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RSS1997 Vol. 09, No. 02
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1997,
09.
Abstract:
In this paper, a device of azimuthal magnetic field is described, the circuit current and azimuthal magnetic field are measured, synchronizer between FLASH-2 and the magnetic field is introduced, and the initial result of the relation between the current of center wire and the generated hard X-ray is also given.
In this paper, a device of azimuthal magnetic field is described, the circuit current and azimuthal magnetic field are measured, synchronizer between FLASH-2 and the magnetic field is introduced, and the initial result of the relation between the current of center wire and the generated hard X-ray is also given.
1997,
09.
Abstract:
A positive branch confocal unstable resonator suitable for CW supersonic chemical oxygen-iodine lasers (COIL) has been designed and studied. Experimental results of the relation of magnification vs output power and beam quality are given with theoretical analysis.
A positive branch confocal unstable resonator suitable for CW supersonic chemical oxygen-iodine lasers (COIL) has been designed and studied. Experimental results of the relation of magnification vs output power and beam quality are given with theoretical analysis.
1997,
09.
Abstract:
This paper presents the calculation and analysis on the gain characteristics of double-side pumped Ti:sapphire laser amplifiers. Chirped-pulse multipass amplification in Ti: sapphire experiments has been , for the first time in China, conducted here with 106 overall gain and 0.8mJ output energy.
This paper presents the calculation and analysis on the gain characteristics of double-side pumped Ti:sapphire laser amplifiers. Chirped-pulse multipass amplification in Ti: sapphire experiments has been , for the first time in China, conducted here with 106 overall gain and 0.8mJ output energy.
1997,
09.
Abstract:
This paper gives theoretical model and calculated results of inductive store power-conditioning system of transmission line with exploding wires opening switch. Effects of exploding wires cross-section, load resistance etc on performance of the power conditional system are discussed.
This paper gives theoretical model and calculated results of inductive store power-conditioning system of transmission line with exploding wires opening switch. Effects of exploding wires cross-section, load resistance etc on performance of the power conditional system are discussed.
1997,
09.
Abstract:
Using escape probability method,the effects of radiation trapping on inversion and gain of electron-collisional excitation pumping X-ray laser lines are studied in this paper.As an example,the dependence of the inversion and gain of laser lines at 19.6nm and 23.2nm and 23.6nm in neon-like germanium ion on spatial width of gain region D R and velocity gradient of lasing medium dV/dZ are discussed.
Using escape probability method,the effects of radiation trapping on inversion and gain of electron-collisional excitation pumping X-ray laser lines are studied in this paper.As an example,the dependence of the inversion and gain of laser lines at 19.6nm and 23.2nm and 23.6nm in neon-like germanium ion on spatial width of gain region D R and velocity gradient of lasing medium dV/dZ are discussed.
1997,
09.
Abstract:
Holographic interferometric data are interpreted in detail, and Abel inversion of measurements of optical path length through refracting cylindrical symmetric plasmas is discussed and numerically studied. By expanding refractive index of plasma as truncated Fourier Bessel series and determining the expanded coefficients in the least-mean-square sense, Abel inversion is realized. Numerical results show that, if electron density of plasma is low, i.e., about one tenth of the critical density of probe light, the precision of the method used in the paper is satisfying, even if the object plane of image system deviates a little from the symmetrical axial of plasmas.
Holographic interferometric data are interpreted in detail, and Abel inversion of measurements of optical path length through refracting cylindrical symmetric plasmas is discussed and numerically studied. By expanding refractive index of plasma as truncated Fourier Bessel series and determining the expanded coefficients in the least-mean-square sense, Abel inversion is realized. Numerical results show that, if electron density of plasma is low, i.e., about one tenth of the critical density of probe light, the precision of the method used in the paper is satisfying, even if the object plane of image system deviates a little from the symmetrical axial of plasmas.
1997,
09.
Abstract:
The anomalous skin effect of ultrashort laser pulse on plasma heating is studied using a two-dimensional multi-time-scale fully electromagnetic relativistic particle simulation code. Reasonable physical description is undertaken.
The anomalous skin effect of ultrashort laser pulse on plasma heating is studied using a two-dimensional multi-time-scale fully electromagnetic relativistic particle simulation code. Reasonable physical description is undertaken.
1997,
09.
Abstract:
For high power gas and chemical laser,a new type of aerodynamic window jet injecting aerodynamic window(JIAW) is proposed. In order to realize the influence of the jet injection on optical quality and the application possibility of the JIAW,the optical quality is measured with the Hartmann diagnostic apparatus. With the test, the optical characteristics of the JIAW under different throat area of the jet injecting nozzle and the stagnation pressure of the jet are presented. The results show that, the JIAW can promise a good optical quality at present experiment conditions except the condition of dH=2.5mm and stagnation pressure of 0.5MPa.
For high power gas and chemical laser,a new type of aerodynamic window jet injecting aerodynamic window(JIAW) is proposed. In order to realize the influence of the jet injection on optical quality and the application possibility of the JIAW,the optical quality is measured with the Hartmann diagnostic apparatus. With the test, the optical characteristics of the JIAW under different throat area of the jet injecting nozzle and the stagnation pressure of the jet are presented. The results show that, the JIAW can promise a good optical quality at present experiment conditions except the condition of dH=2.5mm and stagnation pressure of 0.5MPa.
1997,
09.
Abstract:
This paper presents the visible-fluorescence method for the measurement of the total tritium quantity in ICF target. As a nondestructive method, it may be used not only in the measurement of direct-drive targets, but also in the monitoring of wide variety of indirect-drive cavity targets. Basing on the practically measuring results of obtained on “shenguang” in 1992, this paper gives a tentative plan for application of this method in the measurement of DT quantity in plastic targets and the scale factors which are needed in the case of absolute measurement, especially the importance and necessary of development of high sensitivity fluorescence negative or detectors.
This paper presents the visible-fluorescence method for the measurement of the total tritium quantity in ICF target. As a nondestructive method, it may be used not only in the measurement of direct-drive targets, but also in the monitoring of wide variety of indirect-drive cavity targets. Basing on the practically measuring results of obtained on “shenguang” in 1992, this paper gives a tentative plan for application of this method in the measurement of DT quantity in plastic targets and the scale factors which are needed in the case of absolute measurement, especially the importance and necessary of development of high sensitivity fluorescence negative or detectors.
1997,
09.
Abstract:
The principle and procedure of aligning a confocal positive branch unstable resonator with small-mirror method are presented in this paper. The small-mirror method is compared with some others, experimental result and theory analysis have shown that the small-mirror method has a great part of other methods?advantages, and that it is suitable to be used when the accurate focus point position of high power laser beam in far-field should be located.
The principle and procedure of aligning a confocal positive branch unstable resonator with small-mirror method are presented in this paper. The small-mirror method is compared with some others, experimental result and theory analysis have shown that the small-mirror method has a great part of other methods?advantages, and that it is suitable to be used when the accurate focus point position of high power laser beam in far-field should be located.
1997,
09.
Abstract:
The operating function and the characteristic of 500kV modulation-type accelerator are discussed. The parameters and the keys of each part of circuit design are introduced. On condition that pulse is single and the charging voltage, the distance between cathode and anoding, the guide magnetic field are adjustable, the primary result is obtained.
The operating function and the characteristic of 500kV modulation-type accelerator are discussed. The parameters and the keys of each part of circuit design are introduced. On condition that pulse is single and the charging voltage, the distance between cathode and anoding, the guide magnetic field are adjustable, the primary result is obtained.
1997,
09.
Abstract:
The processes of ignition and burning in the fusion system of D-3He with a small number of neutrons have been analyzed and the corresponing conditions of ignition and burning have been given in this paper. Several typical physics models of D-3He reaction have also been simulated numerically. The results further demonstrate that the fusion system of D-3He is the optimum candidate of the fusion power with a small number of neutrons in future.
The processes of ignition and burning in the fusion system of D-3He with a small number of neutrons have been analyzed and the corresponing conditions of ignition and burning have been given in this paper. Several typical physics models of D-3He reaction have also been simulated numerically. The results further demonstrate that the fusion system of D-3He is the optimum candidate of the fusion power with a small number of neutrons in future.
1997,
09.
Abstract:
Numerical simulation of the combustion driven CW DF chemical laser are performed, the performance of C2H4/He laser under high cavity pressure is studied. The optical cavity pressure, lasing intensity, outcoupling power and chemical efficiency of different nozzle arrays are given. The results showed that: high cavity pressure require not only high pressure of combustor but also optimal nozzle arrays.
Numerical simulation of the combustion driven CW DF chemical laser are performed, the performance of C2H4/He laser under high cavity pressure is studied. The optical cavity pressure, lasing intensity, outcoupling power and chemical efficiency of different nozzle arrays are given. The results showed that: high cavity pressure require not only high pressure of combustor but also optimal nozzle arrays.
1997,
09.
Abstract:
In this paper, the relationships of utilization of Cl2 and O2（1D ）yield versus SOG total working pressure are studied experimentally. Simple theoretical analysis indicates that the optimum Cl2 partial pressure is about 2.13kPa.
In this paper, the relationships of utilization of Cl2 and O2（1D ）yield versus SOG total working pressure are studied experimentally. Simple theoretical analysis indicates that the optimum Cl2 partial pressure is about 2.13kPa.
1997,
09.
Abstract:
We have constructed and tested a glow discharge chamber with a clear aperture of 300mm 300mm . By using the 揵uttons?cathode and the automatic preionization cathode, we have got uniform glow discharge in large area. We have measured delay time of the glow discharge and the plasma resistance under various conditions. So the optimal conditions forming uniform glow discharge in large area were discovered.
We have constructed and tested a glow discharge chamber with a clear aperture of 300mm 300mm . By using the 揵uttons?cathode and the automatic preionization cathode, we have got uniform glow discharge in large area. We have measured delay time of the glow discharge and the plasma resistance under various conditions. So the optimal conditions forming uniform glow discharge in large area were discovered.
1997,
09.
Abstract:
A set of equations for waveguide free-electron laser oscillators is derived,which can deal with 3D problems such as the diffraction, the hole-coupling output, and the misalignment. The 3D effects and transverse structure of optical field of CAEP FIR FEL are studied with an INEX model.
A set of equations for waveguide free-electron laser oscillators is derived,which can deal with 3D problems such as the diffraction, the hole-coupling output, and the misalignment. The 3D effects and transverse structure of optical field of CAEP FIR FEL are studied with an INEX model.
1997,
09.
Abstract:
This paper investigates the problem of an ejector used in a pressure recovery system for chemical oxygen-iodine laser(COIL). For the purpose to reduce the scale of an ejector as well as to increase pressure ratio prec/p, it is better to use the eject gas having small molecular weight and specific heat ratio. Another method to increase the pressure ratio prec/p is to increase the temperature and Mach number of the eject gas.
This paper investigates the problem of an ejector used in a pressure recovery system for chemical oxygen-iodine laser(COIL). For the purpose to reduce the scale of an ejector as well as to increase pressure ratio prec/p, it is better to use the eject gas having small molecular weight and specific heat ratio. Another method to increase the pressure ratio prec/p is to increase the temperature and Mach number of the eject gas.
1997,
09.
Abstract:
In this paper, the theoretical frame for beam transport provided in reference[1] was checked by numerical calculation in the cases of pure and mixing assemblages with constant and periodical linear force. It shows that the results of numerical method are completely agree with the particle tracing simulation used commonly, but the former is more timesaving with less error fluctuation.
In this paper, the theoretical frame for beam transport provided in reference[1] was checked by numerical calculation in the cases of pure and mixing assemblages with constant and periodical linear force. It shows that the results of numerical method are completely agree with the particle tracing simulation used commonly, but the former is more timesaving with less error fluctuation.
1997,
09.
Abstract:
The process of the surface oxidizing of Nd thin films used in X-ray laser experiment is studied through AES method combined with Ar ion beam etching. The experimental results, which agree well with that of RBS, show that the surface oxidisation of Nd is saturated just 20~30 minutes after the sample exposed in air, the max thickness of oxide layer is about 20nm, and the main composition of oxide layer is NdO.
The process of the surface oxidizing of Nd thin films used in X-ray laser experiment is studied through AES method combined with Ar ion beam etching. The experimental results, which agree well with that of RBS, show that the surface oxidisation of Nd is saturated just 20~30 minutes after the sample exposed in air, the max thickness of oxide layer is about 20nm, and the main composition of oxide layer is NdO.
1997,
09.
Abstract:
The experimental studies of photocathode driven by a laser are reported in this paper. The experimental systems including the D-C voltage vacuum chamber and measurement apparatus are given. Also we will present the experimental results and discussions of LaB6, pure metals (Cu,Sm) and Cs2Te semiconductor photocathode. The quantum efficiencies of photocathodes are 6 10- 4、3.8 10- 4、11.6 10- 4 and (2~6) 10- 2, respectively, the corresponding photocurrent densities of 70A/cm2、50 A/cm2、102A/cm2 and 57A/cm2 are obtained. Using the pepper pot method, the normalized beam emittances for these materials are about 10p mm· mrad and the corresponding normalized brightnesses are about 1010A/m2× rad2.
The experimental studies of photocathode driven by a laser are reported in this paper. The experimental systems including the D-C voltage vacuum chamber and measurement apparatus are given. Also we will present the experimental results and discussions of LaB6, pure metals (Cu,Sm) and Cs2Te semiconductor photocathode. The quantum efficiencies of photocathodes are 6 10- 4、3.8 10- 4、11.6 10- 4 and (2~6) 10- 2, respectively, the corresponding photocurrent densities of 70A/cm2、50 A/cm2、102A/cm2 and 57A/cm2 are obtained. Using the pepper pot method, the normalized beam emittances for these materials are about 10p mm· mrad and the corresponding normalized brightnesses are about 1010A/m2× rad2.
1997,
09.
Abstract:
This paper describes a frequency stabilization system which uses the frequency discriminating method with output energy-input frequency relationship of a resonance cavity. To integrate the output signal from the cavities not only reduces the disturbance from the modulating pulse, but also increases the frequency stability. A high efficiency stepping motor servo subsystem is used, the power of the subsystem is decreased evidently. The stabilized operating frequency of the LINAC is 2856MHz and the unstability of the system is not larger than ± 7 10- 6.
This paper describes a frequency stabilization system which uses the frequency discriminating method with output energy-input frequency relationship of a resonance cavity. To integrate the output signal from the cavities not only reduces the disturbance from the modulating pulse, but also increases the frequency stability. A high efficiency stepping motor servo subsystem is used, the power of the subsystem is decreased evidently. The stabilized operating frequency of the LINAC is 2856MHz and the unstability of the system is not larger than ± 7 10- 6.
1997,
09.
Abstract:
In this paper, the configuration and performance of the model HIREFS（High Resolution Erect Field Spectrometer）Spectrometer are described. The instrument is used to observe the space-resolved spectra of Ti slab targets illuminated with prepulse technique. The Ne-like Ti 32.6nm soft x-ray lasing is obtained and discussed.
In this paper, the configuration and performance of the model HIREFS（High Resolution Erect Field Spectrometer）Spectrometer are described. The instrument is used to observe the space-resolved spectra of Ti slab targets illuminated with prepulse technique. The Ne-like Ti 32.6nm soft x-ray lasing is obtained and discussed.
1997,
09.
Abstract:
Using one dimensional kinetics model, theoretical simulation was studied on e-beam pumped triatonic Kr2F excimer laser in Ar/Kr/F2 mixtures. The calculation results revealed the direction to increase Kr2F excimer laser energy in the experiment. The calculation laser output energy was up to mJ. All calculation results above were demonstrated in the experiments.
Using one dimensional kinetics model, theoretical simulation was studied on e-beam pumped triatonic Kr2F excimer laser in Ar/Kr/F2 mixtures. The calculation results revealed the direction to increase Kr2F excimer laser energy in the experiment. The calculation laser output energy was up to mJ. All calculation results above were demonstrated in the experiments.
1997,
09.
Abstract:
In this paper, a two-dimensional finite element model is used to evaluate the temperature and thermal-softening distribution of coated 30CrMnSiA steel plate induced by different temporally and spacially distributed CW laser. The simulation results show that different laser intensity spacial distributions give rise to different target surface temperature distributions and material thermal softening distributions, but both the difference in temperature field and heat softening distributions are all much smaller than that of laser spacial profiles. Laser wave has influence on target temperature rise history, but has little influence on final temperature and its distribution.
In this paper, a two-dimensional finite element model is used to evaluate the temperature and thermal-softening distribution of coated 30CrMnSiA steel plate induced by different temporally and spacially distributed CW laser. The simulation results show that different laser intensity spacial distributions give rise to different target surface temperature distributions and material thermal softening distributions, but both the difference in temperature field and heat softening distributions are all much smaller than that of laser spacial profiles. Laser wave has influence on target temperature rise history, but has little influence on final temperature and its distribution.
1997,
09.
Abstract:
Electron-impact excitation collision strength W (nl-n抣?/I>)，(3≤n≤7，4≤n?/FONT>≤7) among configuration average levels for the Cu-like Ions Ba,Nd,Gd,Yb,Au,Pb have been calculated systematically using the quasirelativistic distorted-wave methods. In addition, the collision strength in high energy limit have been calculated. The data for the collision strength or thermally averaged rate coefficient over the entire range of energy or temperature have been evaluated by a least-squares spline fitting procedure. As a result, the collision strength with arbitrary electron energy and rate coefficient with arbitrary temperature can be determined by ten parameters. Some scaled rules have also been given in the paper.
Electron-impact excitation collision strength W (nl-n抣?/I>)，(3≤n≤7，4≤n?/FONT>≤7) among configuration average levels for the Cu-like Ions Ba,Nd,Gd,Yb,Au,Pb have been calculated systematically using the quasirelativistic distorted-wave methods. In addition, the collision strength in high energy limit have been calculated. The data for the collision strength or thermally averaged rate coefficient over the entire range of energy or temperature have been evaluated by a least-squares spline fitting procedure. As a result, the collision strength with arbitrary electron energy and rate coefficient with arbitrary temperature can be determined by ten parameters. Some scaled rules have also been given in the paper.
1997,
09.
Abstract:
This is the first experimental result on a 2kW chemical oxygen iodine laser (COIL) using an unstable ring resonator with 90°beam rotation(UR90°). The distribution of near-field phase and far-field intensity were measured. The measured value of beam quality was b =3~4 while the average laser power was 2kW.
This is the first experimental result on a 2kW chemical oxygen iodine laser (COIL) using an unstable ring resonator with 90°beam rotation(UR90°). The distribution of near-field phase and far-field intensity were measured. The measured value of beam quality was b =3~4 while the average laser power was 2kW.
1997,
09.
Abstract:
The corkscrew oscillation of beam centroid in the linac makes the increment not only of the effective spot-size of the electron beam extracted from an accelerator but also of the normalized emittance of the beam. The expressions of the emittance growth due to the corkscrew oscillation induced by two sources are analytically given in this paper. The sources are the tilted beam injection and the statistical misalignments of the solenoidal focusing.
The corkscrew oscillation of beam centroid in the linac makes the increment not only of the effective spot-size of the electron beam extracted from an accelerator but also of the normalized emittance of the beam. The expressions of the emittance growth due to the corkscrew oscillation induced by two sources are analytically given in this paper. The sources are the tilted beam injection and the statistical misalignments of the solenoidal focusing.
1997,
09.
Abstract:
In this paper we present a numerical simulation programme about eddy current influences of waveguide pipe in pulsed magnetic field. We study effects of waveguide conductivity s , pipe radius R, wall thickness D R and excitation current angular frequency w on eddy current. Finally, we calculate influences of eddy current of stainless steel (1Cr18Ni9Ti) pipe which will be used in diode-relativistic klystron experiment.
In this paper we present a numerical simulation programme about eddy current influences of waveguide pipe in pulsed magnetic field. We study effects of waveguide conductivity s , pipe radius R, wall thickness D R and excitation current angular frequency w on eddy current. Finally, we calculate influences of eddy current of stainless steel (1Cr18Ni9Ti) pipe which will be used in diode-relativistic klystron experiment.
