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RSS1996 Vol. 08, No. 03
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1996,
08.
Abstract:
The absorption distributions for quarter wavelength coating stacks and enhanced metal –dielectric laser reflect coatings are analyzed in this paper. The thermal distortions of optical components subjected to CW DF high power laser irradiation are computed and measured. The calculated data is compared with the experimental results.
The absorption distributions for quarter wavelength coating stacks and enhanced metal –dielectric laser reflect coatings are analyzed in this paper. The thermal distortions of optical components subjected to CW DF high power laser irradiation are computed and measured. The calculated data is compared with the experimental results.
1996,
08.
Abstract:
Nonadaptive coordinate transformations are applied to the basic equations for the simulation of thermal blooming of focused high –power beams propagation through the atmosphere in the report. The results show that the accuracy and speed of the computation can be improved efficiently. But it is difficult to calculate the field near the focal plane because of the defocusing of the thermal blooming. A modified nonadaptive changes are presented in the paper which overcome the disadvantage of the old nonadaptive changes, and has proved to be more efficient in the improvement of accuracy and speed of computation, and reduction of computer’s memory.
Nonadaptive coordinate transformations are applied to the basic equations for the simulation of thermal blooming of focused high –power beams propagation through the atmosphere in the report. The results show that the accuracy and speed of the computation can be improved efficiently. But it is difficult to calculate the field near the focal plane because of the defocusing of the thermal blooming. A modified nonadaptive changes are presented in the paper which overcome the disadvantage of the old nonadaptive changes, and has proved to be more efficient in the improvement of accuracy and speed of computation, and reduction of computer’s memory.
1996,
08.
Abstract:
Repetitively Pulsed YAG laser heating 30CrMnSiA steel which are placed in natural heat connective environment and forced heat connective environment is studied from experiments. The experiment results show that tangential airflow (about 0.1Ma) obviously increases laser energy or power needed by material pocessing, which is in accord with results from aerodynamic theory.
Repetitively Pulsed YAG laser heating 30CrMnSiA steel which are placed in natural heat connective environment and forced heat connective environment is studied from experiments. The experiment results show that tangential airflow (about 0.1Ma) obviously increases laser energy or power needed by material pocessing, which is in accord with results from aerodynamic theory.
1996,
08.
Abstract:
A FIR –FEL resonator with wavelength 500m m is studied, which has a semi –closed optical cavity composed of a plane waveguide and two symmetric cylindrical metal mirrors. There is a hole of radius Rh on axis in the down –stream mirror. Some three-dimensional numerical results are given, which provide the interactive power, the output power, the extraction ratios and the diffraction loses on the mirror edge for various hole radius. If chewing an appropriate hole, so interactive power and good cavity modes can be obtained, and outputting the power very effectively.
A FIR –FEL resonator with wavelength 500m m is studied, which has a semi –closed optical cavity composed of a plane waveguide and two symmetric cylindrical metal mirrors. There is a hole of radius Rh on axis in the down –stream mirror. Some three-dimensional numerical results are given, which provide the interactive power, the output power, the extraction ratios and the diffraction loses on the mirror edge for various hole radius. If chewing an appropriate hole, so interactive power and good cavity modes can be obtained, and outputting the power very effectively.
1996,
08.
Abstract:
The emission from blue Kr2F excimer laser centered at 415nm has been achieved in e –beam –pumped Ar/Kr/F2 mixture. The laser energy is up to 2mJ at p=0.3MPa. The spectral bandwidth is 15nm and laser divergent angle is 5mrad. For first time the multi –split laser spectrum line are observed at near 370nm.
The emission from blue Kr2F excimer laser centered at 415nm has been achieved in e –beam –pumped Ar/Kr/F2 mixture. The laser energy is up to 2mJ at p=0.3MPa. The spectral bandwidth is 15nm and laser divergent angle is 5mrad. For first time the multi –split laser spectrum line are observed at near 370nm.
1996,
08.
Abstract:
In this paper, the physics of optical klystron, which including the beam energy modulation, the beam density modulation and the harmonic super radiation are simulated.
In this paper, the physics of optical klystron, which including the beam energy modulation, the beam density modulation and the harmonic super radiation are simulated.
1996,
08.
Abstract:
The research progress of superconducting cavity made in Chinese Niobium are introduced with the emphasis on the quality improvement of the Niobium and corresponding superconducting cavity. The designing of the cavity geometry, analyzing of the RF property of the Niobium as well as its mechanical quality are described. Special procedure of the cavity fabricating and its post processing are set. Experimentally, the gradient of 10MV/m and quality factor of 109 at 2.5K are given.
The research progress of superconducting cavity made in Chinese Niobium are introduced with the emphasis on the quality improvement of the Niobium and corresponding superconducting cavity. The designing of the cavity geometry, analyzing of the RF property of the Niobium as well as its mechanical quality are described. Special procedure of the cavity fabricating and its post processing are set. Experimentally, the gradient of 10MV/m and quality factor of 109 at 2.5K are given.
1996,
08.
Abstract:
The key points in cell design of Linear Induction Accelerator are presented. The equations of the accelerating voltage and its flattop versus parameters of the cell are given. The measures taken to reduce the transverse coupling impedance of the cell are described. Two prototype cells are also presented as a practice of the idea on cell design.
The key points in cell design of Linear Induction Accelerator are presented. The equations of the accelerating voltage and its flattop versus parameters of the cell are given. The measures taken to reduce the transverse coupling impedance of the cell are described. Two prototype cells are also presented as a practice of the idea on cell design.
1996,
08.
Abstract:
The sensitivity calibration of UFsh –O X ray film on the X ray source excited by protons are described in this paper. The sensitivity curves of UFsh –O X ray film at eight energy point are obtained.
The sensitivity calibration of UFsh –O X ray film on the X ray source excited by protons are described in this paper. The sensitivity curves of UFsh –O X ray film at eight energy point are obtained.
1996,
08.
Abstract:
A 100J level KrF laser pumped by an intense relativistic electron beam –Flash II has been developed successfully. The main structure and specifications of the laser are reported in this paper. The maximum laser output energy of 157J with a parallel resonator at the diode voltage of 840kV and current of 200kA are obtained. The peak power is measured to be more than 2.0GW. The dependence of laser output energy with Kr and F2 concentration are also studied.
A 100J level KrF laser pumped by an intense relativistic electron beam –Flash II has been developed successfully. The main structure and specifications of the laser are reported in this paper. The maximum laser output energy of 157J with a parallel resonator at the diode voltage of 840kV and current of 200kA are obtained. The peak power is measured to be more than 2.0GW. The dependence of laser output energy with Kr and F2 concentration are also studied.
1996,
08.
Abstract:
Using numerical simulation, the fitting error is calculated in the adaptive optics phase compensation for turbulent effect of laser propagation in the atmosphere. The results show that the fitting error of the adaptive optics system is 1.24 times of that calculated using the least –squares –fit method.
Using numerical simulation, the fitting error is calculated in the adaptive optics phase compensation for turbulent effect of laser propagation in the atmosphere. The results show that the fitting error of the adaptive optics system is 1.24 times of that calculated using the least –squares –fit method.
1996,
08.
Abstract:
With an INEX model, the start up and the structure of optical pulse of CAEP FIR FEL are studied. To counteract the effect of lethargy, the necessary detaining of the cavity length, and precision and range for adjusting cavity length are given. The gain, power, pulse width and bandwidth are predicted. The pulse structure different cavity length is investigated.
With an INEX model, the start up and the structure of optical pulse of CAEP FIR FEL are studied. To counteract the effect of lethargy, the necessary detaining of the cavity length, and precision and range for adjusting cavity length are given. The gain, power, pulse width and bandwidth are predicted. The pulse structure different cavity length is investigated.
1996,
08.
Abstract:
Coupling La –doped BaF2 crystal to phototube is an effective way to prevent signal pileup in ultra –fast radiation detector under strong g field. The ratios of slow components to fast ones of domestic BaF2 crystal and La –doped BaF2 crystal have been investigated through Synchrotron Radiation Decay Time Spectroscopy and X ray Excited Emission Spectroscopy. The mechanism of the slow component suppression by doping with La and the anti-irradiation property of BaF2（La）are studied. The slow component suppression of ultra –fast radiation detector, which was composed of BaF2（La）and GD40Z phototube is measured through Synchrotron Radiation.
Coupling La –doped BaF2 crystal to phototube is an effective way to prevent signal pileup in ultra –fast radiation detector under strong g field. The ratios of slow components to fast ones of domestic BaF2 crystal and La –doped BaF2 crystal have been investigated through Synchrotron Radiation Decay Time Spectroscopy and X ray Excited Emission Spectroscopy. The mechanism of the slow component suppression by doping with La and the anti-irradiation property of BaF2（La）are studied. The slow component suppression of ultra –fast radiation detector, which was composed of BaF2（La）and GD40Z phototube is measured through Synchrotron Radiation.
1996,
08.
Abstract:
Two radiating systems for generating a scanning high power microwave beam are presented. The first one uses beamwaveguide to feed an offset paraboloid antenna, which is suited for overmode input waveguide. The second consists of an offset paraboloid antenna fed by a multimode horn that is linked to a vacuum flexiable elliptical waveguide as a method of limited elevation scan, which is simple and suited for the transmitter with single mode output waveguide. The physical optics analysis technique is used to investigate above antennas. The numerical results shows that the gains and spillover efficiencies are reasonable.
Two radiating systems for generating a scanning high power microwave beam are presented. The first one uses beamwaveguide to feed an offset paraboloid antenna, which is suited for overmode input waveguide. The second consists of an offset paraboloid antenna fed by a multimode horn that is linked to a vacuum flexiable elliptical waveguide as a method of limited elevation scan, which is simple and suited for the transmitter with single mode output waveguide. The physical optics analysis technique is used to investigate above antennas. The numerical results shows that the gains and spillover efficiencies are reasonable.
1996,
08.
Abstract:
In this paper, electron backbom and the beam qualities of the RF –gun in the real conditions is investigated by means of particles simulations. The influences of the cavity length and amplitude of electric field are presented. And the methodes decreasing the power of backbom are discussed.
In this paper, electron backbom and the beam qualities of the RF –gun in the real conditions is investigated by means of particles simulations. The influences of the cavity length and amplitude of electric field are presented. And the methodes decreasing the power of backbom are discussed.
1996,
08.
Abstract:
A comparison between using coronal zone and conduction zone to produce gain in recombination X ray laser is made and the characteristics of coronal plasma in the expanding recombined phase are discussed. The optimum laser energy absorbed and the mass of the coronal zone is estimated when it is used to produce gain.
A comparison between using coronal zone and conduction zone to produce gain in recombination X ray laser is made and the characteristics of coronal plasma in the expanding recombined phase are discussed. The optimum laser energy absorbed and the mass of the coronal zone is estimated when it is used to produce gain.
1996,
08.
Abstract:
Based on the HFR method and considering configuration interaction between bound states, some problems and inadequacies what may be are discussed, and corrected method is given to solve these problems. Using the method, photoionization cross sections of Li, Na and Cs atoms are calculated and compared with references. The difference and relationship between the orbital –orbital and the summed level –level photoionization cross sections are discussed and analysed theoretically.
Based on the HFR method and considering configuration interaction between bound states, some problems and inadequacies what may be are discussed, and corrected method is given to solve these problems. Using the method, photoionization cross sections of Li, Na and Cs atoms are calculated and compared with references. The difference and relationship between the orbital –orbital and the summed level –level photoionization cross sections are discussed and analysed theoretically.
1996,
08.
Abstract:
The structure and the measuring arrangements of vircator with a large plane velvet cathode diode to induce long pulsed microwave radiation are given. The cathode –anode plasma closed velosity, the maximum pulsewidth of the microwave radiation, the microwave peak power and frequence are measured. It is shown that there exists physically restriction in this kind of flat diode vircator between radiation pulse width, radiation frequence and radiation power. It is pointed too that coaxial vircator will be a new way to get rid of such a restriction.
The structure and the measuring arrangements of vircator with a large plane velvet cathode diode to induce long pulsed microwave radiation are given. The cathode –anode plasma closed velosity, the maximum pulsewidth of the microwave radiation, the microwave peak power and frequence are measured. It is shown that there exists physically restriction in this kind of flat diode vircator between radiation pulse width, radiation frequence and radiation power. It is pointed too that coaxial vircator will be a new way to get rid of such a restriction.
1996,
08.
Abstract:
Numerical simulations of CAEP FIR FEL are made with a INEX (Integrated Numerical Experiment) model in which the transverse distribution is considered carefully. Compared with the results of simulations with Moute Carlo method, large differences between them are found. The performance of free electron lasers depends upon the characteristics of the electron beam. It is necessary to use this kind of INEX simulations in order to accurately calculated and predict the lasing performance of free electron lasers.
Numerical simulations of CAEP FIR FEL are made with a INEX (Integrated Numerical Experiment) model in which the transverse distribution is considered carefully. Compared with the results of simulations with Moute Carlo method, large differences between them are found. The performance of free electron lasers depends upon the characteristics of the electron beam. It is necessary to use this kind of INEX simulations in order to accurately calculated and predict the lasing performance of free electron lasers.
1996,
08.
Abstract:
The experiments are carried out at “Shengguang” laser facility with two special targets. The X ray radiation symmetry in hohlraum targets is investigated by observing the X ray spectra and radiation energy in different aspects. A brief discussion about the measurements is performed.
The experiments are carried out at “Shengguang” laser facility with two special targets. The X ray radiation symmetry in hohlraum targets is investigated by observing the X ray spectra and radiation energy in different aspects. A brief discussion about the measurements is performed.
1996,
08.
Abstract:
In this paper, the effects of the geometrical configuration prameters, including the cathode radius Rc, the anode –cathode gap dA-K, the anode aperture radius Ra and the cathode traverse length L, on the electron beams on foilless diode are studied using a numerical simulation method. The basic criterion of the selection of parameters such as dA-K≥3Rc, 1.7≤Ra/Rc≤1.8, and L/Rc=2 ~3 is obtained. In this condition, the high –brightness electron beam can be easily generated. The optimization of parameters of foilless diode model according to the realistic circumstances is given.
In this paper, the effects of the geometrical configuration prameters, including the cathode radius Rc, the anode –cathode gap dA-K, the anode aperture radius Ra and the cathode traverse length L, on the electron beams on foilless diode are studied using a numerical simulation method. The basic criterion of the selection of parameters such as dA-K≥3Rc, 1.7≤Ra/Rc≤1.8, and L/Rc=2 ~3 is obtained. In this condition, the high –brightness electron beam can be easily generated. The optimization of parameters of foilless diode model according to the realistic circumstances is given.
1996,
08.
Abstract:
The numerical simulations of high voltage pulsed power conditioning system (inductive storage /opening switches) are given in this paper. According the different initial energy, the capacitor model and simple MFCG model are computed. For the second model, two cases –not carrying opening switches load and carrying opening switches load are considered, the results show that the current will change 20% ~31%. In the capacitor model, the affection of load, initial charging voltage, inductive storage et al are considered. By using the numerical results that only the running parameters in the system are optimized, some effective output results can be got possible.
The numerical simulations of high voltage pulsed power conditioning system (inductive storage /opening switches) are given in this paper. According the different initial energy, the capacitor model and simple MFCG model are computed. For the second model, two cases –not carrying opening switches load and carrying opening switches load are considered, the results show that the current will change 20% ~31%. In the capacitor model, the affection of load, initial charging voltage, inductive storage et al are considered. By using the numerical results that only the running parameters in the system are optimized, some effective output results can be got possible.
1996,
08.
Abstract:
With the atomic parameters calculated by ourselves, the angular distribution, space distribution and transformation efficiency for hard X ray, are calculated which are generated by the interaction between hot electrons and cold wall of the cavity in ICF experiments. This provides a basis for the experimental investigation of hot electrons inside cavity target.
With the atomic parameters calculated by ourselves, the angular distribution, space distribution and transformation efficiency for hard X ray, are calculated which are generated by the interaction between hot electrons and cold wall of the cavity in ICF experiments. This provides a basis for the experimental investigation of hot electrons inside cavity target.
1996,
08.
Abstract:
In adaptive optics system, the effectiveness of wavefront correction is influenced gy the types of wavefront sensor and corrector, their relative configuration (matching) and wavefront reconstruction algorithm. In this paper, the computer simulation experiments for the system using Hartmann –Shack wavefront sensor, deformable mirror with continuous surface plate and discrete actuators, direct slope wavefront reconstruction algorithm are conducted. The principle that each subaperture should be controlled mainly by 3 actuators is concluded.
In adaptive optics system, the effectiveness of wavefront correction is influenced gy the types of wavefront sensor and corrector, their relative configuration (matching) and wavefront reconstruction algorithm. In this paper, the computer simulation experiments for the system using Hartmann –Shack wavefront sensor, deformable mirror with continuous surface plate and discrete actuators, direct slope wavefront reconstruction algorithm are conducted. The principle that each subaperture should be controlled mainly by 3 actuators is concluded.
1996,
08.
Abstract:
A ferrite loaded RF cavity for Heavy Ion Research Facility in Lanzhou (HIRFL) Cooling Storage Ring (CSR) has been designed through calculation of two dimensional RF electromagnetic fields. The main parameters of RF system and the distribution of acceleration electric fields are obtained.
A ferrite loaded RF cavity for Heavy Ion Research Facility in Lanzhou (HIRFL) Cooling Storage Ring (CSR) has been designed through calculation of two dimensional RF electromagnetic fields. The main parameters of RF system and the distribution of acceleration electric fields are obtained.
1996,
08.
Abstract:
Second harmonic conversion efficiency of nearly 30% in type I phase matching BBO crystal has been demonstrated with Ti: sapphire femtosecond laser pulses. Analysis on frequency doubling is presented here in particular with femtosecond laser pulses.
Second harmonic conversion efficiency of nearly 30% in type I phase matching BBO crystal has been demonstrated with Ti: sapphire femtosecond laser pulses. Analysis on frequency doubling is presented here in particular with femtosecond laser pulses.
1996,
08.
Abstract:
Experiment of optical parameters diagnosis from LY-12 Al-target and carbon fibre target irradiation by 100J level XeCl excimer laser (308nm) has been researched. The reflectivity of the target surface changing with the input laser power density has been studied. The spectroscopy of laser –produced plasma and the formation of vapor plume have been optained.
Experiment of optical parameters diagnosis from LY-12 Al-target and carbon fibre target irradiation by 100J level XeCl excimer laser (308nm) has been researched. The reflectivity of the target surface changing with the input laser power density has been studied. The spectroscopy of laser –produced plasma and the formation of vapor plume have been optained.
1996,
08.
Abstract:
In this article, effects of positions of laser spots on the wall of a cavity on variations of non –uniform degree of illumination for capsule with time have been studied by both numerical simulation and qualitative analysis. The results show that the geometrical factors relative to the pole and the equator of the capsule vary with positions of laser spots in different patterns. According to the comparison between their quantity, the tends of the variation of non –uniform degree of illumination for the capsule with time can be divided in three types, which correspond to laser spots to be in three different regions, respectively. The results given by qualitative analysis are in good agreement with those given by numerical is simulation.
In this article, effects of positions of laser spots on the wall of a cavity on variations of non –uniform degree of illumination for capsule with time have been studied by both numerical simulation and qualitative analysis. The results show that the geometrical factors relative to the pole and the equator of the capsule vary with positions of laser spots in different patterns. According to the comparison between their quantity, the tends of the variation of non –uniform degree of illumination for the capsule with time can be divided in three types, which correspond to laser spots to be in three different regions, respectively. The results given by qualitative analysis are in good agreement with those given by numerical is simulation.
