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RSS2003 Vol. 15, No. 10
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2003,
15.
Abstract:
Perdeuterated polymer film is a typical target of fast ignition physics. Perdeuterated polystyrene (DPS) was synthesized by free radical polymerization, and DPS films with thickness from 30nm to 450μm were prepared by dip coating and casting. The influence of the random disturbance occurred at gaslliquid interface on the thickness distribution of the DPS films would be reduced by clean substrate and cover on the substrate or mould. The thinner films can be obtamed with PVA as stripping agent. The glass transition temperature of the DPS film is relevant to its heat history. Annealing slowly increases the T-g and storage modulus of the films.
Perdeuterated polymer film is a typical target of fast ignition physics. Perdeuterated polystyrene (DPS) was synthesized by free radical polymerization, and DPS films with thickness from 30nm to 450μm were prepared by dip coating and casting. The influence of the random disturbance occurred at gaslliquid interface on the thickness distribution of the DPS films would be reduced by clean substrate and cover on the substrate or mould. The thinner films can be obtamed with PVA as stripping agent. The glass transition temperature of the DPS film is relevant to its heat history. Annealing slowly increases the T-g and storage modulus of the films.
2003,
15.
Abstract:
Comparison between RayleighTaylor instability growth rates of compressible and incompressible fluid is made, with the state equation of compressible fluid in an arbitrary function form of density and pressure. It is shown that with the same density distribution, interface perturbation growth rate of compressible fluid is always greater than the counter one. The relative growth rate increases with perturbation wavelength, and decreases with velocity of sound of upper and lower fluid. The value of relative growth rate can exceed 0.8 at long wave and more compressible fluid, so compressibility of fluid shouldn't be neglected at some conditions.
Comparison between RayleighTaylor instability growth rates of compressible and incompressible fluid is made, with the state equation of compressible fluid in an arbitrary function form of density and pressure. It is shown that with the same density distribution, interface perturbation growth rate of compressible fluid is always greater than the counter one. The relative growth rate increases with perturbation wavelength, and decreases with velocity of sound of upper and lower fluid. The value of relative growth rate can exceed 0.8 at long wave and more compressible fluid, so compressibility of fluid shouldn't be neglected at some conditions.
2003,
15.
Abstract:
On the XingguangII laser facility, one dimensional spaceresoved Mband spectra on Au plasmas produced laser irradiation of a plane target were measured by using a PET crystal spectrometer coupled with a slit of 20μm in width. In the experimental spectra, electric quadrupole transition line 3p63d10(1S0)3p53d104d(3/2,5/2)J=1 of Nilike Au was observed, and according to the sensitive characteristic of this line to electron density, diagnostics of the electron density of Au plasmas were discussed. In conclusion, the use of electric quadrupole line as a diagnostic tool of electron density is available in the range of about 1019～ 4.5×1021cm-3.
On the XingguangII laser facility, one dimensional spaceresoved Mband spectra on Au plasmas produced laser irradiation of a plane target were measured by using a PET crystal spectrometer coupled with a slit of 20μm in width. In the experimental spectra, electric quadrupole transition line 3p63d10(1S0)3p53d104d(3/2,5/2)J=1 of Nilike Au was observed, and according to the sensitive characteristic of this line to electron density, diagnostics of the electron density of Au plasmas were discussed. In conclusion, the use of electric quadrupole line as a diagnostic tool of electron density is available in the range of about 1019～ 4.5×1021cm-3.
2003,
15.
Abstract:
In order to obtain self-consistent space charge limited electron emission model in electromagnetic PIC(particleincell) simulation of foilless diode, Child law model, Gauss law model and 1D diode model have been analyzed and compared. The simulation results show that the three models are all selfconsistent with electromagnetic field. Gauss law model tends to be affected by the width of the first cell and yield nonphysical oscillation. 1D diode model with reasonable discrete grid gets almost the same results as Child law model, but it needs to solve a transcendental equation, which would cost much time. And it is demonstrated that the external applied magnetic field has little influence on the emission model and can be neglected in the electromagnetic PIC simulations. Child law mod
In order to obtain self-consistent space charge limited electron emission model in electromagnetic PIC(particleincell) simulation of foilless diode, Child law model, Gauss law model and 1D diode model have been analyzed and compared. The simulation results show that the three models are all selfconsistent with electromagnetic field. Gauss law model tends to be affected by the width of the first cell and yield nonphysical oscillation. 1D diode model with reasonable discrete grid gets almost the same results as Child law model, but it needs to solve a transcendental equation, which would cost much time. And it is demonstrated that the external applied magnetic field has little influence on the emission model and can be neglected in the electromagnetic PIC simulations. Child law mod
2003,
15.
Abstract:
In order to investigate the highfrequency characteristics of the Xband fiveunit transittime tube oscillator (TTTO), the method of finiteunit differential of time domain (FDTD) is involved, then the Maxwell Equations are solved. And the frequency of the eigenmodes (belonging to nonpi mode of TM01 mode) and its distribution of electric field together with the Qvalue in the cavity are presented. Additionally, the experimental results are also put out. The experimental results are in accordance with the results of the numerical solution, which proves the reliability of the results.
In order to investigate the highfrequency characteristics of the Xband fiveunit transittime tube oscillator (TTTO), the method of finiteunit differential of time domain (FDTD) is involved, then the Maxwell Equations are solved. And the frequency of the eigenmodes (belonging to nonpi mode of TM01 mode) and its distribution of electric field together with the Qvalue in the cavity are presented. Additionally, the experimental results are also put out. The experimental results are in accordance with the results of the numerical solution, which proves the reliability of the results.
2003,
15.
Abstract:
In terms of the equations describing motion of the electron and evolution of the radiation field, the instabilities existed in the interaction process of electrons and the field are analyzed. The results show that the development of the instability leads to the limit cycle oscillation and chaotic behavior of the radiation field. In the soft nonlinear regime, the radiation field is characterized by intermittent limit cycle oscillation; In the hard nonlinear regime, the radiation field is characterized by continuous chaotic behavior. The appearing of the unsteady states may be accelerated and repressed by the detuning. Higher output power can be obtained by optimizing the parameters.
In terms of the equations describing motion of the electron and evolution of the radiation field, the instabilities existed in the interaction process of electrons and the field are analyzed. The results show that the development of the instability leads to the limit cycle oscillation and chaotic behavior of the radiation field. In the soft nonlinear regime, the radiation field is characterized by intermittent limit cycle oscillation; In the hard nonlinear regime, the radiation field is characterized by continuous chaotic behavior. The appearing of the unsteady states may be accelerated and repressed by the detuning. Higher output power can be obtained by optimizing the parameters.
2003,
15.
Abstract:
The multipole theory (MT) method is presented as a new approach for the analysis and design of various shielded multiconductor cables. The solution of boundary-value problem associated with the shielded multiconductor cable is represented by the generalized MT formula, and the procedure to obtain the capacitance of shielded multiconductor cable is described. Three representative computational examples, the deformed coaxial cable, the shielded balanced-pair transmission line and the cable consisting of 10 cylindrical conductors, are given to validate the theory, and to demonstrate the accuracy and flexibility of the MT method.
The multipole theory (MT) method is presented as a new approach for the analysis and design of various shielded multiconductor cables. The solution of boundary-value problem associated with the shielded multiconductor cable is represented by the generalized MT formula, and the procedure to obtain the capacitance of shielded multiconductor cable is described. Three representative computational examples, the deformed coaxial cable, the shielded balanced-pair transmission line and the cable consisting of 10 cylindrical conductors, are given to validate the theory, and to demonstrate the accuracy and flexibility of the MT method.
2003,
15.
Abstract:
Traditional transit-time oscillators such as split-cavity oscillator, three-cavity oscillator (TCO), super-reltron etc., have a common characteristic that the span between foils in the modulating cavity is equal. By varying span from equal to different, we developed a new device called nonuniform three cavity oscillator (NTCO). Based on the motion of the single electron whose incident phase is φ0 in standing wave electric field under the small signal condition, the transit-time effect of electron beam in π mode standing wave electric field in the NTCO is investigated, function expression of beam-wave power conversion efficiency is obtained, constrained optimization problems are solved through “penalty function method”, the conclusion is obtained that beam-wave power conversion efficien
Traditional transit-time oscillators such as split-cavity oscillator, three-cavity oscillator (TCO), super-reltron etc., have a common characteristic that the span between foils in the modulating cavity is equal. By varying span from equal to different, we developed a new device called nonuniform three cavity oscillator (NTCO). Based on the motion of the single electron whose incident phase is φ0 in standing wave electric field under the small signal condition, the transit-time effect of electron beam in π mode standing wave electric field in the NTCO is investigated, function expression of beam-wave power conversion efficiency is obtained, constrained optimization problems are solved through “penalty function method”, the conclusion is obtained that beam-wave power conversion efficien
2003,
15.
Abstract:
The vaneloaded helical slowwave structures is widely used in high power, broadband travelingwave tubes (TWT's). Taking the radial thickness of the helix into account, the tape helix model is suggested for the vaneloaded helical slowwave structures in this paper for the first time. By taking the discrete supports bars into some continuous dielectric tube regions, the dispersion equations and the expressions of interaction impedance are obtained. Besides, the radial propagation constant of every layer in the dielectricloaded region is differentiated. Some helical slowwave structures of TWT are calculated by the derived equations, and the calculated results accord with measured values very well. Compared with measured values, the calculated results of the model considering the r
The vaneloaded helical slowwave structures is widely used in high power, broadband travelingwave tubes (TWT's). Taking the radial thickness of the helix into account, the tape helix model is suggested for the vaneloaded helical slowwave structures in this paper for the first time. By taking the discrete supports bars into some continuous dielectric tube regions, the dispersion equations and the expressions of interaction impedance are obtained. Besides, the radial propagation constant of every layer in the dielectricloaded region is differentiated. Some helical slowwave structures of TWT are calculated by the derived equations, and the calculated results accord with measured values very well. Compared with measured values, the calculated results of the model considering the r
2003,
15.
Abstract:
In the inertial confinement fusion (ICF), to achieve optimum fuel compression, the laser beams must irradiate the target uniformly, which require excellent beam quality. The effect of stimulated rotational Raman scattering (SRRS) leads to losses of beam quality. In this paper, using the modeling of transient stimulated rotational Raman scattering and considering many factors including the pulsedshape of laser beams, the nonlinear polarization of the medium, the depletion of pump laser, the nonlinear amplifier of the Stokes field, and the Raman bandwidth, etc. the SRRS of highpower ultraviolet laser beams in long air path is studied. The conversion efficiency of SRRS and the threshold condition for the SRRS effect is also discussed. The effect of SRRS on laser beam quality is analyzed i
In the inertial confinement fusion (ICF), to achieve optimum fuel compression, the laser beams must irradiate the target uniformly, which require excellent beam quality. The effect of stimulated rotational Raman scattering (SRRS) leads to losses of beam quality. In this paper, using the modeling of transient stimulated rotational Raman scattering and considering many factors including the pulsedshape of laser beams, the nonlinear polarization of the medium, the depletion of pump laser, the nonlinear amplifier of the Stokes field, and the Raman bandwidth, etc. the SRRS of highpower ultraviolet laser beams in long air path is studied. The conversion efficiency of SRRS and the threshold condition for the SRRS effect is also discussed. The effect of SRRS on laser beam quality is analyzed i
2003,
15.
Abstract:
Based on the FresnelKirchhoff diffraction theory, this paper calculated the intensity distribution of the farfield diffraction patterns when a divergent or a convergent gaussian beam transmitted through a thin nonlinear medium, and analyzed the effect of the different Kerr mediums and the different gaussian beams on the patterns formation. The simulation results show that, when a divergent gaussian beam transmits through a defocusing nonlinear medium or a convergent one through a focusing nonlinear medium the pattern in the far field is a series of thick, larger diffraction rings with a central dark spot, while when a divergent gaussian beam transmits through a focusing nonlinear medium or a convergent one through a defocusing nonlinear medium the pattern in the far field is a series o
Based on the FresnelKirchhoff diffraction theory, this paper calculated the intensity distribution of the farfield diffraction patterns when a divergent or a convergent gaussian beam transmitted through a thin nonlinear medium, and analyzed the effect of the different Kerr mediums and the different gaussian beams on the patterns formation. The simulation results show that, when a divergent gaussian beam transmits through a defocusing nonlinear medium or a convergent one through a focusing nonlinear medium the pattern in the far field is a series of thick, larger diffraction rings with a central dark spot, while when a divergent gaussian beam transmits through a focusing nonlinear medium or a convergent one through a defocusing nonlinear medium the pattern in the far field is a series o
2003,
15.
Abstract:
The slant visibility is an important parameter in space survey application, meteorology, remote sensing, and so on. It is wellknown the horizontal visibility has a definite relation with the atmospheric extinction coefficient, which is considered as the fundamental of meterorology,but for the slant visibility, the case is entirely different. Besides related to the atmospheric extinction coefficient, the slant visibility is evaluated to be influenced by many factors, such as the visual direction, the solar zenith angle, etc. Due to the complicated process of solving the radiative transfer equation, so far, few literatures could be obtained that described the clear numerical relations between the slant visibility and those effective factors. In this paper, based on the radiative transfer t
The slant visibility is an important parameter in space survey application, meteorology, remote sensing, and so on. It is wellknown the horizontal visibility has a definite relation with the atmospheric extinction coefficient, which is considered as the fundamental of meterorology,but for the slant visibility, the case is entirely different. Besides related to the atmospheric extinction coefficient, the slant visibility is evaluated to be influenced by many factors, such as the visual direction, the solar zenith angle, etc. Due to the complicated process of solving the radiative transfer equation, so far, few literatures could be obtained that described the clear numerical relations between the slant visibility and those effective factors. In this paper, based on the radiative transfer t
2003,
15.
Abstract:
Till now the aspherical lens used for high power density laser in China were all made manually. The quality of the lens depended closely on the skill of the craftsman, but CCOS (computer controlled Optical Surfacing) technology does not have this fault. In China, research on CCOS were focused on reflected aspherical mirror and planar mirror, but not on aspherical lens. In this paper, the technology of CCOS fabrication aspherical lens is presented. This technology include analyzing the lens parameter, the style of the machine control, fabrication moving style, parameters used in the experiment, optical testing style, and the experiment achieves the desired results.
Till now the aspherical lens used for high power density laser in China were all made manually. The quality of the lens depended closely on the skill of the craftsman, but CCOS (computer controlled Optical Surfacing) technology does not have this fault. In China, research on CCOS were focused on reflected aspherical mirror and planar mirror, but not on aspherical lens. In this paper, the technology of CCOS fabrication aspherical lens is presented. This technology include analyzing the lens parameter, the style of the machine control, fabrication moving style, parameters used in the experiment, optical testing style, and the experiment achieves the desired results.
2003,
15.
Abstract:
On the basis of research on focusing characteristics of higherorder modes Gaussian beam in flying optics, the adaptive focusing system, which can deal with the focusing characteristics of flying optics, is introduced. The numerical simulation results of adjusting characteristics of the adaptive system indicate that the control of focus position and focus radius can be achieved during long distance laser processing for flying optics.
On the basis of research on focusing characteristics of higherorder modes Gaussian beam in flying optics, the adaptive focusing system, which can deal with the focusing characteristics of flying optics, is introduced. The numerical simulation results of adjusting characteristics of the adaptive system indicate that the control of focus position and focus radius can be achieved during long distance laser processing for flying optics.
2003,
15.
Abstract:
Combined with series expansion method (SEM), threedimensional scalar beam propagation method (BPM) is transformed into the firstorder normal differential equations. And the function of tangent is applied to map the infinite space into a finite space to avoid boundary truncation. Compared with the traditional BPM, this method has the advantages of simple calculation, high calculation efficiency and small deduced matrix. The lithium niobate electrooptic waveguide modulator with MachZehnder structure is simulated by this method. The authors get its optical field distribution and acquire its optimal structure and its power loss curve.
Combined with series expansion method (SEM), threedimensional scalar beam propagation method (BPM) is transformed into the firstorder normal differential equations. And the function of tangent is applied to map the infinite space into a finite space to avoid boundary truncation. Compared with the traditional BPM, this method has the advantages of simple calculation, high calculation efficiency and small deduced matrix. The lithium niobate electrooptic waveguide modulator with MachZehnder structure is simulated by this method. The authors get its optical field distribution and acquire its optimal structure and its power loss curve.
2003,
15.
Abstract:
A high power diode-pumped Q-switched intracavity-doubled Nd:YAG laser has been developed successfully.A Q-switched laser output of 32.5W with 350W pumping power is obtained at 7kHz using a 30% output coupler.A green output of 32.5W is achieved with pulse duration of about 120ns using a type II KTP crystal.The output beam exhibits a smooth Gaussian-like profile in the far field and the beam quality factor is measured to be 3.6.
A high power diode-pumped Q-switched intracavity-doubled Nd:YAG laser has been developed successfully.A Q-switched laser output of 32.5W with 350W pumping power is obtained at 7kHz using a 30% output coupler.A green output of 32.5W is achieved with pulse duration of about 120ns using a type II KTP crystal.The output beam exhibits a smooth Gaussian-like profile in the far field and the beam quality factor is measured to be 3.6.
2003,
15.
Abstract:
In this paper the construction and the operating principle of the fast piezo steering mirror are introduced, and the differential equation of the tilting motion is established according to the Lagrange's equation, the formula of the natural frequency is derived. The model analysis of the fast steering mirror is also carried out with the help of limited element analysis. The theoretic result fits with the result of experiment. The model results can be provided for the construction design of the fast steering mirror.
In this paper the construction and the operating principle of the fast piezo steering mirror are introduced, and the differential equation of the tilting motion is established according to the Lagrange's equation, the formula of the natural frequency is derived. The model analysis of the fast steering mirror is also carried out with the help of limited element analysis. The theoretic result fits with the result of experiment. The model results can be provided for the construction design of the fast steering mirror.
2003,
15.
Abstract:
This paper presents a method of obtaining distorted wavefront and farfield spots generated by ideal beams from a mirror of laser induced deformations, through the calculating the interferograms of mirrors which are obtained by the experimental method of equivalent power density of pure absorption, and discusses a new idea of measuring farfield spot of high power laser. The results of quantitative analysis indicate that, for pure Si mirror, when the power of pure absorption is 210W and irradiating time is 6s, the maximum thermal deformation is 760nm，and because of deformations the defocusing of nearfield wavefront 320nm， primary coma along x axis and y axis is 130nm and 220nm respectively, the tilt along x axis is up to 120nm, and the beam quality factor is 5.7.
This paper presents a method of obtaining distorted wavefront and farfield spots generated by ideal beams from a mirror of laser induced deformations, through the calculating the interferograms of mirrors which are obtained by the experimental method of equivalent power density of pure absorption, and discusses a new idea of measuring farfield spot of high power laser. The results of quantitative analysis indicate that, for pure Si mirror, when the power of pure absorption is 210W and irradiating time is 6s, the maximum thermal deformation is 760nm，and because of deformations the defocusing of nearfield wavefront 320nm， primary coma along x axis and y axis is 130nm and 220nm respectively, the tilt along x axis is up to 120nm, and the beam quality factor is 5.7.
2003,
15.
Abstract:
Distribution of electromagnetic field in the space of Htype RF ion source is researched theoretically. Threedimensional vector graphs of electric field intensity and magnetic induction density in the space of RF ion source are calculated and plotted by Mafia software. The conclusion that axial electric field intensity is more important during the breakdown of RF ion source is made out by comparing it and azimuthal electric field intensity before breakdown, and then, the breakdown criterion of RF ion source is calculated, which is reasonably in agreement with experimental data.
Distribution of electromagnetic field in the space of Htype RF ion source is researched theoretically. Threedimensional vector graphs of electric field intensity and magnetic induction density in the space of RF ion source are calculated and plotted by Mafia software. The conclusion that axial electric field intensity is more important during the breakdown of RF ion source is made out by comparing it and azimuthal electric field intensity before breakdown, and then, the breakdown criterion of RF ion source is calculated, which is reasonably in agreement with experimental data.
2003,
15.
Abstract:
In this paper the old longitudinal coupling impedance measurement system of National Synchrotron Radiation Laboratory is reviewed briefly. Considering the deficiency of the old system and advance of measurement apparatus, the improvements of measurement principle and hardwares were made. The measurement principle, system hardware configuration of new improved measurement system based on coaxialwire method is presented in details. The measured impedance is agreement well with the calculated impedance by ABCI code, and the performance of the new system was demonstrated.
In this paper the old longitudinal coupling impedance measurement system of National Synchrotron Radiation Laboratory is reviewed briefly. Considering the deficiency of the old system and advance of measurement apparatus, the improvements of measurement principle and hardwares were made. The measurement principle, system hardware configuration of new improved measurement system based on coaxialwire method is presented in details. The measured impedance is agreement well with the calculated impedance by ABCI code, and the performance of the new system was demonstrated.
2003,
15.
Abstract:
A doublepulse line induced accelerator (LIA) module is reconstructed based on a usual singlepulse LIA module. By changing the length of one of the cables between the inductive cell and the Blumlein pulse forming line, two induction pulses are generated by the ferrite cores inductive cell. The interval time of the pulses is adjustable by changing the lengths of the cable, also the input voltage is changed in different experiments. The results show that it is possible for the existing LIA power system to generate multipulses; the ferrite cores of LIA can induct multipulses when their voltagesecond range is enough; and the resetting effect of the cores is tied up with the resetting time and resetting voltage.
A doublepulse line induced accelerator (LIA) module is reconstructed based on a usual singlepulse LIA module. By changing the length of one of the cables between the inductive cell and the Blumlein pulse forming line, two induction pulses are generated by the ferrite cores inductive cell. The interval time of the pulses is adjustable by changing the lengths of the cable, also the input voltage is changed in different experiments. The results show that it is possible for the existing LIA power system to generate multipulses; the ferrite cores of LIA can induct multipulses when their voltagesecond range is enough; and the resetting effect of the cores is tied up with the resetting time and resetting voltage.
2003,
15.
Abstract:
A 10kV solidstate switch for high pulse power application has been developed. The prototype makes use of switches made of arranged in series. The output voltage can be adjusted from 1 to 10kV and the pulse width can be varied from 2 to 110 microseconds, the pulsing frequency in the initial design can be changed from 1Hz to 4kHz. Experimental results show that the solidstate switch can operate in the frequency up to 8.6kHz and in the voltage up to 14kV. The typical rise time is less than 300ns and the typical fall time is about 1.25μs.
A 10kV solidstate switch for high pulse power application has been developed. The prototype makes use of switches made of arranged in series. The output voltage can be adjusted from 1 to 10kV and the pulse width can be varied from 2 to 110 microseconds, the pulsing frequency in the initial design can be changed from 1Hz to 4kHz. Experimental results show that the solidstate switch can operate in the frequency up to 8.6kHz and in the voltage up to 14kV. The typical rise time is less than 300ns and the typical fall time is about 1.25μs.
2003,
15.
Abstract:
Beam profile and emittance are important parameters in storage ring. And progress the research of beam unstable on ring using beam profile monitoring system. The paper presents part reconstruction of the beam profile monitor system and its software update for Hefei light source. It is emphasizes on the software ROOT from CERN with its application in processing data and display.
Beam profile and emittance are important parameters in storage ring. And progress the research of beam unstable on ring using beam profile monitoring system. The paper presents part reconstruction of the beam profile monitor system and its software update for Hefei light source. It is emphasizes on the software ROOT from CERN with its application in processing data and display.
2003,
15.
Abstract:
For a deeper understanding of the physical process of plasma jetting on wire the one dimension magnetohydrodynamics simulation code under Lagrangian coordinates is used. It is detailed that the axial Al wire heated by shock wave expends after collision and finally pinches on the axis. A large value of current rate of rise is got on the axial wire according to our calculations. The resultant pinch according to our calculation outputs more X-ray energy and higher power.
For a deeper understanding of the physical process of plasma jetting on wire the one dimension magnetohydrodynamics simulation code under Lagrangian coordinates is used. It is detailed that the axial Al wire heated by shock wave expends after collision and finally pinches on the axis. A large value of current rate of rise is got on the axial wire according to our calculations. The resultant pinch according to our calculation outputs more X-ray energy and higher power.
2003,
15.
Abstract:
Surface flashover of insulators is widely applied in pulsed power technique. In the ion diode, polyethylence (PE) film is often used as anode foil, for it's abounding in hydrogen. As a flashover ion source, the formation of anode plasma influences the quantity and quality of ion beam seriously. A set of apparatus for studying flashover behavior of PE film in vacuum and it's measurement system are developed in our work. The experiment results of three PE films with difference thickness under impulse voltage of about 100kV, 40ns are presented. For the 90 and 65μm PE fil, if the maximal electric field be up to 150.5kV/cm and 145.3kV/cm respectively, flachover will occur. The luminescence phenomenon of film surface is also studied preliminarily.
Surface flashover of insulators is widely applied in pulsed power technique. In the ion diode, polyethylence (PE) film is often used as anode foil, for it's abounding in hydrogen. As a flashover ion source, the formation of anode plasma influences the quantity and quality of ion beam seriously. A set of apparatus for studying flashover behavior of PE film in vacuum and it's measurement system are developed in our work. The experiment results of three PE films with difference thickness under impulse voltage of about 100kV, 40ns are presented. For the 90 and 65μm PE fil, if the maximal electric field be up to 150.5kV/cm and 145.3kV/cm respectively, flachover will occur. The luminescence phenomenon of film surface is also studied preliminarily.
