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RSS1993 Vol. 05, No. 01
Recommend Articles
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1993,
05: 5-15.
Abstract:
A 100-J KrF laser facility is introduced in this paper.The Marx and diode voltages are 1.1MV and 620kV, respectively, with a diode current of 160kA and e- beam energy of 8kJ. The total gas pressure is 0.25MPa (F2 : Kr : Ar = 0.4 : 10 : 89.6). The reflectivities of the laser cavity mirrors are 96% and 25%, respectively.
A 100-J KrF laser facility is introduced in this paper.The Marx and diode voltages are 1.1MV and 620kV, respectively, with a diode current of 160kA and e- beam energy of 8kJ. The total gas pressure is 0.25MPa (F2 : Kr : Ar = 0.4 : 10 : 89.6). The reflectivities of the laser cavity mirrors are 96% and 25%, respectively.
1993,
05: 16-22.
Abstract:
This paper describes the electrical discharge characteristics in the optical cavity of a high-power KrF excimer laser amplifer operating as an oscilator. Several factors in connection with the output of laser energy have been studied. For the first time in China we successfully achieved a large volume(85cm × 3cm × 1.3cm) uniform KrF discharge with more than 130mJ laser output energy for a single pulse. In addition, detailed experimental results are presented here and further discussion and analysis on the related physical mechanism are presented.
This paper describes the electrical discharge characteristics in the optical cavity of a high-power KrF excimer laser amplifer operating as an oscilator. Several factors in connection with the output of laser energy have been studied. For the first time in China we successfully achieved a large volume(85cm × 3cm × 1.3cm) uniform KrF discharge with more than 130mJ laser output energy for a single pulse. In addition, detailed experimental results are presented here and further discussion and analysis on the related physical mechanism are presented.
1993,
05: 23-28.
Abstract:
A 100J level XeCl laser pumped by an intense relativistic electron beam -FLASH IT was constructed at Northwest Institute of Nuclear Technology. The cathode of diode for laser pumping is a 15cm x 60cm multi -point copper plate of graphite plate. The anode and pressure foils are both 25 micron Ti. The voltage of diode is measured to be 650-750kV and the current 290-350 kA. The pump power density ranges between 1.5-2.0MW/cm3. The aperture of laser cell is 20cm × 20cm and the effective excitation volume is 24 liters. We have obtained the laser output energy of 136J with a parallel-plane resonator and l.5mrad divergence angle from an unstable resonator. The laser power is measured to be more than 109W.
A 100J level XeCl laser pumped by an intense relativistic electron beam -FLASH IT was constructed at Northwest Institute of Nuclear Technology. The cathode of diode for laser pumping is a 15cm x 60cm multi -point copper plate of graphite plate. The anode and pressure foils are both 25 micron Ti. The voltage of diode is measured to be 650-750kV and the current 290-350 kA. The pump power density ranges between 1.5-2.0MW/cm3. The aperture of laser cell is 20cm × 20cm and the effective excitation volume is 24 liters. We have obtained the laser output energy of 136J with a parallel-plane resonator and l.5mrad divergence angle from an unstable resonator. The laser power is measured to be more than 109W.
1993,
05: 29-36.
Abstract:
In this paper, one-dimensional kinetics simulation was studied on e-beam pumped KrF laser in Ar/Kr/F2 mixtures, taking account of 24 species particles and 119 reaction channels. Its physical mechanism and mathmatical handling method were studied in detail.
Using this model, simulations were performed and compared with the experimental results abroad and were in good agreement with them. Also simulations were performed and compared with the hundred-joule excimer laser, some laser parameters varying on time and longitudinal position were obtained and analysed.The theoretical results of one-dimensional model were compared with that of zero -dimensional model finally.
In this paper, one-dimensional kinetics simulation was studied on e-beam pumped KrF laser in Ar/Kr/F2 mixtures, taking account of 24 species particles and 119 reaction channels. Its physical mechanism and mathmatical handling method were studied in detail.
Using this model, simulations were performed and compared with the experimental results abroad and were in good agreement with them. Also simulations were performed and compared with the hundred-joule excimer laser, some laser parameters varying on time and longitudinal position were obtained and analysed.The theoretical results of one-dimensional model were compared with that of zero -dimensional model finally.
1993,
05: 37-41.
Abstract:
The free running XeF (C-A)lasing was achieved in a commercial discharge excited excimer laser at reduced gas pressure of 0.22MPa and moderate pump rate of 2.76MW/cm3, using a four-component gas mixture doped by Kr with a net peak gain of 1.24%/cm. The laser output, energy density and intrinsic efficiency were 1.17mJ, 9mJ/ L and 0.016%, respectively. The laser spectrum showed a peak wavelength at 477nm and a bandwidth of 32nm (FWHM).
The free running XeF (C-A)lasing was achieved in a commercial discharge excited excimer laser at reduced gas pressure of 0.22MPa and moderate pump rate of 2.76MW/cm3, using a four-component gas mixture doped by Kr with a net peak gain of 1.24%/cm. The laser output, energy density and intrinsic efficiency were 1.17mJ, 9mJ/ L and 0.016%, respectively. The laser spectrum showed a peak wavelength at 477nm and a bandwidth of 32nm (FWHM).
1993,
05: 42-44.
Abstract:
A setup for measuring beam quality of a CW HF (DF) chemical laser with an unstable cavity is described. The results of the beam quality measurement are presented.
A setup for measuring beam quality of a CW HF (DF) chemical laser with an unstable cavity is described. The results of the beam quality measurement are presented.
1993,
05: 45-50.
Abstract:
A high voltage pulse generator capable of repetitive operation for exciting a KrF laser amplifier is described. It consists of a constant current source, an energy storage capacitor, a transfer switch, a low impedance Blumlein line, and a multichannel rail-gap switch. The configurations of the Blumlein line and the rail -gap switch are presented. The performance characteristics of the circuits in the charge and discharge loops are analysed. The adjustment of the generator is performed and the experimental results are given. With DC charge voltage 30kV of the storage capacitor, the Blumlein line output pulse up to 60kV with a pulse width of 80ns and a rise time of 30ns is obtained.
A high voltage pulse generator capable of repetitive operation for exciting a KrF laser amplifier is described. It consists of a constant current source, an energy storage capacitor, a transfer switch, a low impedance Blumlein line, and a multichannel rail-gap switch. The configurations of the Blumlein line and the rail -gap switch are presented. The performance characteristics of the circuits in the charge and discharge loops are analysed. The adjustment of the generator is performed and the experimental results are given. With DC charge voltage 30kV of the storage capacitor, the Blumlein line output pulse up to 60kV with a pulse width of 80ns and a rise time of 30ns is obtained.
1993,
05: 51-60.
Abstract:
Experiments to study the laser plasma angular distribution and the absorption scaling laws for planar targets are reported. Gaussian (0.3 to 2.2ns) 1.06μm laser pulse with energy from 2 to 50J at average laser intensity of 1.8×1013 to 1.1 × 1015W/cm2, were used to irradiate thick, Au, Ag, Ti, Al, and C8H8 targets. The absorption was measured with plasma calorimeters. The experimental data were fitted with exponential functions. Scaling relations of the absorption efficiencies as function of laser intensity, pulse duration, and target material atomic number were presented, respectively. The scaling relations of absorption efficiency are qualitatively consistent with theoretical relations of the inverse- bremsstrahlung absorption.
Experiments to study the laser plasma angular distribution and the absorption scaling laws for planar targets are reported. Gaussian (0.3 to 2.2ns) 1.06μm laser pulse with energy from 2 to 50J at average laser intensity of 1.8×1013 to 1.1 × 1015W/cm2, were used to irradiate thick, Au, Ag, Ti, Al, and C8H8 targets. The absorption was measured with plasma calorimeters. The experimental data were fitted with exponential functions. Scaling relations of the absorption efficiencies as function of laser intensity, pulse duration, and target material atomic number were presented, respectively. The scaling relations of absorption efficiency are qualitatively consistent with theoretical relations of the inverse- bremsstrahlung absorption.
1993,
05: 61-69.
Abstract:
This paper briefly describes the design consideration, structure features and regulating process of the pulsed power system for 3.3MeV LIA. It is also discussed how to use the voltage transport formula of the system given here to predicate experimental results and to discover trouble position.
According to the data acquired from experimental results, we analyse the systematic synchronism of the switches. Some ways are suggested to further improve the switch systematic synchronism.
This paper briefly describes the design consideration, structure features and regulating process of the pulsed power system for 3.3MeV LIA. It is also discussed how to use the voltage transport formula of the system given here to predicate experimental results and to discover trouble position.
According to the data acquired from experimental results, we analyse the systematic synchronism of the switches. Some ways are suggested to further improve the switch systematic synchronism.
1993,
05: 70-74.
Abstract:
Recently, on the basis of the success in Ne-like GeX -ray laser experiment of the electron-collision scheme, the space -profile characteristics of the plasma were measured and analyzed. The dimention of the plasma profile was first determined. In addition, the effect of the laser parameters and target structures on plasma characteristics was also studied.
Recently, on the basis of the success in Ne-like GeX -ray laser experiment of the electron-collision scheme, the space -profile characteristics of the plasma were measured and analyzed. The dimention of the plasma profile was first determined. In addition, the effect of the laser parameters and target structures on plasma characteristics was also studied.
1993,
05: 75-80.
Abstract:
HIRFL beam (12C6+) emittance has been measured with "Three-Profile Method" in which the beam sizes at three different locations in a field -free drift space are measured by three secondary emission multi - wire profile monitors. Measurement results are presented here. Particular emphasis has been laid on the calculations and discussions relating theoretical error of emittance measurements with the separation of the three profile monitors, the location and size of the beam waist so that the optimum conditions of emittance measurements could be determined.
HIRFL beam (12C6+) emittance has been measured with "Three-Profile Method" in which the beam sizes at three different locations in a field -free drift space are measured by three secondary emission multi - wire profile monitors. Measurement results are presented here. Particular emphasis has been laid on the calculations and discussions relating theoretical error of emittance measurements with the separation of the three profile monitors, the location and size of the beam waist so that the optimum conditions of emittance measurements could be determined.
1993,
05: 81-87.
Abstract:
Aluminium attenuation foil with various thickness was fabricated by different methods, and the mass thickness and thickness homogeneity of the foil were measured by a computerized α mass thickness measurement apparatus. The surface chemical component and depth distribution in the foil were analysed by using Auger Electron Spectroscopy (AES). The chemical components of oxide layer were renealed by Al K.LL Auger characteristic peak and the change of oxide layer thickness with storage time were measured, Also, the upper limit of other impurity contents of the foil were discussed.
Aluminium attenuation foil with various thickness was fabricated by different methods, and the mass thickness and thickness homogeneity of the foil were measured by a computerized α mass thickness measurement apparatus. The surface chemical component and depth distribution in the foil were analysed by using Auger Electron Spectroscopy (AES). The chemical components of oxide layer were renealed by Al K.LL Auger characteristic peak and the change of oxide layer thickness with storage time were measured, Also, the upper limit of other impurity contents of the foil were discussed.
1993,
05: 88-92.
Abstract:
In this paper, we discuss the experiment conducted onLF-11 laser facility. The aim is to study the irradiation damage of X -ray reflction mirrors that were used in the double -pass amplification experiment of Ne-like Ge X -ray lasers . The results indicated that the mirror's life time was 440ps when it was irradiated by 113MW/cm2 X rays and 227 MW/cm2 scattered laser light. When the intensities of X rays and scattered laser light on the mirror were 50 MW/cm2 and 101 MW/cm2, respectively, the mirror's life time was 700ps.
In this paper, we discuss the experiment conducted onLF-11 laser facility. The aim is to study the irradiation damage of X -ray reflction mirrors that were used in the double -pass amplification experiment of Ne-like Ge X -ray lasers . The results indicated that the mirror's life time was 440ps when it was irradiated by 113MW/cm2 X rays and 227 MW/cm2 scattered laser light. When the intensities of X rays and scattered laser light on the mirror were 50 MW/cm2 and 101 MW/cm2, respectively, the mirror's life time was 700ps.
1993,
05: 93-101.
Abstract:
The Beijing Free Electron Laser (BFEL) is a Compton regime, IR PEL oscillator. In the article, an injection experiment design has been put forward. A reduction in laser startup time and an increase in laser output energy can be obtained by seed injection from an external Q-switch CO2 laser. Numerical simulations of BFEL injection plan show that with an injecting laser 105 higher than the spontaneous emission in the optical cavity, the startup time is reduced by 35% and the ouptut laser energy is increased by 2 times.
The Beijing Free Electron Laser (BFEL) is a Compton regime, IR PEL oscillator. In the article, an injection experiment design has been put forward. A reduction in laser startup time and an increase in laser output energy can be obtained by seed injection from an external Q-switch CO2 laser. Numerical simulations of BFEL injection plan show that with an injecting laser 105 higher than the spontaneous emission in the optical cavity, the startup time is reduced by 35% and the ouptut laser energy is increased by 2 times.
1993,
05: 102-110.
Abstract:
The design of De-Qing circuits for stable operations is introduced. This paper indicates that there exists a finite range for stable operation theoretically and experimentally. The range depends on the selected component parameters, and the expected regulation accuracy.
The design of De-Qing circuits for stable operations is introduced. This paper indicates that there exists a finite range for stable operation theoretically and experimentally. The range depends on the selected component parameters, and the expected regulation accuracy.
1993,
05: 111-117.
Abstract:
An uniform rectangular Intense Relativistic Electron Beam is important to KrF excimer.The main factors that affect the uniformity of e -beam include two aspects: one is the diode design and diode electrical field, the other is the self-magnetic field. In this paper the effect of self-magnetic field on the uniformity of e -beam is studied. The intensity distribution of self-magnetic field is calculated in two cases. In one case, the retangular e-beam is supposed to be infinite long along z -direction, in the other case, finite long. The trajectories of the moving electrons in self-magnetic field are also calculated. From these calculation the beam pinching sections at 6-cm distance from diode cathode in z-direction are discribed. In the calculation, the electrical field force is taken into account, and the scattering effect of e -beam of foils and Hibachi is neglected. This is useful to improving laser quality of hundred joule level KrF excimer laser.
An uniform rectangular Intense Relativistic Electron Beam is important to KrF excimer.The main factors that affect the uniformity of e -beam include two aspects: one is the diode design and diode electrical field, the other is the self-magnetic field. In this paper the effect of self-magnetic field on the uniformity of e -beam is studied. The intensity distribution of self-magnetic field is calculated in two cases. In one case, the retangular e-beam is supposed to be infinite long along z -direction, in the other case, finite long. The trajectories of the moving electrons in self-magnetic field are also calculated. From these calculation the beam pinching sections at 6-cm distance from diode cathode in z-direction are discribed. In the calculation, the electrical field force is taken into account, and the scattering effect of e -beam of foils and Hibachi is neglected. This is useful to improving laser quality of hundred joule level KrF excimer laser.
1993,
05: 118-128.
Abstract:
The kinetic theory of Cherenkov free-electron lasers was developed and used to study the devices operated in the far infrared portion of the spectrum. Comparison with free-electron lasers and cyclotron autoresonance masers, which can also work as far infrared devices, was also carried out.
The kinetic theory of Cherenkov free-electron lasers was developed and used to study the devices operated in the far infrared portion of the spectrum. Comparison with free-electron lasers and cyclotron autoresonance masers, which can also work as far infrared devices, was also carried out.
1993,
05: 129-133.
Abstract:
In this paper, the basic equations to describe the superradiation of FEL synchrotron sidebands and also the solving process and the corresponding numerical calculation code for these equations are presented. Using this code, we have quantitively studied the spectrum and the intensity of sideband superradiation systematically. The numerical results show that the induced radiation is dominant for sideband radiation. This result is consistent with the theoretical analysis.
In this paper, the basic equations to describe the superradiation of FEL synchrotron sidebands and also the solving process and the corresponding numerical calculation code for these equations are presented. Using this code, we have quantitively studied the spectrum and the intensity of sideband superradiation systematically. The numerical results show that the induced radiation is dominant for sideband radiation. This result is consistent with the theoretical analysis.
1993,
05: 134-140.
Abstract:
A cylindrical gas -flow proportional counter with a side window is described in this paper. Which can be used to measure soft X rays in the energy range of 183 ~ 933eV. Its counter gases are P -10 or helium isobutane gases. The pressure is 0.11MPa. The counter has a inner diameter of 25mm and window diameter of 0.3mm made of 80-90μg ·cm2 formvar.
The specialities of this countes are as following: （1） Its window is thin, and has a high transmission for soft X rays. （2）It works in gas-flow form, and has a long lifetime. （3）It has a high energy resolution. （4） Its counting efficency is high up to 1 x 1014s-1. （5） It can work in a wide energy range of 0.183-10keV. （6 ）Its window material, thickness and diameter can be easily replaced.
A cylindrical gas -flow proportional counter with a side window is described in this paper. Which can be used to measure soft X rays in the energy range of 183 ~ 933eV. Its counter gases are P -10 or helium isobutane gases. The pressure is 0.11MPa. The counter has a inner diameter of 25mm and window diameter of 0.3mm made of 80-90μg ·cm2 formvar.
The specialities of this countes are as following: （1） Its window is thin, and has a high transmission for soft X rays. （2）It works in gas-flow form, and has a long lifetime. （3）It has a high energy resolution. （4） Its counting efficency is high up to 1 x 1014s-1. （5） It can work in a wide energy range of 0.183-10keV. （6 ）Its window material, thickness and diameter can be easily replaced.
1993,
05: 141-147.
Abstract:
On the basis of the principles of virtual cathode microwave generator, this paper gives a vircator experiment arrangement with high impedance and low beam current, and presents numerical calculation and analysis. The experiment measurement results agree with the theoretical calculation. The output peak power obtained in 3cm wave band is bigger than or equal to 20MW.
On the basis of the principles of virtual cathode microwave generator, this paper gives a vircator experiment arrangement with high impedance and low beam current, and presents numerical calculation and analysis. The experiment measurement results agree with the theoretical calculation. The output peak power obtained in 3cm wave band is bigger than or equal to 20MW.
1993,
05: 148-152.
Abstract:
This paper introduces a new data acquisition and processing system for multi-channel signals. This system mainly consists of oscilloscopes, digitizing camera systems (dcs) and a personal computer. It can be used to acquire and process multi-channel instantaneous sig nal pulses of ns rise time.
This paper introduces a new data acquisition and processing system for multi-channel signals. This system mainly consists of oscilloscopes, digitizing camera systems (dcs) and a personal computer. It can be used to acquire and process multi-channel instantaneous sig nal pulses of ns rise time.
1993,
05: 153-160.
Abstract:
In part n of this monosraph, the matrix optical methods and Lie algebraic theory are used for analyzing beam transformation and propagation through optical systems, including axis -asymmetric systems and optical arrays, as well as dispersive Gaussian pulse propagation. Some novel methods and useful tools, such as the generalized ABCD law and Lie methods are introduced and illustrated with typical application examples.
In part n of this monosraph, the matrix optical methods and Lie algebraic theory are used for analyzing beam transformation and propagation through optical systems, including axis -asymmetric systems and optical arrays, as well as dispersive Gaussian pulse propagation. Some novel methods and useful tools, such as the generalized ABCD law and Lie methods are introduced and illustrated with typical application examples.
