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RSS2003 Vol. 15, No. 02
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2003,
15.
Abstract:
Based on the complex ray concept, the decomposition of 3×3 complex matrices is studied using the matrix method in optics. As two application examples, the equivalent transformation of the misaligned Gaussian lens and Fourier transformation system is analyzed. It is shown that the augmented matrix of misaligned complex optical systems can be represented by an ordered product of basic matrices.
Based on the complex ray concept, the decomposition of 3×3 complex matrices is studied using the matrix method in optics. As two application examples, the equivalent transformation of the misaligned Gaussian lens and Fourier transformation system is analyzed. It is shown that the augmented matrix of misaligned complex optical systems can be represented by an ordered product of basic matrices.
2003,
15.
Abstract:
The basic Boltzmann equation in reference is improved. Compared with the basic equation, the improved Boltzmann equation can describe the collision between electron and fundamental state argon more perfectly, and can calculate the electron distribution in the whole energy range. With the basic Boltzmann equation and the improved Boltzmann equation, the high energy electron distributions, whose energy is larger than the first excited state energy (11.56eV), are calculated in argons pumped by electron beam. The analytic formulas on differential ionization cross sections and excitation cross sections are selected for calculation. The calculated results, which include the stationary electron distribution and characteristic time for beams to reach the stationary distributions, are analyzed and
The basic Boltzmann equation in reference is improved. Compared with the basic equation, the improved Boltzmann equation can describe the collision between electron and fundamental state argon more perfectly, and can calculate the electron distribution in the whole energy range. With the basic Boltzmann equation and the improved Boltzmann equation, the high energy electron distributions, whose energy is larger than the first excited state energy (11.56eV), are calculated in argons pumped by electron beam. The analytic formulas on differential ionization cross sections and excitation cross sections are selected for calculation. The calculated results, which include the stationary electron distribution and characteristic time for beams to reach the stationary distributions, are analyzed and
2003,
15.
Abstract:
The green problem in intracavity frequencydoubled laser with folded resonator was studied based on the Jones matrix and coupling wave equation methods. The polarization effect of the folded mirror was discussed and its influence on the stability of green ouput was analyzed. The calculation results were compared with the experiments. It indicates that reasonably designed folded resonator can reduce the green fluctuation more effectively than the linear resonator．
The green problem in intracavity frequencydoubled laser with folded resonator was studied based on the Jones matrix and coupling wave equation methods. The polarization effect of the folded mirror was discussed and its influence on the stability of green ouput was analyzed. The calculation results were compared with the experiments. It indicates that reasonably designed folded resonator can reduce the green fluctuation more effectively than the linear resonator．
2003,
15.
Abstract:
The water vapor has great influence on the performance of a chemical oxygeniodine laser. The equations for the O2(1Δ) yield and steady onedimensional flow with area change are set up to take into account the quenching. The code is made to calculate the flow properties of the Radicl device. The effects of iodine dissociation and quenching on the flow properties of a chemical oxygeniodine laser are studied theoretically. The role of area change and the factors in its design are analyzed.
The water vapor has great influence on the performance of a chemical oxygeniodine laser. The equations for the O2(1Δ) yield and steady onedimensional flow with area change are set up to take into account the quenching. The code is made to calculate the flow properties of the Radicl device. The effects of iodine dissociation and quenching on the flow properties of a chemical oxygeniodine laser are studied theoretically. The role of area change and the factors in its design are analyzed.
2003,
15.
Abstract:
This paper introduces the method of guiding the six KrF laser beams into target chamber and the development of focus system in MOPA angular multiplex system for HeavenⅠ. The six beams are focused to the vacuum target chamber by six planeconvex lenses. The focal spot on the target is measured by UV CCD camera, the diameter of the focal spot of six beams is 290μm, the focusing power density on the target is 8×1012W/cm2.
This paper introduces the method of guiding the six KrF laser beams into target chamber and the development of focus system in MOPA angular multiplex system for HeavenⅠ. The six beams are focused to the vacuum target chamber by six planeconvex lenses. The focal spot on the target is measured by UV CCD camera, the diameter of the focal spot of six beams is 290μm, the focusing power density on the target is 8×1012W/cm2.
2003,
15.
Abstract:
In this paper, the precise design of the diffractive optical element (DOE) is completed for beam smoothing in Fresnel diffraction region. By using the hybrid algorithm, merging Hillclimbing with Simulated Annealing, true beam smoothing has been obtained, the intensity distribution of any point, besides the used sampling point in the optimization, on the output plane is consistent with the demand for beam smoothing. The phase depth of the designed DOE is smaller than π, which is very beneficial for the followup fabrication.
In this paper, the precise design of the diffractive optical element (DOE) is completed for beam smoothing in Fresnel diffraction region. By using the hybrid algorithm, merging Hillclimbing with Simulated Annealing, true beam smoothing has been obtained, the intensity distribution of any point, besides the used sampling point in the optimization, on the output plane is consistent with the demand for beam smoothing. The phase depth of the designed DOE is smaller than π, which is very beneficial for the followup fabrication.
2003,
15.
Abstract:
To specify the component focus performance the author uses the RMS gradient so that the direct relationship of the fabrication quality and the focus performance of the laser beam can be easily found. In this paper the definition of the RMS gradient and its characteristics are introduced, the differences between the RMS gradient and the PV, RMS，PSD are discussed. The RMS gradient analyzing results of some typical components employed in the high power laser system are presented. The results show that the RMS gradient is a kind of efficient tool to specify the optical components’ fabrication quality.
To specify the component focus performance the author uses the RMS gradient so that the direct relationship of the fabrication quality and the focus performance of the laser beam can be easily found. In this paper the definition of the RMS gradient and its characteristics are introduced, the differences between the RMS gradient and the PV, RMS，PSD are discussed. The RMS gradient analyzing results of some typical components employed in the high power laser system are presented. The results show that the RMS gradient is a kind of efficient tool to specify the optical components’ fabrication quality.
2003,
15.
Abstract:
This paper discusses the principle of imaging with circular interference fringes and the processing method with matched filter, it also calculated the point spread function. It gives two digital relations by simulation: between the mainside lobe ratio and the phase, and between the departure and the phase. The conclusion is that suitable departure helps to improve the resolution of the imaging, and not to bring any unreasonable side lobe that influences the point spread function.
This paper discusses the principle of imaging with circular interference fringes and the processing method with matched filter, it also calculated the point spread function. It gives two digital relations by simulation: between the mainside lobe ratio and the phase, and between the departure and the phase. The conclusion is that suitable departure helps to improve the resolution of the imaging, and not to bring any unreasonable side lobe that influences the point spread function.
2003,
15.
Abstract:
A numerical model of atmospheric optical refractive index structure parameter is presented. The input data for this model consisted of date，time，latitude and longitude，temperature，humidity，windspeed，roughness length，soil parameter，and cloud parameter,24h forecasts of the time variation of refractive index structure parameter near the surface will be produced. Comparison of measured and modeled results indicated that refractire index structure parameter both monthly and daily averaged can give consistent results. Comparison of total downward radiative flux modeled and measured is generally quite satisfactory．
A numerical model of atmospheric optical refractive index structure parameter is presented. The input data for this model consisted of date，time，latitude and longitude，temperature，humidity，windspeed，roughness length，soil parameter，and cloud parameter,24h forecasts of the time variation of refractive index structure parameter near the surface will be produced. Comparison of measured and modeled results indicated that refractire index structure parameter both monthly and daily averaged can give consistent results. Comparison of total downward radiative flux modeled and measured is generally quite satisfactory．
2003,
15.
Abstract:
One way to diagnose the target conditions during a laserdriven capsule implosion is to incorporate diagnostic dopant atoms in the capsule wall material-polystyrene (PS). In this paper two kinds of doping methods（chemical and physical） are discussed. conventionally,chemical synthesis route to produce polystyrene like polymers is possible.It is straightforward to covalently bond nonmetal dopants like bromine，iodine or other halogens onto plystyrene's pendant rings.Deuterated polystyrene with silicon dopant can also be produced. Metals,on the other hand,do not routinely be bonded covalently to nonmetallic atomic structures.Iron, chromium or titanium，however, can form a stable sandwich compound with a pair of cyclopentadienyl rings.As for the low producing rate and crosslinking of the
One way to diagnose the target conditions during a laserdriven capsule implosion is to incorporate diagnostic dopant atoms in the capsule wall material-polystyrene (PS). In this paper two kinds of doping methods（chemical and physical） are discussed. conventionally,chemical synthesis route to produce polystyrene like polymers is possible.It is straightforward to covalently bond nonmetal dopants like bromine，iodine or other halogens onto plystyrene's pendant rings.Deuterated polystyrene with silicon dopant can also be produced. Metals,on the other hand,do not routinely be bonded covalently to nonmetallic atomic structures.Iron, chromium or titanium，however, can form a stable sandwich compound with a pair of cyclopentadienyl rings.As for the low producing rate and crosslinking of the
2003,
15.
Abstract:
A compact Plasma Electrode Pockels Cell (PEPC) electrooptical switch will be used in beam reverser of multipass amplification system to control the output beam and restrain the selfoscillation produced by the multipass amplifier. In this paper, the performance of the compact PEPC electronoptical switch and its application in multipass amplification system are described in detail. Measurements of the optical performance show static transmittance of 94%, switching efficiency of 98.9%. The experimental result in multipass amplifier indicates that the PEPC electronoptical switch works well.
A compact Plasma Electrode Pockels Cell (PEPC) electrooptical switch will be used in beam reverser of multipass amplification system to control the output beam and restrain the selfoscillation produced by the multipass amplifier. In this paper, the performance of the compact PEPC electronoptical switch and its application in multipass amplification system are described in detail. Measurements of the optical performance show static transmittance of 94%, switching efficiency of 98.9%. The experimental result in multipass amplifier indicates that the PEPC electronoptical switch works well.
2003,
15.
Abstract:
Nelike Cr Ｘray laser was produced at low irradiance of pumping optical laser in XingguangII laser facility, and was used as probe laser of Moirefringe deflectometry device. The clear XRL Moirefringe without the object was obtained .The experimental method is described, the results are given and briefly discussed in the paper.
Nelike Cr Ｘray laser was produced at low irradiance of pumping optical laser in XingguangII laser facility, and was used as probe laser of Moirefringe deflectometry device. The clear XRL Moirefringe without the object was obtained .The experimental method is described, the results are given and briefly discussed in the paper.
2003,
15.
Abstract:
The crystallinity of PVA film under different annealing condition was measured by X-ray diffraction in this paper. The H2 barrier property of PVA film under different annealing condition was also studied in the hydrogen gas permeation system. Increasing annealing temperature can increase the crystallinity of PVA film, so the hydrogen barrier permeability of the annealed PVA film will be better. But the annealing temperature should be selected under 180℃ to prevent the PVA film from thermal degradation. On the other side, annealing the PVA film under its glass transition temperature will also improve the hydrogen barrier permeability of the PVA film. Lower alcoholysis degree of PVA films show better H2 barrier property improvement after they are annealed under glass transition temperature.
The crystallinity of PVA film under different annealing condition was measured by X-ray diffraction in this paper. The H2 barrier property of PVA film under different annealing condition was also studied in the hydrogen gas permeation system. Increasing annealing temperature can increase the crystallinity of PVA film, so the hydrogen barrier permeability of the annealed PVA film will be better. But the annealing temperature should be selected under 180℃ to prevent the PVA film from thermal degradation. On the other side, annealing the PVA film under its glass transition temperature will also improve the hydrogen barrier permeability of the PVA film. Lower alcoholysis degree of PVA films show better H2 barrier property improvement after they are annealed under glass transition temperature.
2003,
15.
Abstract:
The influence of the vacuum bake of plasma focus device before discharge experiment on stability and reliability of DPF has been discussed in this paper. The structure, mechanical design and the working principle of the doublevacuum bake device have also been introduced. As a result, the importance of doublevacuum bake of DPF device and the potential application have been shown according to the experimental data．
The influence of the vacuum bake of plasma focus device before discharge experiment on stability and reliability of DPF has been discussed in this paper. The structure, mechanical design and the working principle of the doublevacuum bake device have also been introduced. As a result, the importance of doublevacuum bake of DPF device and the potential application have been shown according to the experimental data．
2003,
15.
Abstract:
The sensitivity, linear absorption coefficient and derivation, repeatability for LiF thermoluminescence dosemeter (TLD) are measured using a standard γray source. A model is built to correct mass stopping power of the electron. The equivalent mass stopping power of the electron is calculated theoretically using the corrected model. The electron fluence can be obtained from the effective stopping power. An array of LiF TLD can be used to measure the hot electrons energy spectrum emitting from laserplasma.
The sensitivity, linear absorption coefficient and derivation, repeatability for LiF thermoluminescence dosemeter (TLD) are measured using a standard γray source. A model is built to correct mass stopping power of the electron. The equivalent mass stopping power of the electron is calculated theoretically using the corrected model. The electron fluence can be obtained from the effective stopping power. An array of LiF TLD can be used to measure the hot electrons energy spectrum emitting from laserplasma.
2003,
15.
Abstract:
Electronimpact excitation collision strengths among configurationaverage levels from Felike Au 53+ to Ge like Au 47+ ions have been calculated systematically based on Cowan's quasi relativistic multi configuration Hartree Fock Relativistic code and distorted wave approachs. The data for the collision strengths and thermally averaged rate coefficients over the whole range of energy or electron temperature have been evaluated by a leasesquares spline fitting procedure. The results indicate the error between our work and other theory is less then 10% in the diagnosed electron temperature about 2keV. It is feasible to simulate the average ionized state and ionic abundance and charge state distribution in a highly ionized Au plasma
Electronimpact excitation collision strengths among configurationaverage levels from Felike Au 53+ to Ge like Au 47+ ions have been calculated systematically based on Cowan's quasi relativistic multi configuration Hartree Fock Relativistic code and distorted wave approachs. The data for the collision strengths and thermally averaged rate coefficients over the whole range of energy or electron temperature have been evaluated by a leasesquares spline fitting procedure. The results indicate the error between our work and other theory is less then 10% in the diagnosed electron temperature about 2keV. It is feasible to simulate the average ionized state and ionic abundance and charge state distribution in a highly ionized Au plasma
2003,
15.
Abstract:
The phase II upgrading project of Hefei 800MeV electron storage ring is being done, and the important component of the project, the RF cavity, will be finished soon. The old RF cavity with many disadvantages will be replaced by the new one. To estimate the effect of RF cavity coupling impedance to storing bunch intensity fully, the wake potential and the broad band couple impedance of RF cavity were calculated with MAFIA program. And the calculation results were compared between new and old cavity, it is found that the impedance of the new is bigger than that of the old.
The phase II upgrading project of Hefei 800MeV electron storage ring is being done, and the important component of the project, the RF cavity, will be finished soon. The old RF cavity with many disadvantages will be replaced by the new one. To estimate the effect of RF cavity coupling impedance to storing bunch intensity fully, the wake potential and the broad band couple impedance of RF cavity were calculated with MAFIA program. And the calculation results were compared between new and old cavity, it is found that the impedance of the new is bigger than that of the old.
2003,
15.
Abstract:
A Nifilm bolometer driven by the pulsed constantvoltage supply was developed. The method of measuring the total soft Ｘray energy and the measuring system was presented. A Nifilm detector was developed and calibrated for the dependence with temperature . This bolometer has been applied in measuring the total soft Ｘray energy for the high power Zpinch plasma produced from QiangguangI accelerator. The uncertainty of the measurment was analyzed.
A Nifilm bolometer driven by the pulsed constantvoltage supply was developed. The method of measuring the total soft Ｘray energy and the measuring system was presented. A Nifilm detector was developed and calibrated for the dependence with temperature . This bolometer has been applied in measuring the total soft Ｘray energy for the high power Zpinch plasma produced from QiangguangI accelerator. The uncertainty of the measurment was analyzed.
2003,
15.
Abstract:
In this paper, a new ceramic surface flashover trigger of pseudospark switch is presented for the first time. Experiments demonstrate that this trigger has long lifetime and the triggered pseudospark switch provides an excellent delay of 50~340ns and jitter of 15~40ns at the discharge voltage of 30~2kV. The emitted plasma electron density is high enough to trigger switches reliably at a low voltage of 600V．
In this paper, a new ceramic surface flashover trigger of pseudospark switch is presented for the first time. Experiments demonstrate that this trigger has long lifetime and the triggered pseudospark switch provides an excellent delay of 50~340ns and jitter of 15~40ns at the discharge voltage of 30~2kV. The emitted plasma electron density is high enough to trigger switches reliably at a low voltage of 600V．
2003,
15.
Abstract:
Computer simulations are carried out for an RFQ in either 2-D coordinates (by SUPERFISH) or 3-D coordinates (by MAFIA), by which the RF field distribution of the operating mode is determined and the designing on the coupling cell is made. In the meantime, the tuners and the beginning cell of RFQ are also designed. The designing on the coupling cell must satisfy the condition that the RFQ is most insensitive to perturbations. To this end, the mode spacing of the two neighbour modes of the operating mode with respect to operating mode are chosen to be equal.
Computer simulations are carried out for an RFQ in either 2-D coordinates (by SUPERFISH) or 3-D coordinates (by MAFIA), by which the RF field distribution of the operating mode is determined and the designing on the coupling cell is made. In the meantime, the tuners and the beginning cell of RFQ are also designed. The designing on the coupling cell must satisfy the condition that the RFQ is most insensitive to perturbations. To this end, the mode spacing of the two neighbour modes of the operating mode with respect to operating mode are chosen to be equal.
2003,
15.
Abstract:
The photoinjected energy recovery LINAC (PERL) is a product of two basic techniques: the photoinjector and the superconducting energy recovery linac. Its major performances is to get the high brightness and high average power electron beams, operating for CW, and there are good application vistas in the high radiation field, include high average power FEL and new generation light sources. The photoinjector is the best source for the production of highbrightness electron beams. The superconducting energy recovery linac can deliver nonstored intensecurrent electron beams. This paper presents a preliminary study on the DC gun photoinjector and the superconducting cavity linac. When the DC high voltage is greater than or equal to 1MV and the accelerating field is greater than or
The photoinjected energy recovery LINAC (PERL) is a product of two basic techniques: the photoinjector and the superconducting energy recovery linac. Its major performances is to get the high brightness and high average power electron beams, operating for CW, and there are good application vistas in the high radiation field, include high average power FEL and new generation light sources. The photoinjector is the best source for the production of highbrightness electron beams. The superconducting energy recovery linac can deliver nonstored intensecurrent electron beams. This paper presents a preliminary study on the DC gun photoinjector and the superconducting cavity linac. When the DC high voltage is greater than or equal to 1MV and the accelerating field is greater than or
2003,
15.
Abstract:
Through the definition of the ratio of the LTD primary and secondary equivalent inductance to the stimulating inductance, a relationship of the stored energy per unit core volume to the circuit and core parameters and core magnetic induction increment is obtained. A method of judging whether the core is saturated and simulating the output performance of LTD is presented with the combination of PSPICE program and LTD equivalent circuit.
Through the definition of the ratio of the LTD primary and secondary equivalent inductance to the stimulating inductance, a relationship of the stored energy per unit core volume to the circuit and core parameters and core magnetic induction increment is obtained. A method of judging whether the core is saturated and simulating the output performance of LTD is presented with the combination of PSPICE program and LTD equivalent circuit.
2003,
15.
Abstract:
This paper presents a comprehensive theoretical treatment for dispersion relation of cylindercone diskloaded waveguide. The results of the numerical computation for various parameters of the devices are given, the TM mode is analyzed, and compared with the cylinder diskloaded waveguide. It can be operated on higher frequency with broad band than cylinder diskloaded waveguide.
This paper presents a comprehensive theoretical treatment for dispersion relation of cylindercone diskloaded waveguide. The results of the numerical computation for various parameters of the devices are given, the TM mode is analyzed, and compared with the cylinder diskloaded waveguide. It can be operated on higher frequency with broad band than cylinder diskloaded waveguide.
2003,
15.
Abstract:
This paper presents a calculation method of the mode coefficient (amplitude) on Vlasov radiator aperture by Method of Moments (MoM), and the reflective characteristics of bevel-cut radiator are studied through this method. The relations of the reflectivity to bevel-cut angle and diameter-wavelength ratio are obtained, which indicate that the reflectivity of the radiator is very small. The results are helpful for the design of the radiator.
This paper presents a calculation method of the mode coefficient (amplitude) on Vlasov radiator aperture by Method of Moments (MoM), and the reflective characteristics of bevel-cut radiator are studied through this method. The relations of the reflectivity to bevel-cut angle and diameter-wavelength ratio are obtained, which indicate that the reflectivity of the radiator is very small. The results are helpful for the design of the radiator.
2003,
15.
Abstract:
This paper presents the numerical simulation method by Finite Integration Method softwareMAFIA and Finite Element Method softwareANSYS to calculate Eigenvalue and Q value in two kinds of high frequency cavity. The simulation result are good consistency with part experiment data; The average calculation precise may be less than 5%. It proves that both electromagnetic software are capable of simulating eigenvalue problems in high frequency cavity, making some research for compute simulation to satisfy practical engineering design demand in computation precise. The calculation time is compared for the both software.
This paper presents the numerical simulation method by Finite Integration Method softwareMAFIA and Finite Element Method softwareANSYS to calculate Eigenvalue and Q value in two kinds of high frequency cavity. The simulation result are good consistency with part experiment data; The average calculation precise may be less than 5%. It proves that both electromagnetic software are capable of simulating eigenvalue problems in high frequency cavity, making some research for compute simulation to satisfy practical engineering design demand in computation precise. The calculation time is compared for the both software.
