaluate the effect of slow-wave structure parameter and operating parameter variations, such as manufacturing tolerances, which will enable manufacturers to determine the cost effectiveness of controlling the dimensions of the component parts of the TWT. In this paper, computer code PGMTWT is programmed, which includes helical slow-wave circuit code and 2-Dimensional large-signal including harmonics interaction helical TWT interaction code. The effect on curve of gain and phase dispersion for frequency, when helical slow-wave circuit parameter and oper
Designing an octave bandwidth helical traveling wave tube(TWT) for phase and gain matched operation in the EHF region presents many obstacles, for example the dimensional controls.Recent advance in computer modeling offer the possibility to evaluate the effect of slow-wave structure parameter and operating parameter variations, such as manufacturing tolerances, which will enable manufacturers to determine the cost effectiveness of controlling the dimensions of the component parts of the TWT. In this paper, computer code PGMTWT is programmed, which includes helical slow-wave circuit code and 2-Dimensional large-signal including harmonics interaction helical TWT interaction code. The effect on curve of gain and phase dispersion for frequency, when helical slow-wave circuit parameter and oper
2003,
15.
Abstract:
There is an ununiformity with the electron beam energy spread at Beijing Free Electron Laser Facilitis. It is observed that the electron energy in front of the current pulse rose much higher than the average,that this portion of electron bunchs lost in the bending segment and could not devote its energy to laser gain.This disfigurement is considered to be caused by the difference of building time of microwave field inside the RF gun and the accelerator.One cavity with low quality factor to shorten this difference was introduced in this paper,and an upgrade design of new thermionic cathode made of this kind of cavity is expected to improve laser gain.
There is an ununiformity with the electron beam energy spread at Beijing Free Electron Laser Facilitis. It is observed that the electron energy in front of the current pulse rose much higher than the average,that this portion of electron bunchs lost in the bending segment and could not devote its energy to laser gain.This disfigurement is considered to be caused by the difference of building time of microwave field inside the RF gun and the accelerator.One cavity with low quality factor to shorten this difference was introduced in this paper,and an upgrade design of new thermionic cathode made of this kind of cavity is expected to improve laser gain.
2003,
15.
Abstract:
A new structure of high power and high frequency microwave oscillator based on the transittime instability is proposed and studied numerically in this paper. Due to its coaxial structure with large radius, the oscillator allows larger input and output power and can work at higher frequency. Without external magnetic field being used for beam focusing, it keeps the simplicity of a conventional transittime oscillator. Using an electron beam of 225kV and 11kA, a stable and monochromatic output with peak power of 1.4GW is achieved by simulation at 8.335GHz with an rms efficiency of 28%.
A new structure of high power and high frequency microwave oscillator based on the transittime instability is proposed and studied numerically in this paper. Due to its coaxial structure with large radius, the oscillator allows larger input and output power and can work at higher frequency. Without external magnetic field being used for beam focusing, it keeps the simplicity of a conventional transittime oscillator. Using an electron beam of 225kV and 11kA, a stable and monochromatic output with peak power of 1.4GW is achieved by simulation at 8.335GHz with an rms efficiency of 28%.
