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RSS2000 Vol. 12, No. 04
Recommend Articles
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2000,
12.
Abstract:
Termination match is a key for the design of transmission line. This paper, using Laplace transform method, describes exactly the transient transmission process of a Blumlein transmission line with a load which are pure resistivity or have distributed parameter. The results are about the same as that of the travel wave method..
Termination match is a key for the design of transmission line. This paper, using Laplace transform method, describes exactly the transient transmission process of a Blumlein transmission line with a load which are pure resistivity or have distributed parameter. The results are about the same as that of the travel wave method..
2000,
12.
Abstract:
In order to broaden the application of Hefei synchrotron radiation Light Source (HLS), and meet the request of Synchrotron Radiation (SR) pulses with long interval for some special experiments. We study using vertical local bump orbit to adjust the interval of SR pulses. Physical calculation and computer simulation have been done with 3 different lattice configurations, the effects of bump magnets on storage ring are also analyzed in the paper.
In order to broaden the application of Hefei synchrotron radiation Light Source (HLS), and meet the request of Synchrotron Radiation (SR) pulses with long interval for some special experiments. We study using vertical local bump orbit to adjust the interval of SR pulses. Physical calculation and computer simulation have been done with 3 different lattice configurations, the effects of bump magnets on storage ring are also analyzed in the paper.
2000,
12.
Abstract:
The paper analyzes and measures the influence of the stray fields on DCCT system for Hefei Light Source(HLS). The design of the magnetic shielding of DCCT system is presented. The computed and measured results of shielding factor are given. The magnetic shielding against stray fields suppressed zero drifts of DCCT from 1mA to 10m A.
The paper analyzes and measures the influence of the stray fields on DCCT system for Hefei Light Source(HLS). The design of the magnetic shielding of DCCT system is presented. The computed and measured results of shielding factor are given. The magnetic shielding against stray fields suppressed zero drifts of DCCT from 1mA to 10m A.
2000,
12.
Abstract:
The longitudinal weakfield for the two counter-rotating beams is studied in this paper. It is conclude that the shunt impedance seen by the counter-moving particle is in general complex. One formula for two-beam's longitudinal coupled bunch instability is developed and the character of two-beam instabilities is presented.
The longitudinal weakfield for the two counter-rotating beams is studied in this paper. It is conclude that the shunt impedance seen by the counter-moving particle is in general complex. One formula for two-beam's longitudinal coupled bunch instability is developed and the character of two-beam instabilities is presented.
2000,
12.
Abstract:
The plasma closure images of two-dimensional space and one-dimensional time for 1.053m m slanting incidence laser were observed successfully for the first time at the“XingguangII”facility with an X-ray twelve-frame camera. The plasma closure velocities under the condition of laser slanting incidence have been obtained separately by experiment and one-dimensional model. The experimental results show that under the same conditions the plasma expanding speed is 15% higher for half-cavity targets than that for hole targets.
The plasma closure images of two-dimensional space and one-dimensional time for 1.053m m slanting incidence laser were observed successfully for the first time at the“XingguangII”facility with an X-ray twelve-frame camera. The plasma closure velocities under the condition of laser slanting incidence have been obtained separately by experiment and one-dimensional model. The experimental results show that under the same conditions the plasma expanding speed is 15% higher for half-cavity targets than that for hole targets.
2000,
12.
Abstract:
Time-integrated spectra of second harmonic (2w ) light emission from plasmas produced with 1.053m m laser are simultaneously measured at several scattering-angles on Xingguang II laser facility. The spectra show that 2w light is just due to resonance absorption, and ion-acoustic decay instability is suppressed. The mean velocity of critical surface and its variation during laser pulse are inferred from the spectra. Moreover, the relationship between scattered light intensity and scattering angle is also acquired.
Time-integrated spectra of second harmonic (2w ) light emission from plasmas produced with 1.053m m laser are simultaneously measured at several scattering-angles on Xingguang II laser facility. The spectra show that 2w light is just due to resonance absorption, and ion-acoustic decay instability is suppressed. The mean velocity of critical surface and its variation during laser pulse are inferred from the spectra. Moreover, the relationship between scattered light intensity and scattering angle is also acquired.
2000,
12.
Abstract:
X-ray diodes(XRDs) have been calibrated on BEPC synchrotron radiation device. A simple model was used to describe the photoelectric emission of XRD photocathodes. Surface smoothness, oxygen and carbon contaminants were enough to explain deviations of calibrated sensitivities from the model's predictions for metal photocathodes.
X-ray diodes(XRDs) have been calibrated on BEPC synchrotron radiation device. A simple model was used to describe the photoelectric emission of XRD photocathodes. Surface smoothness, oxygen and carbon contaminants were enough to explain deviations of calibrated sensitivities from the model's predictions for metal photocathodes.
2000,
12.
Abstract:
Intense X-ray radiation,beening used as X-ray source, has been produced from the rear of gold foil by interaction of 0.35m m laser with gold-plasma on Xingguang laser facility.Time evolution of X-ray radiation from both the X-ray source region and self-emission region of the radiation-ablated aluminium sample has been recorded by a space-resolved X-ray streak camera.
Intense X-ray radiation,beening used as X-ray source, has been produced from the rear of gold foil by interaction of 0.35m m laser with gold-plasma on Xingguang laser facility.Time evolution of X-ray radiation from both the X-ray source region and self-emission region of the radiation-ablated aluminium sample has been recorded by a space-resolved X-ray streak camera.
2000,
12.
Abstract:
Interfacial polycondensatin Technique has been used to prepare PS-PVA double-layered hollow microshells in this paper. The factors such as the concentration of isophthaloyl chloride, reaction time, stir velocity and drying temperature which influence the process have been discussion.
Interfacial polycondensatin Technique has been used to prepare PS-PVA double-layered hollow microshells in this paper. The factors such as the concentration of isophthaloyl chloride, reaction time, stir velocity and drying temperature which influence the process have been discussion.
2000,
12.
Abstract:
A compact hydrogen plasma gun system was designed and tested. There are two rings of graphite and two rings of Ti hydride between coaxial electrodes. Ti hydride is utilized as a reservoir of hydrogen. The surface flashover is taken advantage to produce plasma. The produced plasma density is 1010cm-3~ 1012cm-3 in a volume of a column with radius 1cm~2cm and length of 60cm~80cm. The plasma existing time is over 400m s. The plasma gun system is simple, light-weight and compact. It is suitable for high power microwave tubes.
A compact hydrogen plasma gun system was designed and tested. There are two rings of graphite and two rings of Ti hydride between coaxial electrodes. Ti hydride is utilized as a reservoir of hydrogen. The surface flashover is taken advantage to produce plasma. The produced plasma density is 1010cm-3~ 1012cm-3 in a volume of a column with radius 1cm~2cm and length of 60cm~80cm. The plasma existing time is over 400m s. The plasma gun system is simple, light-weight and compact. It is suitable for high power microwave tubes.
2000,
12.
Abstract:
Moiré deflection measurement can be used to calculate refractive index by measuring deflection of probe beam passing through mediums. A moiré deflectometer is designed, which can measure electron density spatial distribution of high-temperature high-density plasma using soft X-ray laser as probe, and a basal demonstration is given.
Moiré deflection measurement can be used to calculate refractive index by measuring deflection of probe beam passing through mediums. A moiré deflectometer is designed, which can measure electron density spatial distribution of high-temperature high-density plasma using soft X-ray laser as probe, and a basal demonstration is given.
2000,
12.
Abstract:
Based on the theory of the ellipsoidal grating, the idea of cylindrical concave grating is put forward in this paper, the diffracting properties and collecting light ability of cylindrical concave grating are studied. The results show that the diffracting properties of cylindrical concave grating and spherical concave grating are similar under the condition of grazing incidence, but the cylindrical concave grating may be divided into certain congruent sectors along the direction of the grating generator for independent operation. Therefore, the grazing incidence cylindrical grating monochromator for mounting horizontal baffle plates may be used for the space-time resolving measurement of vacuum ultraviolet (VUV) spectrum of Tokamak plasma.
Based on the theory of the ellipsoidal grating, the idea of cylindrical concave grating is put forward in this paper, the diffracting properties and collecting light ability of cylindrical concave grating are studied. The results show that the diffracting properties of cylindrical concave grating and spherical concave grating are similar under the condition of grazing incidence, but the cylindrical concave grating may be divided into certain congruent sectors along the direction of the grating generator for independent operation. Therefore, the grazing incidence cylindrical grating monochromator for mounting horizontal baffle plates may be used for the space-time resolving measurement of vacuum ultraviolet (VUV) spectrum of Tokamak plasma.
2000,
12.
Abstract:
This article briefly described the measurement of electron temperature in Tokamak plasma. It described the reasons of blue shift because of relativity and the way of relativistic modification in case of higher electron temperature. Then it gave the spatial distribution of electron temperature of two shots on HT-7 Tokamak, one is under the condition that blue shift is taken into account, the other is under the condition that blue shift is not taken into account.
This article briefly described the measurement of electron temperature in Tokamak plasma. It described the reasons of blue shift because of relativity and the way of relativistic modification in case of higher electron temperature. Then it gave the spatial distribution of electron temperature of two shots on HT-7 Tokamak, one is under the condition that blue shift is taken into account, the other is under the condition that blue shift is not taken into account.
2000,
12.
Abstract:
The residual phase variance for tip-tilt correction adaptive optical system is analyzed by considering the modal coupling. The modal coupling coefficient, is introduced to analyze the effect of the modal coupling on the anisoplanatism limitation of the tip-tilt correction adaptive optical system. Furthermore, the numerical results for the light beam horizontal atmospheric propagation are presented.
The residual phase variance for tip-tilt correction adaptive optical system is analyzed by considering the modal coupling. The modal coupling coefficient, is introduced to analyze the effect of the modal coupling on the anisoplanatism limitation of the tip-tilt correction adaptive optical system. Furthermore, the numerical results for the light beam horizontal atmospheric propagation are presented.
2000,
12.
Abstract:
This paper describes the conception and the applications of the power spectral density function in optical surface profile measurement. It includes power spectral density (PSD standard in ISO10110-8 and its origin, the connection between the light intensity disturbing and PSD function from the surface figure and surface finish. At last the PSD function of the high power laser optical elements is discussed.
This paper describes the conception and the applications of the power spectral density function in optical surface profile measurement. It includes power spectral density (PSD standard in ISO10110-8 and its origin, the connection between the light intensity disturbing and PSD function from the surface figure and surface finish. At last the PSD function of the high power laser optical elements is discussed.
2000,
12.
Abstract:
Based on the generalized Huygens-Fresnel diffraction integral and in consideration of the effect introduced by astigmatism, the transformation properties of Gaussian beams passing an astigmatic lens are studied analytically, the beam quality of astigmatic Gaussian beams is analyzed in terms of the beam propagation factor(M2-factor) and power in the bucket(PIB), and illustrated with numerical examples.
Based on the generalized Huygens-Fresnel diffraction integral and in consideration of the effect introduced by astigmatism, the transformation properties of Gaussian beams passing an astigmatic lens are studied analytically, the beam quality of astigmatic Gaussian beams is analyzed in terms of the beam propagation factor(M2-factor) and power in the bucket(PIB), and illustrated with numerical examples.
2000,
12.
Abstract:
Three types of state-to-state dielectronic recombination processes for Be-like ions Ti18+ have been investigated. Based on multi-configuration Hartree-Fock-Relativistic and distorted wave approaches, state-to-state dielectronic recombination rate coefficients have calculated at electron temperature 0.01~1.0keV, Variations of the coefficients with electron temperatures, recombination types and up-or down-states have also been discussed in detial.
Three types of state-to-state dielectronic recombination processes for Be-like ions Ti18+ have been investigated. Based on multi-configuration Hartree-Fock-Relativistic and distorted wave approaches, state-to-state dielectronic recombination rate coefficients have calculated at electron temperature 0.01~1.0keV, Variations of the coefficients with electron temperatures, recombination types and up-or down-states have also been discussed in detial.
2000,
12.
Abstract:
We have investigated numerically the thermal recovery of the large aperture multi0segment amplifiers in the paper. With AMPHR3D, which is a thre-dimensional transient finite element heat transfer code, the temperature of Na:glass slab is investigated in detial, Preliminary thermal analysis indicates that active cooling with 4.7 10- 3m3s- 1 per flash lamp in lamp cassette cooperated with 7.6 10- 3m3s- 1 per slab cavity is sufficient to meet the 4 hour shot period of the lser system.
We have investigated numerically the thermal recovery of the large aperture multi0segment amplifiers in the paper. With AMPHR3D, which is a thre-dimensional transient finite element heat transfer code, the temperature of Na:glass slab is investigated in detial, Preliminary thermal analysis indicates that active cooling with 4.7 10- 3m3s- 1 per flash lamp in lamp cassette cooperated with 7.6 10- 3m3s- 1 per slab cavity is sufficient to meet the 4 hour shot period of the lser system.
2000,
12.
Abstract:
This paper reviews that the various reported laser-induced effects on the photoelectric detectors and their composed material．It collects all kinds of thresholds of shape damage and electricity damage systematically, and analyzes these cases contrastively．Ａt the same time several kinds of the laser-induced damage mechanism and their theoretical models are discussed.
This paper reviews that the various reported laser-induced effects on the photoelectric detectors and their composed material．It collects all kinds of thresholds of shape damage and electricity damage systematically, and analyzes these cases contrastively．Ａt the same time several kinds of the laser-induced damage mechanism and their theoretical models are discussed.
2000,
12.
Abstract:
Mode calculation in unstable resonators with flowing saturable gain using the fast fourier trans-form(FFT) algorithm and more gain segments method in resonator. This method had more wide-ranging applied .
Mode calculation in unstable resonators with flowing saturable gain using the fast fourier trans-form(FFT) algorithm and more gain segments method in resonator. This method had more wide-ranging applied .
2000,
12.
Abstract:
The combination of CPA technique with the existing high-power solid-state laser facilities for fusion application has created a new generation of lasers. Pulse durations are decreased by three to four orders of magnitude and peak powers are increased by two to three orders of magnitude reaching 100TW and even over 1PW, resulting in enormous intensities of 1021W/cm2. The breakthrough of laser technology has opened an amazing world of physics research. Unexpected phenomena have been observed and possible applications are being explored.
The combination of CPA technique with the existing high-power solid-state laser facilities for fusion application has created a new generation of lasers. Pulse durations are decreased by three to four orders of magnitude and peak powers are increased by two to three orders of magnitude reaching 100TW and even over 1PW, resulting in enormous intensities of 1021W/cm2. The breakthrough of laser technology has opened an amazing world of physics research. Unexpected phenomena have been observed and possible applications are being explored.
2000,
12.
Abstract:
We obtained the dielectronic- recombination rate coefficients of Ni-like Au51+ through Cu-like 3d9nln'l'(n'=4,5,6; l'=s,p,d,f) in the range of 0.02keV ~ 10keV under the model of SOSA(spin-orbit-split Array).At the same time ,we analyzed the main factor which effected the dielectronic recombination rate coefficients with the electronic temperature.
We obtained the dielectronic- recombination rate coefficients of Ni-like Au51+ through Cu-like 3d9nln'l'(n'=4,5,6; l'=s,p,d,f) in the range of 0.02keV ~ 10keV under the model of SOSA(spin-orbit-split Array).At the same time ,we analyzed the main factor which effected the dielectronic recombination rate coefficients with the electronic temperature.
2000,
12.
Abstract:
The Einstein coefficients and line-emission intensities of Au ions are calculated with an improved More model. The population of the ions and the X-ray emission spectrum are given by solving stationary H-like ion-model rate-equations for the corona plasma produced by coupling of laser with Au target. The spectrum is compared with the photon that obtained by multi-group photon diffusion code JB19 simulation.
The Einstein coefficients and line-emission intensities of Au ions are calculated with an improved More model. The population of the ions and the X-ray emission spectrum are given by solving stationary H-like ion-model rate-equations for the corona plasma produced by coupling of laser with Au target. The spectrum is compared with the photon that obtained by multi-group photon diffusion code JB19 simulation.
2000,
12.
Abstract:
The results of antireflection thin film systems for signle crystal CaF2 and silicon windows for application at DF laser wavelengths have been present in this paper. The method designing multilayer AR cating structure has been anlyzed, and ZnS/YbF3 combination. The theoretical performances evaluated for various coating. The deposition process has CaF2 and silicon windows obtained. The damage threshold is more than 4.3kW/cm2 at continue wave DF laser wavelength region for AR coated CaF2 windows.
The results of antireflection thin film systems for signle crystal CaF2 and silicon windows for application at DF laser wavelengths have been present in this paper. The method designing multilayer AR cating structure has been anlyzed, and ZnS/YbF3 combination. The theoretical performances evaluated for various coating. The deposition process has CaF2 and silicon windows obtained. The damage threshold is more than 4.3kW/cm2 at continue wave DF laser wavelength region for AR coated CaF2 windows.
2000,
12.
Abstract:
The combustion-chamber’s composition、small-signal gain distribution along flow direction and laser’s power and specific power of the combustion-driven gas-dynamic CO2 laser with toluene、benzene、kerosene and alcohol separately combustion driven were numerically simulated. The four different conditions were compared and the results will be referential to CO2 laser’s study. The results indicated toluene is an optimum fuel of the four gas-dynamic CO2 laser’s fuels.
The combustion-chamber’s composition、small-signal gain distribution along flow direction and laser’s power and specific power of the combustion-driven gas-dynamic CO2 laser with toluene、benzene、kerosene and alcohol separately combustion driven were numerically simulated. The four different conditions were compared and the results will be referential to CO2 laser’s study. The results indicated toluene is an optimum fuel of the four gas-dynamic CO2 laser’s fuels.
2000,
12.
Abstract:
Performance properties of a frequency doubled harmonic gyro-twt amplifier is studied in this paper. Numerical simulation show that using a 130kV, 20A electron beam with a velocity ratio of 0.8 and an axial velocity spread of 1%, a saturated bandwidth of 10% can be obtained in an uniform waveguide, the peak output power, gain and efficiency are, respectively, 290kW, 50dB and 11%.
Performance properties of a frequency doubled harmonic gyro-twt amplifier is studied in this paper. Numerical simulation show that using a 130kV, 20A electron beam with a velocity ratio of 0.8 and an axial velocity spread of 1%, a saturated bandwidth of 10% can be obtained in an uniform waveguide, the peak output power, gain and efficiency are, respectively, 290kW, 50dB and 11%.
2000,
12.
Abstract:
From the foundational theory of explosive magnetic flux compression generator (MFCG), the inductance, resistance and current of non-symmetrical multi-branch helical MFCG have been calculated. And discussed the operation character of high inductance MFCG with low inductance load. An effective way of obtaining high energy gain of MFCG is to increase the ratio of its initial inductance to load inductance by increasing the initial one. It can provide a better voltage flat increasing number of helical coil sections and wires in parallel.
From the foundational theory of explosive magnetic flux compression generator (MFCG), the inductance, resistance and current of non-symmetrical multi-branch helical MFCG have been calculated. And discussed the operation character of high inductance MFCG with low inductance load. An effective way of obtaining high energy gain of MFCG is to increase the ratio of its initial inductance to load inductance by increasing the initial one. It can provide a better voltage flat increasing number of helical coil sections and wires in parallel.
2000,
12.
Abstract:
Experimental research on short-pulse high power microwave (HPM) air breakdown in waveguide and free space is described. Breakdown thresholds for a range of air pressure are presented. Experiment research on HPM air breakdown in waveguide is proved to be a reasonable method through the comparison of two kinds of experiment data, each kind of which is consistent with another very well.
Experimental research on short-pulse high power microwave (HPM) air breakdown in waveguide and free space is described. Breakdown thresholds for a range of air pressure are presented. Experiment research on HPM air breakdown in waveguide is proved to be a reasonable method through the comparison of two kinds of experiment data, each kind of which is consistent with another very well.
2000,
12.
Abstract:
Starting from homogeneous scalar Helmholtz’s equations associated with Borgnis potential function in a cylindrical coordinate system, and based on the standing wave concept of slow-wave introduced in the paper, the analytic expressions of the dispersion relation and field distribution for azimuthally symmetric transverse magnetic modes in the three-cavity Transit-time Tube oscillator are derived, by using boundary conditions for Borgnis potential function in conjunction with field matching conditions at the common interface between the adjacent subregions. The resonance frequency of the oscillator calculated by this analytic method is compared with that measured in experiments and it is found that they are in agreement quite well. The field distribution of the oscillator developed by this
Starting from homogeneous scalar Helmholtz’s equations associated with Borgnis potential function in a cylindrical coordinate system, and based on the standing wave concept of slow-wave introduced in the paper, the analytic expressions of the dispersion relation and field distribution for azimuthally symmetric transverse magnetic modes in the three-cavity Transit-time Tube oscillator are derived, by using boundary conditions for Borgnis potential function in conjunction with field matching conditions at the common interface between the adjacent subregions. The resonance frequency of the oscillator calculated by this analytic method is compared with that measured in experiments and it is found that they are in agreement quite well. The field distribution of the oscillator developed by this
2000,
12.
Abstract:
An optical pump source is constructed on the basis of a sectioned low voltage surface discharge in the form of strictly linear plasma channels with a total working length of 42 cm . A distributed-transmission-line model on the distribution of the electric field along the surface of the radiation source is developed. The effect from the trigger pulse and the specific capacitance of the dielectric substrate is analyzed and a small time scatter of operation from the individual sections (<100ns) is obtained in experiment.
An optical pump source is constructed on the basis of a sectioned low voltage surface discharge in the form of strictly linear plasma channels with a total working length of 42 cm . A distributed-transmission-line model on the distribution of the electric field along the surface of the radiation source is developed. The effect from the trigger pulse and the specific capacitance of the dielectric substrate is analyzed and a small time scatter of operation from the individual sections (<100ns) is obtained in experiment.
2000,
12.
Abstract:
A semiempirical model of electro-explosive fuse opening switches (EFOS) based on the dependence of fuse resistance increase on specific energy is developed. The switch model coupled with the inductive energy storage system(IESS) is integrated into PSPICE circuit simulation code. The calculations of EFOS output pulses are in agreement with the experimental results . The relationship between the load resistance and output pulse is also discussed by means of the circuit simulation.
A semiempirical model of electro-explosive fuse opening switches (EFOS) based on the dependence of fuse resistance increase on specific energy is developed. The switch model coupled with the inductive energy storage system(IESS) is integrated into PSPICE circuit simulation code. The calculations of EFOS output pulses are in agreement with the experimental results . The relationship between the load resistance and output pulse is also discussed by means of the circuit simulation.
2000,
12.
Abstract:
A kind of analysis method used for computing the singly reentrant cylindrical cavity of relativistic klystron is developed in this paper. According to equivalent principle of field the cavity is divided into three regular regions. The field in each region is supported by proper surface magnetic current density on the common surface and can be expressed as integral of Green functions. The magnetic fields of two neighboring regions are then matched on the common surface to obtain a set of integral equations.
A kind of analysis method used for computing the singly reentrant cylindrical cavity of relativistic klystron is developed in this paper. According to equivalent principle of field the cavity is divided into three regular regions. The field in each region is supported by proper surface magnetic current density on the common surface and can be expressed as integral of Green functions. The magnetic fields of two neighboring regions are then matched on the common surface to obtain a set of integral equations.
2000,
12.
Abstract:
The principle and the parameters of the high voltage pulse generator which has been used in the“Spring-thunder”bounded-wave EMP simulator are described in this paper. The measured and calculated waveform are also presented. A double-exponential waveform with about 10ns risetime, and 300ns pulsewidth can be produced by this pulse generator.
The principle and the parameters of the high voltage pulse generator which has been used in the“Spring-thunder”bounded-wave EMP simulator are described in this paper. The measured and calculated waveform are also presented. A double-exponential waveform with about 10ns risetime, and 300ns pulsewidth can be produced by this pulse generator.
