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RSS2006 Vol. 18, No. 01
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2006,
18.
Abstract:
A new method for real-time detecting the rotation speed of high-speed rotating-mirror camera is proposed. This method acquires the time information of the rotating mirror by the laser’s capability of resisting the magnetic interference and being processed quickly. In order to gain a stable signal, an amplifier with limiting amplitude is needed to accommodate the wide range of the receiver power of the detector. An ASIC counter unit is adopted to meet the precision requirement and an embodied control module is used to realize the human-computer interaction conveniently. The experimental results show that the error can be restricted to nanosecond level and this system can improve one order of sensing precision than other sensing systems.
A new method for real-time detecting the rotation speed of high-speed rotating-mirror camera is proposed. This method acquires the time information of the rotating mirror by the laser’s capability of resisting the magnetic interference and being processed quickly. In order to gain a stable signal, an amplifier with limiting amplitude is needed to accommodate the wide range of the receiver power of the detector. An ASIC counter unit is adopted to meet the precision requirement and an embodied control module is used to realize the human-computer interaction conveniently. The experimental results show that the error can be restricted to nanosecond level and this system can improve one order of sensing precision than other sensing systems.
2006,
18.
Abstract:
Based on a continuous-membrane bulk-micromachined silicon deformable mirror, the paper summarizes the manufacture process of the deformable mirror. Electro-mechanical coupled analysis is presented in detail. Starting from the thin film theory, a universal expression which describes the mirror deflection is finally obtained as well. The relationship between mirror structure parameters and the mirror deflection described by the universal expression can be used to assist in designing mirrors for various applications. The results show that when a 1 μm thick mirror with 20 μm actuator gap is required to work with an actuator voltage less than 120 V and a resonant frequency higher than 50 kHz , the deformable mirror radius should be limited between 21 mm and 13.8 mm. The simulation result re
Based on a continuous-membrane bulk-micromachined silicon deformable mirror, the paper summarizes the manufacture process of the deformable mirror. Electro-mechanical coupled analysis is presented in detail. Starting from the thin film theory, a universal expression which describes the mirror deflection is finally obtained as well. The relationship between mirror structure parameters and the mirror deflection described by the universal expression can be used to assist in designing mirrors for various applications. The results show that when a 1 μm thick mirror with 20 μm actuator gap is required to work with an actuator voltage less than 120 V and a resonant frequency higher than 50 kHz , the deformable mirror radius should be limited between 21 mm and 13.8 mm. The simulation result re
2006,
18.
Abstract:
Based on the nonlinear Schrdinger equation, a simulation was carried out to solve the problem of the signal-to-noise ratio being low. The research dealt with the influence of higher-order dispersion, spectral modulation and self-phase-modulation on the signal to noise ratio. Furthermore, a physical model was built to analyze the impact of the flatness of gratings. The results show that for a 100 fs input Gaussian pulse, in order to make the signal-to-noise ratio bigger than 108, the third-order-dispersion should be kept below 4.8×105 fs3, the B-integral below 0.2, the amplitude of the modulation of spectrum below 10-4 and the flatness of gratings smaller than λ/100 .
Based on the nonlinear Schrdinger equation, a simulation was carried out to solve the problem of the signal-to-noise ratio being low. The research dealt with the influence of higher-order dispersion, spectral modulation and self-phase-modulation on the signal to noise ratio. Furthermore, a physical model was built to analyze the impact of the flatness of gratings. The results show that for a 100 fs input Gaussian pulse, in order to make the signal-to-noise ratio bigger than 108, the third-order-dispersion should be kept below 4.8×105 fs3, the B-integral below 0.2, the amplitude of the modulation of spectrum below 10-4 and the flatness of gratings smaller than λ/100 .
2006,
18.
Abstract:
The temperature distribution in the small diffusion region induced by laser is nonuniform, and the distribution of impurity concentration is nonuniform too. It was proposed to homogenize the distribution of impurity concentration through integration effects of multi laser induced diffusions. In laser induced selective Zn diffusion in InP, a computer controlled system was used to measure and control the temperature of the small exposed region. The distribution of impurity concentration in the overlapped region of twice irradiations was calculated according to the temperature distribution in the heated region. When the distance between the two adjacent laser irradiation position was 20 μm, the homogenization of one dimension by digital simulation was perfect. This work is fundamental for im
The temperature distribution in the small diffusion region induced by laser is nonuniform, and the distribution of impurity concentration is nonuniform too. It was proposed to homogenize the distribution of impurity concentration through integration effects of multi laser induced diffusions. In laser induced selective Zn diffusion in InP, a computer controlled system was used to measure and control the temperature of the small exposed region. The distribution of impurity concentration in the overlapped region of twice irradiations was calculated according to the temperature distribution in the heated region. When the distance between the two adjacent laser irradiation position was 20 μm, the homogenization of one dimension by digital simulation was perfect. This work is fundamental for im
2006,
18.
Abstract:
A verti-COIL with/without primary buffer gases was demonstrated in our laboratory. This verti-COIL represents the trend of less primary gases than traditional COIL. In the initial experimental stage, an output power of 1.3 kW and a chemical efficiency of 16.9% were obtained for a chlorine flowrate of 82 mmol/s, and its main parameters were compared with that of He-COIL (an output power of 2.4 kW and a chemical efficiency of 24% were obtained for a chlorine flowrate of 110 mmol/s) and that of N2-COIL (an output power of 2.38 kW and a chemical efficiency of 22.7% were obtained for a chlorine flowrate of 115 mmol/s). Primary experimental investigation indicated that, if the verti-COIL would have further reduced pτres value in SOG, and shortened I2/O2 mixing length in subsonic section or inje
A verti-COIL with/without primary buffer gases was demonstrated in our laboratory. This verti-COIL represents the trend of less primary gases than traditional COIL. In the initial experimental stage, an output power of 1.3 kW and a chemical efficiency of 16.9% were obtained for a chlorine flowrate of 82 mmol/s, and its main parameters were compared with that of He-COIL (an output power of 2.4 kW and a chemical efficiency of 24% were obtained for a chlorine flowrate of 110 mmol/s) and that of N2-COIL (an output power of 2.38 kW and a chemical efficiency of 22.7% were obtained for a chlorine flowrate of 115 mmol/s). Primary experimental investigation indicated that, if the verti-COIL would have further reduced pτres value in SOG, and shortened I2/O2 mixing length in subsonic section or inje
2006,
18.
Abstract:
Since laser beam has great brightness and good orientation, there are more and more applications in the industrial and military fields. Based on the merits of laser, the laser jamming to the target acquiring and tracking system with modulator was studied by experiment and simulation. In these experiments, the key parameters of laser system are output power and the laser pulse frequency. The laser jamming mechanism was studied by changing the output power and pulse frequency. After the experiments, the detailed analysis was done and some valuable conclusions were made. And based on the laser pulse reflected from the modulator surface, the rotate speed of the modulator was determined.
Since laser beam has great brightness and good orientation, there are more and more applications in the industrial and military fields. Based on the merits of laser, the laser jamming to the target acquiring and tracking system with modulator was studied by experiment and simulation. In these experiments, the key parameters of laser system are output power and the laser pulse frequency. The laser jamming mechanism was studied by changing the output power and pulse frequency. After the experiments, the detailed analysis was done and some valuable conclusions were made. And based on the laser pulse reflected from the modulator surface, the rotate speed of the modulator was determined.
2006,
18.
Abstract:
A fast time-resolved aberration wavefront reconstruction method named SABT has been applied in the study of aero-optics. The introduction of scale-independent convection velocity hypothesis results in the wavefront measured errors. The measured signals were multi-scale decomposed by wavelet analysis and the scale-dependent convection velocities are computed with correlation method, then the scale-dependent convection velocities are used to reconstruct the wavefronts. The results indicate that the scale-dependent SABT can improve the precision of wavefront reconstruction than single convection velocity SABT.
A fast time-resolved aberration wavefront reconstruction method named SABT has been applied in the study of aero-optics. The introduction of scale-independent convection velocity hypothesis results in the wavefront measured errors. The measured signals were multi-scale decomposed by wavelet analysis and the scale-dependent convection velocities are computed with correlation method, then the scale-dependent convection velocities are used to reconstruct the wavefronts. The results indicate that the scale-dependent SABT can improve the precision of wavefront reconstruction than single convection velocity SABT.
2006,
18.
Abstract:
The 1 064 nm Doppler wind lidar with a dual Fabry-Perot interferometer based on the edge technique has been developed to measure the wind profile in the troposphere. The construction of the lidar system is described. The dual interferometer with high-spectral resolution is used to discriminate the Doppler shift from the aerosol backscattering. The accuracy of the lidar system is analyzed and discussed especially for the interferometer parameters. The transmittance curve of the interferometer is measured and the standard deviation of the transmittance will cause a velocity error of 0.5 m/s. The result of the analysis show that the error of the lidar measurement ranges from less than 2 m/s up to 10 km for the wind velocity of 50 m/s and the error increases with the increase of the radial vel
The 1 064 nm Doppler wind lidar with a dual Fabry-Perot interferometer based on the edge technique has been developed to measure the wind profile in the troposphere. The construction of the lidar system is described. The dual interferometer with high-spectral resolution is used to discriminate the Doppler shift from the aerosol backscattering. The accuracy of the lidar system is analyzed and discussed especially for the interferometer parameters. The transmittance curve of the interferometer is measured and the standard deviation of the transmittance will cause a velocity error of 0.5 m/s. The result of the analysis show that the error of the lidar measurement ranges from less than 2 m/s up to 10 km for the wind velocity of 50 m/s and the error increases with the increase of the radial vel
2006,
18.
Abstract:
In transfer and amplification system of laser, spatial filtering is a key to improving the quality of output light. Based on rotation effects of polarized light in an isotropic crystal, the polarized light with spatial variation components might pass through or be cut off by polarization selectivity, spatial filtering of light in near-field is feasible. Furthermore, combined filters can improve narrow-band filtering. The proposed method is able to reduce the system space and energy consumption in the spatial filtering system.
In transfer and amplification system of laser, spatial filtering is a key to improving the quality of output light. Based on rotation effects of polarized light in an isotropic crystal, the polarized light with spatial variation components might pass through or be cut off by polarization selectivity, spatial filtering of light in near-field is feasible. Furthermore, combined filters can improve narrow-band filtering. The proposed method is able to reduce the system space and energy consumption in the spatial filtering system.
2006,
18.
Abstract:
The picosecond transient sampling gate is mainly applied in laser fusion and high energy physics experiments for single high-speed pulse real-time sampling. A new balanced sampling gate based on monolithic Schottky bridge quad diodes is put forward in this paper as well as its model and circuit design. The circuit simulation shows that the symmetric strobe design ensures that the sampling interval is 100 ps and the sampling gate bandwidth is 4.4 GHz when the strobe pulse width is 100 ps. The gate can be used in multi-beam ultrashort laser pulses sampling.
The picosecond transient sampling gate is mainly applied in laser fusion and high energy physics experiments for single high-speed pulse real-time sampling. A new balanced sampling gate based on monolithic Schottky bridge quad diodes is put forward in this paper as well as its model and circuit design. The circuit simulation shows that the symmetric strobe design ensures that the sampling interval is 100 ps and the sampling gate bandwidth is 4.4 GHz when the strobe pulse width is 100 ps. The gate can be used in multi-beam ultrashort laser pulses sampling.
2006,
18.
Abstract:
A method of super-resolution imaging is described ,which utilizes cosine fringes to acquire more spatial frequency spectrum of the object. The spatial frequency of the object illuminated by the cosine fringes is shifted, thus a portion of high frequency components beyond the cutoff frequency could pass through the optical system. The image is achieved separately after illuminating many fringes, which has the same spatial frequency but different phase. Then the images are processed to separate the frequency components and reconstruct the original spectrum. Finally, the computer simulation demonstrates the feasibility of the new technique.
A method of super-resolution imaging is described ,which utilizes cosine fringes to acquire more spatial frequency spectrum of the object. The spatial frequency of the object illuminated by the cosine fringes is shifted, thus a portion of high frequency components beyond the cutoff frequency could pass through the optical system. The image is achieved separately after illuminating many fringes, which has the same spatial frequency but different phase. Then the images are processed to separate the frequency components and reconstruct the original spectrum. Finally, the computer simulation demonstrates the feasibility of the new technique.
2006,
18.
Abstract:
The method and experimental process to calibrate the energy of electron beam by resonant depolarization is discussed in this paper. As a characteristic function of spin dynamics, spin response function is an indispensable parameter of depolarization time. The spin response function at Hefei electron storage ring was calculated, and the result of spin response function in a period of the ring was presented. In the experiment of spin depolarization to calibrate HLS beam energy, the spin response function in the position of depolarization is 1.569 m, and the depolarization time is 60 s.
The method and experimental process to calibrate the energy of electron beam by resonant depolarization is discussed in this paper. As a characteristic function of spin dynamics, spin response function is an indispensable parameter of depolarization time. The spin response function at Hefei electron storage ring was calculated, and the result of spin response function in a period of the ring was presented. In the experiment of spin depolarization to calibrate HLS beam energy, the spin response function in the position of depolarization is 1.569 m, and the depolarization time is 60 s.
2006,
18.
Abstract:
By analyzing lumped circuit of loaded resonant cavity, a new method of calculating external Q was advanced. In this way the resonant frequency and external Q can be determined with the reflected phase calculated in frequency domain. The particular calculations of reflected phase method, eigenmode method and time domain tracking method were shown in the software CST Microwave Studio. The three methods mentioned above were used to calculate the external Q of secondary emission microwave electron gun. Comparing the calculation results with measured data, it is indicated that these three methods are the same in high precision, but the calculating speed of reflected phase method is the quickest, whose calculating time is 1 071 s. At last, it is found that external Q is in inverse proportion to
By analyzing lumped circuit of loaded resonant cavity, a new method of calculating external Q was advanced. In this way the resonant frequency and external Q can be determined with the reflected phase calculated in frequency domain. The particular calculations of reflected phase method, eigenmode method and time domain tracking method were shown in the software CST Microwave Studio. The three methods mentioned above were used to calculate the external Q of secondary emission microwave electron gun. Comparing the calculation results with measured data, it is indicated that these three methods are the same in high precision, but the calculating speed of reflected phase method is the quickest, whose calculating time is 1 071 s. At last, it is found that external Q is in inverse proportion to
2006,
18.
Abstract:
In order to decrease the edge effect of the field, the designed magnetic field distribution in a large-scale FFAG magnet is realized by both the trim coil and the shape of the magnet pole-face. Through two-dimensional POISSON simulations, the distribution about the current and the position of the trim coil and the shape of the magnet pole are determined. In order to facilitate the POISSON design, two codes are written to automatically adjust the current and the position of the trim coil and the shape of magnet pole-face appeared in the POISSON input file. With the two codes, the efficiency of POISSON simulations is improved and the mistakes which might occur in writing and adjusting the POISSON input file manually could be avoided.
In order to decrease the edge effect of the field, the designed magnetic field distribution in a large-scale FFAG magnet is realized by both the trim coil and the shape of the magnet pole-face. Through two-dimensional POISSON simulations, the distribution about the current and the position of the trim coil and the shape of the magnet pole are determined. In order to facilitate the POISSON design, two codes are written to automatically adjust the current and the position of the trim coil and the shape of magnet pole-face appeared in the POISSON input file. With the two codes, the efficiency of POISSON simulations is improved and the mistakes which might occur in writing and adjusting the POISSON input file manually could be avoided.
2006,
18.
Abstract:
For induction accelerating cavity, there are two pulse power feed-in methods: the axial method and the radial method. The effects of different pulse power feed-in methods on the flat-top voltage width of induction accelerating cavities were analyzed and some experiments were carried out to prove this analysis. In the experiments, one Blumlein PFL was used to feed-in “axial” cavity and “radial” cavity at the same time, and a 62 ns width was obtained in the “axial” cavity and a 61 ns width in the “radial” cavity for ±1% voltage flat-top. In additional, the two cavities’ transverse impedances were calculated, and the result showed that the “axial” cavity had lower transverse impedance than the “radial” cavity.
For induction accelerating cavity, there are two pulse power feed-in methods: the axial method and the radial method. The effects of different pulse power feed-in methods on the flat-top voltage width of induction accelerating cavities were analyzed and some experiments were carried out to prove this analysis. In the experiments, one Blumlein PFL was used to feed-in “axial” cavity and “radial” cavity at the same time, and a 62 ns width was obtained in the “axial” cavity and a 61 ns width in the “radial” cavity for ±1% voltage flat-top. In additional, the two cavities’ transverse impedances were calculated, and the result showed that the “axial” cavity had lower transverse impedance than the “radial” cavity.
2006,
18.
Abstract:
Magnetic compressor is a very important part for SASE FEL facility at Peking University (PKU SASE FEL), which is used to produce short electron bunches in order to satisfy fast lasing saturation of SASE in undulator. In this paper, the fundamental principle of magnetic compression is analyzed, which shows that the effect of bunch compression is closely related with the RF instability. By using the design parameters of magnetic chicane of PKU SASE FEL, the impact on the magnetic compression due to RF instability is given. The final bunch length will change due to RF instability. So, a gool for RF instability control is proposed according to the requirement of PKU FEL.
Magnetic compressor is a very important part for SASE FEL facility at Peking University (PKU SASE FEL), which is used to produce short electron bunches in order to satisfy fast lasing saturation of SASE in undulator. In this paper, the fundamental principle of magnetic compression is analyzed, which shows that the effect of bunch compression is closely related with the RF instability. By using the design parameters of magnetic chicane of PKU SASE FEL, the impact on the magnetic compression due to RF instability is given. The final bunch length will change due to RF instability. So, a gool for RF instability control is proposed according to the requirement of PKU FEL.
2006,
18.
Abstract:
This paper describes the design of a split photon beam position monitor at HLS (Hefei Light Source). Two methods of position processing are given and compared. The monitor is tested and calibrated, the results are well matched with the computed results. The photon beam position monitor has been successfully used to soft X-ray Magnetic Circular Dichroism(MCD) beam-line U18, such as the measurement of orbit stability and the slow local orbit feedback. The results of these applications are given.
This paper describes the design of a split photon beam position monitor at HLS (Hefei Light Source). Two methods of position processing are given and compared. The monitor is tested and calibrated, the results are well matched with the computed results. The photon beam position monitor has been successfully used to soft X-ray Magnetic Circular Dichroism(MCD) beam-line U18, such as the measurement of orbit stability and the slow local orbit feedback. The results of these applications are given.
2006,
18.
Abstract:
The theoretic design, the 2-D magnetic field calculation and the electrical calculation of a kicker magnet for CSRm extraction are described as well as the construction design and the manufacture of some key parts. In order to decrease the additional inductance of the magnet, a one-turn coil and ferrite cores are used in the magnet. Each pair of the magnets are powered by a pair of pulse power supplies. The designed inductance is less than 1 μH and the field homogeneity is better than ±0.5% at the peak value of 0.038 T. The magnet meets all of the strict requirements.
The theoretic design, the 2-D magnetic field calculation and the electrical calculation of a kicker magnet for CSRm extraction are described as well as the construction design and the manufacture of some key parts. In order to decrease the additional inductance of the magnet, a one-turn coil and ferrite cores are used in the magnet. Each pair of the magnets are powered by a pair of pulse power supplies. The designed inductance is less than 1 μH and the field homogeneity is better than ±0.5% at the peak value of 0.038 T. The magnet meets all of the strict requirements.
2006,
18.
Abstract:
A low-prepulse and high-power water dielectric self-breaking switch was investigated on Flash Ⅱ generator, whose breakdown voltage was from 1.0 to 1.5 MV and discharge current was from 200 to 550 kA. The rise time of the discharge current was about 60 ns and pulse duration(FWHM) was 150 ns. The discharge current of each gap was measured by Rogowski coil and the input voltage and the output voltage were measured by CuSO4 resistance divider. The calculation result was compared with the demarcation results of divider ratio and the reason of producing error was analyzed. Some pieces of advice about experiment were presented: (1)Rogowski coil must be separated from water. (2)The divider ratio of the first stage of the CuSO4 resistance divider should not be too great. (3)The concentration of Cu
A low-prepulse and high-power water dielectric self-breaking switch was investigated on Flash Ⅱ generator, whose breakdown voltage was from 1.0 to 1.5 MV and discharge current was from 200 to 550 kA. The rise time of the discharge current was about 60 ns and pulse duration(FWHM) was 150 ns. The discharge current of each gap was measured by Rogowski coil and the input voltage and the output voltage were measured by CuSO4 resistance divider. The calculation result was compared with the demarcation results of divider ratio and the reason of producing error was analyzed. Some pieces of advice about experiment were presented: (1)Rogowski coil must be separated from water. (2)The divider ratio of the first stage of the CuSO4 resistance divider should not be too great. (3)The concentration of Cu
2006,
18.
Abstract:
Based on a one-dimensional hydrodynamics model in which the power deposition is calculated through the kinetics theory, the spatial distributions profile of the plasma density and the electron temperature in the inductively coupled plasma (ICP), were simulated and the influences of the discharge pressure and the coil current on the plasma density and electron temperature were discussed. It has been found that at low pressures, the distributions of the plasma density are basically spatial homogeneity, except near the edge of the discharge equipment. As the pressure increases, the plasma density distribution tends to be evidently spatial inhomogeneous. Both the plasma density and the electron temperature increase as the coil current increases.
Based on a one-dimensional hydrodynamics model in which the power deposition is calculated through the kinetics theory, the spatial distributions profile of the plasma density and the electron temperature in the inductively coupled plasma (ICP), were simulated and the influences of the discharge pressure and the coil current on the plasma density and electron temperature were discussed. It has been found that at low pressures, the distributions of the plasma density are basically spatial homogeneity, except near the edge of the discharge equipment. As the pressure increases, the plasma density distribution tends to be evidently spatial inhomogeneous. Both the plasma density and the electron temperature increase as the coil current increases.
2006,
18.
Abstract:
The nanocrystalline Cu was prepared by flow-levitation-cold-pressing method under different pressures and then annealed at different temperatures with different annealing time. The X-ray diffraction (XRD) and positron annihilation spectroscopy (PAS) were used to determine the structure and microdefects in the nanocrystallie Cu. The XRD analysis results show that the grain size of the specimen after being pressed is 20 nm and does not grow prominently after annealing below 300℃ for 3 h. The PAS analysis results show that most of the defects in the specimen after press is vacancies and vacancy-clusters, the amount of micro-voids is small; after being annealed at high temperature or for a long time, the vacancies aggregate together to form vacancy-cluster by diffusion, the micro-voids break
The nanocrystalline Cu was prepared by flow-levitation-cold-pressing method under different pressures and then annealed at different temperatures with different annealing time. The X-ray diffraction (XRD) and positron annihilation spectroscopy (PAS) were used to determine the structure and microdefects in the nanocrystallie Cu. The XRD analysis results show that the grain size of the specimen after being pressed is 20 nm and does not grow prominently after annealing below 300℃ for 3 h. The PAS analysis results show that most of the defects in the specimen after press is vacancies and vacancy-clusters, the amount of micro-voids is small; after being annealed at high temperature or for a long time, the vacancies aggregate together to form vacancy-cluster by diffusion, the micro-voids break
2006,
18.
Abstract:
The effect of proton radiation with the energy of 100 keV and 150 keV on thermal properties of additional silicone rubber reinforced with MQ resin by space combined radiation simulator was studied in this paper. The results showed that the aging crackle was produced on the surface of rubber after irradiation and the quantity and size of the crackle increased with the increase of irradiation energy and fluence. There was mass loss of silicon rubber after proton radiation and the mass loss percent increased with the increase of irradiation fluence. The thermostability of silicone rubber increased slightly first and then decreased with the increase of irradiation fluence. The shrinkage of silicone rubber reduced in the temperature range of vitreous state and vitrification transition region af
The effect of proton radiation with the energy of 100 keV and 150 keV on thermal properties of additional silicone rubber reinforced with MQ resin by space combined radiation simulator was studied in this paper. The results showed that the aging crackle was produced on the surface of rubber after irradiation and the quantity and size of the crackle increased with the increase of irradiation energy and fluence. There was mass loss of silicon rubber after proton radiation and the mass loss percent increased with the increase of irradiation fluence. The thermostability of silicone rubber increased slightly first and then decreased with the increase of irradiation fluence. The shrinkage of silicone rubber reduced in the temperature range of vitreous state and vitrification transition region af
2006,
18.
Abstract:
Al doped ZnO thin films were fabricated on quartz substrates by sol-gel method. An X-ray diffraction (XRD) was used to analyse the structural properties of the thin films. All the thin films have a preferential c-axis orientation, which enhances in the annealing process. From the spectrometer transmittance data, the optical absorption of AZO films was found to have a redshift with an increase in annealing temperature. From the PL measurement the near band edge (NBE) emission and deep-level (DL) emission are observed in unannealed AZO thin films. However, after annealing at high temperature, the DL emissions of the thin films are depressed. As the annealing temperature increases, the peak of NBE emission has a shift to region of lower photon energy, which is coincident with the results from
Al doped ZnO thin films were fabricated on quartz substrates by sol-gel method. An X-ray diffraction (XRD) was used to analyse the structural properties of the thin films. All the thin films have a preferential c-axis orientation, which enhances in the annealing process. From the spectrometer transmittance data, the optical absorption of AZO films was found to have a redshift with an increase in annealing temperature. From the PL measurement the near band edge (NBE) emission and deep-level (DL) emission are observed in unannealed AZO thin films. However, after annealing at high temperature, the DL emissions of the thin films are depressed. As the annealing temperature increases, the peak of NBE emission has a shift to region of lower photon energy, which is coincident with the results from
2006,
18.
Abstract:
A flat model is used to further study the scatter law in the X-ray radiography. The results are obtained with the analytic method and the MC simulations. One shows that in the radiography the Compton scatter is the dominant mode of interactions between the photon and the material and the first Compton scatter is more than 75 percent of the total scatter when the optical path of the flat is less than 2.0. And the analytic model is established effectively with the first Compton scatter approximation to the total. Another is that the same conclusion, which is the optical path of the flat is between 1.0 and 2.0 when the maximum scatter happens, is gained by analytic method, MC method with first Compton scatter and MC method with total scatter, respectively.
A flat model is used to further study the scatter law in the X-ray radiography. The results are obtained with the analytic method and the MC simulations. One shows that in the radiography the Compton scatter is the dominant mode of interactions between the photon and the material and the first Compton scatter is more than 75 percent of the total scatter when the optical path of the flat is less than 2.0. And the analytic model is established effectively with the first Compton scatter approximation to the total. Another is that the same conclusion, which is the optical path of the flat is between 1.0 and 2.0 when the maximum scatter happens, is gained by analytic method, MC method with first Compton scatter and MC method with total scatter, respectively.
2006,
18.
Abstract:
The parameters that affect the transformation process from dried-gel to microshell and the hollow glass microsphere (HGM) quality were investigated. The results show that increasing the volume fraction of Helium in furnace atmosphere can raise HGM yield and aspect ratio, but increasing the volume fraction of Argon properly is favorable for HGM surface finish. Decreasing furnace atmosphere pressure will increase HGM aspect ratio. HGM yield and quality increase with the increase of the furnace atmosphere temperature. When the volume fraction of helium in furnace atmosphere ranges from 50% to 80%, the furnace atmosphere pressure from 0.75×105 Pa to 1.00×105 Pa, the furnace atmosphere temperature from 1 500 ℃ to 1 650 ℃, high-quality HGM can be fabricated with high yield. Under the above o
The parameters that affect the transformation process from dried-gel to microshell and the hollow glass microsphere (HGM) quality were investigated. The results show that increasing the volume fraction of Helium in furnace atmosphere can raise HGM yield and aspect ratio, but increasing the volume fraction of Argon properly is favorable for HGM surface finish. Decreasing furnace atmosphere pressure will increase HGM aspect ratio. HGM yield and quality increase with the increase of the furnace atmosphere temperature. When the volume fraction of helium in furnace atmosphere ranges from 50% to 80%, the furnace atmosphere pressure from 0.75×105 Pa to 1.00×105 Pa, the furnace atmosphere temperature from 1 500 ℃ to 1 650 ℃, high-quality HGM can be fabricated with high yield. Under the above o
2006,
18.
Abstract:
Supersonic technique was introduced into the synthetic route of resorcinol-formaldehyde(RF) aerogel to shorten the fabrication period. The effects of supersonic on gelating and solvent exchanging process were studied. The gelating time by supersonic was shorten by 8%～17% in 10% RF solution. In diluted RF solution, the growth of gel nucleus by supersonic irradiation was about 87 times the velocity of that heating. Supersonic restrained the oxidation effect of reactant in the gelating process. Low intensity supersonic wave speeded up the water exchange by 10 000 times in the solvent exchanging process.
Supersonic technique was introduced into the synthetic route of resorcinol-formaldehyde(RF) aerogel to shorten the fabrication period. The effects of supersonic on gelating and solvent exchanging process were studied. The gelating time by supersonic was shorten by 8%～17% in 10% RF solution. In diluted RF solution, the growth of gel nucleus by supersonic irradiation was about 87 times the velocity of that heating. Supersonic restrained the oxidation effect of reactant in the gelating process. Low intensity supersonic wave speeded up the water exchange by 10 000 times in the solvent exchanging process.
2006,
18.
Abstract:
An important diagnosis method——Kirkpatrick-Baez microscope system in ICF experiments was researched. The brief aberration of the Kirkpatrick-Baez microscope was calculated. The main aberration, spherical aberration was analyzed, and the spherical aberration is 94% of the total aberration. The configuration was simulated by the ray tracing method. Resolutions in different fields and mirror-lengths were compared. The modal of Kirkpatrick-Baez microscope was made in computer with 10 μm resolutionat 8 keV. It was studied about the adjusting tolerance method of Kirkpatrick-Baez microscope. When numerical aperture is 0.003 7, the angle error range is -0.087°~0.067°。
An important diagnosis method——Kirkpatrick-Baez microscope system in ICF experiments was researched. The brief aberration of the Kirkpatrick-Baez microscope was calculated. The main aberration, spherical aberration was analyzed, and the spherical aberration is 94% of the total aberration. The configuration was simulated by the ray tracing method. Resolutions in different fields and mirror-lengths were compared. The modal of Kirkpatrick-Baez microscope was made in computer with 10 μm resolutionat 8 keV. It was studied about the adjusting tolerance method of Kirkpatrick-Baez microscope. When numerical aperture is 0.003 7, the angle error range is -0.087°~0.067°。
2006,
18.
Abstract:
A new fringe-pattern preprocess based on median spin filter is proposed to deal with the interferogram with high-level noises. It only smoothes noises in fringe-tangential direction by median filter, therefore, it can filter off noises such as coherent artifacts, additive random noise, “Salt and pepper” and large bright and black spots, without blurring and distorting the fringe-pattern features. The experimental results show that the median spin filter is suitable for the interferogram with all kinds of noise, especially the random noise, speckle noise and large bright or black spots. The method is better than Gerchberg's extrapolation algorithm and filters in frequency space when dealing with large bright or black spots. The P-V and RMS errors are less than 1.5% and 2.3% for 95% apertu
A new fringe-pattern preprocess based on median spin filter is proposed to deal with the interferogram with high-level noises. It only smoothes noises in fringe-tangential direction by median filter, therefore, it can filter off noises such as coherent artifacts, additive random noise, “Salt and pepper” and large bright and black spots, without blurring and distorting the fringe-pattern features. The experimental results show that the median spin filter is suitable for the interferogram with all kinds of noise, especially the random noise, speckle noise and large bright or black spots. The method is better than Gerchberg's extrapolation algorithm and filters in frequency space when dealing with large bright or black spots. The P-V and RMS errors are less than 1.5% and 2.3% for 95% apertu
2006,
18.
Abstract:
The design, research and test of a metallized dielectric capacitor in Guilin Power Capacitor Corporation(GCC) for SGⅢ prototype laser facility began nearly seven years ago. The MKMJ25—55(25 kV,55 μF,0.56 J/cm3) capacitor, made by GCC, has been successfully utilized in SGⅢ prototype. This paper describes the metallized dielectric configuration, performance of the capacitor and testing and explores its lifetime and failure mechanism. Experiments show that it has a capacitance tolerance of 2%~5% and a dissipation factor lower than 0.05%. It has good dielectric strength since it withstood electrode-electrode and electrode-ground voltages. The capacitance dropped 1.8% after 1×104 charge-discharge cycles in lifetime test.
The design, research and test of a metallized dielectric capacitor in Guilin Power Capacitor Corporation(GCC) for SGⅢ prototype laser facility began nearly seven years ago. The MKMJ25—55(25 kV,55 μF,0.56 J/cm3) capacitor, made by GCC, has been successfully utilized in SGⅢ prototype. This paper describes the metallized dielectric configuration, performance of the capacitor and testing and explores its lifetime and failure mechanism. Experiments show that it has a capacitance tolerance of 2%~5% and a dissipation factor lower than 0.05%. It has good dielectric strength since it withstood electrode-electrode and electrode-ground voltages. The capacitance dropped 1.8% after 1×104 charge-discharge cycles in lifetime test.
2006,
18.
Abstract:
The preparation of beryllium hydride materials is described and the structure and the physical and chemical properties are analyzed in the paper. Its application in inertial confinement fusion is analyzed. The beryllium hydride materials are mainly produced by pyrolysis of di-tert-butyl beryllium and by CVD from elements. The structure of amorphous beryllium hydride is a network structure of corner-sharing BeH4 tetrahedron. Amorphous beryllium hydride can reduce the probability of Raighley-Taylor instability and diminish preheating of a DT-mixture by introduction of heavy-elements. Amorphous beryllium hydride, as ablator, can increase conversion from laser to X-rays.
The preparation of beryllium hydride materials is described and the structure and the physical and chemical properties are analyzed in the paper. Its application in inertial confinement fusion is analyzed. The beryllium hydride materials are mainly produced by pyrolysis of di-tert-butyl beryllium and by CVD from elements. The structure of amorphous beryllium hydride is a network structure of corner-sharing BeH4 tetrahedron. Amorphous beryllium hydride can reduce the probability of Raighley-Taylor instability and diminish preheating of a DT-mixture by introduction of heavy-elements. Amorphous beryllium hydride, as ablator, can increase conversion from laser to X-rays.
2006,
18.
Abstract:
This paper introduced a new technique about calibration of a single-photon counting X-ray CCD. The principle of the CCD was described. In the calibration experiment, several standard X-ray sources were adopted to radiate forward the CCD detector and the counts occured. When the CCD was in a state of single-photon counting, the X-ray intensity was obtained with integral. After deducting the background, the photon energy of 6.453 eV that produced one count was calibrated. Based on this result, the detection efficiency of the CCD was calculated. The detection efficiency changed with photon energies in the range of 5.3~30 keV. The efficiency decreased with the increase of the photon energy.
This paper introduced a new technique about calibration of a single-photon counting X-ray CCD. The principle of the CCD was described. In the calibration experiment, several standard X-ray sources were adopted to radiate forward the CCD detector and the counts occured. When the CCD was in a state of single-photon counting, the X-ray intensity was obtained with integral. After deducting the background, the photon energy of 6.453 eV that produced one count was calibrated. Based on this result, the detection efficiency of the CCD was calculated. The detection efficiency changed with photon energies in the range of 5.3~30 keV. The efficiency decreased with the increase of the photon energy.
2006,
18.
Abstract:
Principles of cold rolling with multi-high cold-rolling mill are introduced in this text and Titanium film with thickness less than 1.5 μm has been made with the 32-high cold-rollin mill. The roughness of the rolled film is closely associated with the roughness of the work roller. Thin film with roughness of 25.2 nm has been made with the roughness lower of the work roller. The technology of cold-rolling with multi-roller mill has been used in the fabrication of target materials as Cu, Al, etc.
Principles of cold rolling with multi-high cold-rolling mill are introduced in this text and Titanium film with thickness less than 1.5 μm has been made with the 32-high cold-rollin mill. The roughness of the rolled film is closely associated with the roughness of the work roller. Thin film with roughness of 25.2 nm has been made with the roughness lower of the work roller. The technology of cold-rolling with multi-roller mill has been used in the fabrication of target materials as Cu, Al, etc.
2006,
18.
Abstract:
The FDTD method and near-to far-field transformation based on Kirchhoff integral were used to calculate the induced open-circuit voltage of cables in free space exposed to HPM and UWB pulse. The influence of the parameters of incident waveform and the relation between the peak value of induced voltage and the length of cable were analyzed. The numerical results indicate that the induced voltage varies with the length of cable and the parameters of incident waveform. Variation of induced voltage peak value is not linear with the length of cable. When the length of cable reaches certain value, it is found that the induced voltage has a maximum peak value. With the electric field intensity of 50 kV·m-1, the peak value of induced voltage can come to several hundred volts even to several ten k
The FDTD method and near-to far-field transformation based on Kirchhoff integral were used to calculate the induced open-circuit voltage of cables in free space exposed to HPM and UWB pulse. The influence of the parameters of incident waveform and the relation between the peak value of induced voltage and the length of cable were analyzed. The numerical results indicate that the induced voltage varies with the length of cable and the parameters of incident waveform. Variation of induced voltage peak value is not linear with the length of cable. When the length of cable reaches certain value, it is found that the induced voltage has a maximum peak value. With the electric field intensity of 50 kV·m-1, the peak value of induced voltage can come to several hundred volts even to several ten k
2006,
18.
Abstract:
With the increase in power and miniaturization of TWT, the distribution of collector temperature and the cooling method have great effect on operation of TWT. The thermal performance of TWT collector is explored by simulation using ANSYS package. The ways of applying boundary condition that affect the distribution of collector temperature are compared. An overview of the thermal behavior for collectors with different structure and different cooling methods，such as free convection, forced convection, single and double channel water-cooling, etc., is given. The result estimated by simulation is consistent with the experiment and proves that the model and method employed are suitable.
With the increase in power and miniaturization of TWT, the distribution of collector temperature and the cooling method have great effect on operation of TWT. The thermal performance of TWT collector is explored by simulation using ANSYS package. The ways of applying boundary condition that affect the distribution of collector temperature are compared. An overview of the thermal behavior for collectors with different structure and different cooling methods，such as free convection, forced convection, single and double channel water-cooling, etc., is given. The result estimated by simulation is consistent with the experiment and proves that the model and method employed are suitable.
2006,
18.
Abstract:
A time-domain model of PIN diode limiter has been studied with PSpice code in this paper. The Q-I relationship of the I-region is obtained using the Laplace transform and Padé approximation based on the base area ambipolar carrier transport equation. The proposed limiter circuit model takes into account the input RF power, the pulse rising time and the width of the I-region. Simulation results and experimental studies show that PIN diode limiter spike leakage characters are determined on the microwave pulse power and rising time. It is a transient effect and might not be observed with a slow rising time pulse.
A time-domain model of PIN diode limiter has been studied with PSpice code in this paper. The Q-I relationship of the I-region is obtained using the Laplace transform and Padé approximation based on the base area ambipolar carrier transport equation. The proposed limiter circuit model takes into account the input RF power, the pulse rising time and the width of the I-region. Simulation results and experimental studies show that PIN diode limiter spike leakage characters are determined on the microwave pulse power and rising time. It is a transient effect and might not be observed with a slow rising time pulse.
2006,
18.
Abstract:
The cylindrical dipole antenna with a lumped resistive loading is considered as a radiator of ultra-wideband short-pulses. Specifically, the distribution and value of the resistance along the dipole antenna are proposed by Wu and King (Wu-King profile). This antenna is analyzed by using the finite-difference time-domain (FDTD) method. The electromagnetic field in the space surrounding the antenna is determined as a function of time, which can be used to calculate the current waveforms on the antenna, time-varying field in the far zone, and some important time domain parameters for describing the performance of the antenna. Graphical displays of these results are used to provide physical insight into the transient radiation processes of this antenna.
The cylindrical dipole antenna with a lumped resistive loading is considered as a radiator of ultra-wideband short-pulses. Specifically, the distribution and value of the resistance along the dipole antenna are proposed by Wu and King (Wu-King profile). This antenna is analyzed by using the finite-difference time-domain (FDTD) method. The electromagnetic field in the space surrounding the antenna is determined as a function of time, which can be used to calculate the current waveforms on the antenna, time-varying field in the far zone, and some important time domain parameters for describing the performance of the antenna. Graphical displays of these results are used to provide physical insight into the transient radiation processes of this antenna.
2006,
18.
Abstract:
A 3D electromagnetic field algorithm and the stability condition of the electromagnetic were analyzed based on the 3D Yee grid model and the leapfrog model. The average-weighting and charge-conserving ways to realize the interaction between electromagnetic and particles were discussed. At the same time the perfect conductor boundary condition, the free space absorbing boundary and explosive emission model were discussed. Finally, inward-emitting coaxial diode was used as an example to validate the simulation of current-voltage correlation and characteristics of electron beam movement.
A 3D electromagnetic field algorithm and the stability condition of the electromagnetic were analyzed based on the 3D Yee grid model and the leapfrog model. The average-weighting and charge-conserving ways to realize the interaction between electromagnetic and particles were discussed. At the same time the perfect conductor boundary condition, the free space absorbing boundary and explosive emission model were discussed. Finally, inward-emitting coaxial diode was used as an example to validate the simulation of current-voltage correlation and characteristics of electron beam movement.
2006,
18.
Abstract:
This paper presents an analysis of open cavity of C-band MILO. The eigenfrequency of the open cavity and Q factor of loaded-cavity are calculated by observing the response of the broad-band driver. The numerical method based on the finite difference method in time domain is applied to calculate the radial electric field of the open cavity within one period. The distribution of the field is divided into four regions, the cut-off region, the standing wave region, the transition region, and the traveling-wave region. The inherent Q factor and the loaded Q factor are also calculated.
This paper presents an analysis of open cavity of C-band MILO. The eigenfrequency of the open cavity and Q factor of loaded-cavity are calculated by observing the response of the broad-band driver. The numerical method based on the finite difference method in time domain is applied to calculate the radial electric field of the open cavity within one period. The distribution of the field is divided into four regions, the cut-off region, the standing wave region, the transition region, and the traveling-wave region. The inherent Q factor and the loaded Q factor are also calculated.
2006,
18.
Abstract:
The propagation characteristics of the repetition-rate high-power microwave (HPM) in atmosphere were studied theoretically, and the electron density expression at a point in atmosphere was educed after HPM pulses transmitting. The relationship between the number of the penetrated pulses and the microwave power was described under different atmospheric pressure and microwave pulse parameters. The simulation results indicate that the smaller the atmospheric pressure is, the smaller the number of the penetrated pulses is when air gets breakdown at the same microwave pulse parameters, and the wider the pulse width and the lower the microwave frequency, the smaller the number of the penetrated pulses.
The propagation characteristics of the repetition-rate high-power microwave (HPM) in atmosphere were studied theoretically, and the electron density expression at a point in atmosphere was educed after HPM pulses transmitting. The relationship between the number of the penetrated pulses and the microwave power was described under different atmospheric pressure and microwave pulse parameters. The simulation results indicate that the smaller the atmospheric pressure is, the smaller the number of the penetrated pulses is when air gets breakdown at the same microwave pulse parameters, and the wider the pulse width and the lower the microwave frequency, the smaller the number of the penetrated pulses.
2006,
18.
Abstract:
That the disconsistency between the plane one-dimension assumption and the law that the microwave energy flux per unit area is inversely proportional to the square of the propagation distance is pointed out. The fundamental equations of the HPM propagation in the atmosphere under the beam flux one-dimension assumption are given. The characteristics and scaling laws of the ionization atmosphere are studied in detail. When n/nc is not too small, the great difference on the tail-erosion between the plane one-dimension and the beam one-dimension assumptions is presented.
That the disconsistency between the plane one-dimension assumption and the law that the microwave energy flux per unit area is inversely proportional to the square of the propagation distance is pointed out. The fundamental equations of the HPM propagation in the atmosphere under the beam flux one-dimension assumption are given. The characteristics and scaling laws of the ionization atmosphere are studied in detail. When n/nc is not too small, the great difference on the tail-erosion between the plane one-dimension and the beam one-dimension assumptions is presented.
