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RSS1996 Vol. 08, No. 04
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1996,
08.
Abstract:
The electron back bombardment phenomenon in high accelerating gradient standing wave linear accelerators has been analysed in comparison with that in magnetrons and microwave thermionic guns. The methods of lowering the electron back bombardment power on the electron gun cathode and simultaneously increasing the accelerating gradient along the accelerating structure are introduced.
The electron back bombardment phenomenon in high accelerating gradient standing wave linear accelerators has been analysed in comparison with that in magnetrons and microwave thermionic guns. The methods of lowering the electron back bombardment power on the electron gun cathode and simultaneously increasing the accelerating gradient along the accelerating structure are introduced.
1996,
08.
Abstract:
In this paper, the transient temperature distribution and subsequent the thermal distortion resulting of coated non-cooled optical components irradiated by an annular high power continuous wave (CW) laser beam are studied in detail. The thermal distortion of various coated noncooled optical components subjected to CW-COIL laser irradiation is tested by using a Twyman –Green interferometer and compared with theoretical results. It is shown that the experimental results agree well with the theoretical analysis.
In this paper, the transient temperature distribution and subsequent the thermal distortion resulting of coated non-cooled optical components irradiated by an annular high power continuous wave (CW) laser beam are studied in detail. The thermal distortion of various coated noncooled optical components subjected to CW-COIL laser irradiation is tested by using a Twyman –Green interferometer and compared with theoretical results. It is shown that the experimental results agree well with the theoretical analysis.
1996,
08.
Abstract:
In this paper, the characteristics of stimulate Raman scattering pulse duration in He/H2 gas mixtures are investigated. The pulse duration of the first Stokes emission can be changed between 20~45ns by changing the ratio of He/H2 gas pressure with the 308nm pump pulse duration of 65ns. The effects of He on Raman gain in H2 is discussed to explain the experiments results.
In this paper, the characteristics of stimulate Raman scattering pulse duration in He/H2 gas mixtures are investigated. The pulse duration of the first Stokes emission can be changed between 20~45ns by changing the ratio of He/H2 gas pressure with the 308nm pump pulse duration of 65ns. The effects of He on Raman gain in H2 is discussed to explain the experiments results.
1996,
08.
Abstract:
This paper analyses the closed –loop noise, the error caused by turbulence and the total error of adaptive optics system in terms with servo control loop. Based on the total error, the effectiveness, the optimal closed –loop bandwidth selection and the limited capability of adaptive optics system are also analysed. Furthermore, the analytic result cuves of a practical system, the infrared adaptive optics system at 2.16m telescope, are presented in this paper.
This paper analyses the closed –loop noise, the error caused by turbulence and the total error of adaptive optics system in terms with servo control loop. Based on the total error, the effectiveness, the optimal closed –loop bandwidth selection and the limited capability of adaptive optics system are also analysed. Furthermore, the analytic result cuves of a practical system, the infrared adaptive optics system at 2.16m telescope, are presented in this paper.
1996,
08.
Abstract:
Based upon the multiphase amplification theory, this paper presents the calculation and analysis on regenerative amplifiers. Experimental results and discussion for the chirpedpulse amplification of femtosecond Ti: sapphire laser pulses with mJ output energy and over 106 total gain are also included.
Based upon the multiphase amplification theory, this paper presents the calculation and analysis on regenerative amplifiers. Experimental results and discussion for the chirpedpulse amplification of femtosecond Ti: sapphire laser pulses with mJ output energy and over 106 total gain are also included.
1996,
08.
Abstract:
FEL small signal gain theory for transverse optical klystron has been derived in this paper using FEL longitudinal –mode –unified –theory, and the effects of compactor parameter Nd, as well as electron beam energy spread and emittance are analyzed.
FEL small signal gain theory for transverse optical klystron has been derived in this paper using FEL longitudinal –mode –unified –theory, and the effects of compactor parameter Nd, as well as electron beam energy spread and emittance are analyzed.
1996,
08.
Abstract:
Frequency characteristics for plasma-filled relativistic backward-wave oscillator are studied in this paper, as a result, oscillation frequency of RBWO up shifts as the density of background plasma increases. The results of experiment are in agree with the results of theory for the case of empty waveguide.
Frequency characteristics for plasma-filled relativistic backward-wave oscillator are studied in this paper, as a result, oscillation frequency of RBWO up shifts as the density of background plasma increases. The results of experiment are in agree with the results of theory for the case of empty waveguide.
1996,
08.
Abstract:
This paper describes a box calorimeter used in measuring scattered light and absorption. The performance test has shown that this box calorimeter is better in sensitivity, time response and ability to resist interference than the box calorimeter used in LLNL.
This paper describes a box calorimeter used in measuring scattered light and absorption. The performance test has shown that this box calorimeter is better in sensitivity, time response and ability to resist interference than the box calorimeter used in LLNL.
1996,
08.
Abstract:
In this paper the experimental results of laser arrays are reported for trigger photoconductive semiconductor switch array in the electromagnetic pulse generator. The GaAs laser arrays output with full width at half maximum of 0.7~5ns and the beam’s area of about 100mm 6mm. The effective repetition rate of double peak –pulse serials is about 100MHz. The superposition method of multi –beam is described.
In this paper the experimental results of laser arrays are reported for trigger photoconductive semiconductor switch array in the electromagnetic pulse generator. The GaAs laser arrays output with full width at half maximum of 0.7~5ns and the beam’s area of about 100mm 6mm. The effective repetition rate of double peak –pulse serials is about 100MHz. The superposition method of multi –beam is described.
1996,
08.
Abstract:
In this article, we investigate numerically the nonlinear scatter of intense laser pulses with different frequency and intensity by the electron bound in one –dimensional potential with different deepth and width. Two facts are found: (1) For the given laser pulse, the tighter the potential bound the electron, the difficulter scattering harmonics extends to high order; (2) For the same potential and two laser pulses with identical intensity, the high frequency laser is easier to generate harmonics than the low frequency laser, but the harmonic order number is not higher.
In this article, we investigate numerically the nonlinear scatter of intense laser pulses with different frequency and intensity by the electron bound in one –dimensional potential with different deepth and width. Two facts are found: (1) For the given laser pulse, the tighter the potential bound the electron, the difficulter scattering harmonics extends to high order; (2) For the same potential and two laser pulses with identical intensity, the high frequency laser is easier to generate harmonics than the low frequency laser, but the harmonic order number is not higher.
1996,
08.
Abstract:
An analytical model for laser –induced heating, heat conduction and thermal stress crack of a brittle thin target is proposed. The analytical expressions are induced for the temperature increment and thermal stress that varies with time, which can be described as h I0b2/Kh and a Eh I0b2/Kh , respectively, while their space –time distributions being expressed as a infinite series. The threshold laser parameters for thermal stress crack of K9 glass and MgF2 ploycrystal targets predicted by this model are in agreement with those obtained experimentally.
An analytical model for laser –induced heating, heat conduction and thermal stress crack of a brittle thin target is proposed. The analytical expressions are induced for the temperature increment and thermal stress that varies with time, which can be described as h I0b2/Kh and a Eh I0b2/Kh , respectively, while their space –time distributions being expressed as a infinite series. The threshold laser parameters for thermal stress crack of K9 glass and MgF2 ploycrystal targets predicted by this model are in agreement with those obtained experimentally.
1996,
08.
Abstract:
In a solenoidel focusing field, the centroid of any slice in an electron beam will execute cyclotron oscillation, if the magnetic –axis is tilted from the axis of accelerator. The energy variation within the beam pulse will make cyclotron oscillation develope corkscrew oscillation. In this paper, the trajectory of beam centroid is analytically found, the expression of the effective radius for an electron beam is given, and the method to reduce corkscrew oscillation is simply discussed.
In a solenoidel focusing field, the centroid of any slice in an electron beam will execute cyclotron oscillation, if the magnetic –axis is tilted from the axis of accelerator. The energy variation within the beam pulse will make cyclotron oscillation develope corkscrew oscillation. In this paper, the trajectory of beam centroid is analytically found, the expression of the effective radius for an electron beam is given, and the method to reduce corkscrew oscillation is simply discussed.
1996,
08.
Abstract:
A new suggestion that there is a phase jump of p in the boundary wave is put forward in this paper. This suggestion may be a supplement of Huygens –Fresnel principle. Based on this new suggestion, a series of new beam was invented, both outside and inside laser cavity. Especially, a new CO2 laser with equivalent beam quality factor Me2 <1 is achieved. It can be considered as the result of some controllable nonlinear self –focusing.
A new suggestion that there is a phase jump of p in the boundary wave is put forward in this paper. This suggestion may be a supplement of Huygens –Fresnel principle. Based on this new suggestion, a series of new beam was invented, both outside and inside laser cavity. Especially, a new CO2 laser with equivalent beam quality factor Me2 <1 is achieved. It can be considered as the result of some controllable nonlinear self –focusing.
1996,
08.
Abstract:
In the paper, the importance of the beam propagation equation in ISO standard draft is discussed, and a verifying method is given. The beam propagation equation is applied to not only Gaussian beam but also the other non –Gaussian beam on the paraxial condition, and it lays the foundation for Gaussian beam to become the measured standard of beam quality.
In the paper, the importance of the beam propagation equation in ISO standard draft is discussed, and a verifying method is given. The beam propagation equation is applied to not only Gaussian beam but also the other non –Gaussian beam on the paraxial condition, and it lays the foundation for Gaussian beam to become the measured standard of beam quality.
1996,
08.
Abstract:
A compact subsonic CW chemical oxygen –iodine laser (COIL) was firstly used as a probe to measure the temporal and spatial dependence of the small –signal gain in a supersonic CW COIL. The results are discussed.
A compact subsonic CW chemical oxygen –iodine laser (COIL) was firstly used as a probe to measure the temporal and spatial dependence of the small –signal gain in a supersonic CW COIL. The results are discussed.
1996,
08.
Abstract:
The surface perturbation target is one of the most important experimental targets for the resolved experiments of inertial-confinement fusion (ICF). In this paper, we report the preparation of the sine modulated perturbation figures with perturbation amplitude and wavelength of about several and tens of micron respectively with the methods of ion-beam etching and laser interference. The perturbation profiles of the figures were investigated by an alpha –step device and an optical microscopic profiler. Different technological conditions, preparation process and their relationship with the quality of the figures were studied.
The surface perturbation target is one of the most important experimental targets for the resolved experiments of inertial-confinement fusion (ICF). In this paper, we report the preparation of the sine modulated perturbation figures with perturbation amplitude and wavelength of about several and tens of micron respectively with the methods of ion-beam etching and laser interference. The perturbation profiles of the figures were investigated by an alpha –step device and an optical microscopic profiler. Different technological conditions, preparation process and their relationship with the quality of the figures were studied.
1996,
08.
Abstract:
Using a metal-ceramic triode as the H. V. Pulse generator, a high operating frequency and long lifetime driver for electro-optic Q –switches was designed. The driver can work at 1kHz. The amplitude of the output pulse is 2.5~8kV and the risetime is shorter than 25ns.
Using a metal-ceramic triode as the H. V. Pulse generator, a high operating frequency and long lifetime driver for electro-optic Q –switches was designed. The driver can work at 1kHz. The amplitude of the output pulse is 2.5~8kV and the risetime is shorter than 25ns.
1996,
08.
Abstract:
This paper presents results obtained during experiment research on the insulation recovery of the rep-rate gas spark gap. Insulation recovery information has generally been obtained using a two –pulse technique while the nanoseconds pulse breaks down the gap. First, under static conditions (unblown), hydrogen gas allows an order –of –magnitude improvement in the recovery of an unblow spark gap. Under dynamic conditions (gas flow), gas between the electrodes allow a significant improvement in the switch recovery.
This paper presents results obtained during experiment research on the insulation recovery of the rep-rate gas spark gap. Insulation recovery information has generally been obtained using a two –pulse technique while the nanoseconds pulse breaks down the gap. First, under static conditions (unblown), hydrogen gas allows an order –of –magnitude improvement in the recovery of an unblow spark gap. Under dynamic conditions (gas flow), gas between the electrodes allow a significant improvement in the switch recovery.
1996,
08.
Abstract:
Using the calculation way suggested by P. H. Hu et al. We solve the zeroth –order equations suggested by A. Flusberg et al in numerical method. We calculate the Stokes intensity, the pump intensity, and the fidelity that vary with the positions in the Brillouin cell, and obtain the transverse distributions for the Stokes phase and intensity at several positions in the Brillouin cell, and calculate the reflectivety and fidelity at the pump entrance that vary with the gain G =gIp0L.
Using the calculation way suggested by P. H. Hu et al. We solve the zeroth –order equations suggested by A. Flusberg et al in numerical method. We calculate the Stokes intensity, the pump intensity, and the fidelity that vary with the positions in the Brillouin cell, and obtain the transverse distributions for the Stokes phase and intensity at several positions in the Brillouin cell, and calculate the reflectivety and fidelity at the pump entrance that vary with the gain G =gIp0L.
1996,
08.
Abstract:
A type of voltage controlled phase shifter developed by HIRFL laboratory is better than mechanical phase shifter in all respects of performance, price, and reliability. It’s principle is based on vector composition, so this new phase shifter is called vector resultant voltage controlled phase shifter. This new phase shifter has been applied in HIRFL phase stabilization system and satisfactory result has been obtained.
A type of voltage controlled phase shifter developed by HIRFL laboratory is better than mechanical phase shifter in all respects of performance, price, and reliability. It’s principle is based on vector composition, so this new phase shifter is called vector resultant voltage controlled phase shifter. This new phase shifter has been applied in HIRFL phase stabilization system and satisfactory result has been obtained.
1996,
08.
Abstract:
In this paper, we suggest a new hybrid wiggles with six lagers and side –blocks which has two direction focusing function, and simulate the magnetic field of the new hybrid wiggles. Under the limitation g/l w =3, the peak magnetic field of new hybrid wiggles is in excess of 1T.
In this paper, we suggest a new hybrid wiggles with six lagers and side –blocks which has two direction focusing function, and simulate the magnetic field of the new hybrid wiggles. Under the limitation g/l w =3, the peak magnetic field of new hybrid wiggles is in excess of 1T.
1996,
08.
Abstract:
This paper describes the design, manufacture and experimental results of a rectangular magnetic coil, which was used in the experiment of excimer laser. The interior dimension of the coil is 925 425 100mm3. With the use of the coil a magnetic field of 0.225T (in the laser cavity) was achieved. The uniformity of electron beam was obviously improved by the magnetic field produced by the coil.
This paper describes the design, manufacture and experimental results of a rectangular magnetic coil, which was used in the experiment of excimer laser. The interior dimension of the coil is 925 425 100mm3. With the use of the coil a magnetic field of 0.225T (in the laser cavity) was achieved. The uniformity of electron beam was obviously improved by the magnetic field produced by the coil.
1996,
08.
Abstract:
Based on the HFR method for bound states and Distorted –Wave method for continuous states, photoionization cross sections that describe level to level transitions of He-like Rb and He –like Nb ions have been calculated. In the calculation, configuration interactions between bound states have been considered. The included configurations of the process are 1s nl 1s e l± 1(1 n 6, 0 n-1), and the energy range of free electron is 0 ~10 times the ionization energy. The computational error and the data accuracy are discussed. Also the results that have been summed over final states are provided.
Based on the HFR method for bound states and Distorted –Wave method for continuous states, photoionization cross sections that describe level to level transitions of He-like Rb and He –like Nb ions have been calculated. In the calculation, configuration interactions between bound states have been considered. The included configurations of the process are 1s nl 1s e l± 1(1 n 6, 0 n-1), and the energy range of free electron is 0 ~10 times the ionization energy. The computational error and the data accuracy are discussed. Also the results that have been summed over final states are provided.
1996,
08.
Abstract:
The monochromatic X –ray source was obtained using multilayer mirror on the BEPC –SR. The Sensitivity of X –ray diodes (XRD) and thickness of filters were calibrated using AXUV-100 silicon photodetector as the secondary standard. The experimental results of XRD sensitivity are consistent with LLNL experimental results.
The monochromatic X –ray source was obtained using multilayer mirror on the BEPC –SR. The Sensitivity of X –ray diodes (XRD) and thickness of filters were calibrated using AXUV-100 silicon photodetector as the secondary standard. The experimental results of XRD sensitivity are consistent with LLNL experimental results.
1996,
08.
Abstract:
In this paper, the analytical expression of the breakdown threshold power of HPM pulse propagation in atmosphere are derived approximatelly the sneak –through time of microwave pulse propagation through the atmosphere from ground to space are calculated and its physical picture and the variety of the sneak –through time are simulated numerically.
In this paper, the analytical expression of the breakdown threshold power of HPM pulse propagation in atmosphere are derived approximatelly the sneak –through time of microwave pulse propagation through the atmosphere from ground to space are calculated and its physical picture and the variety of the sneak –through time are simulated numerically.
1996,
08.
Abstract:
In this paper, the properties of laser propagation in media are have studied. Numerical solution shows that in media with quadratic or higher equivalent complex indexofrefraction n =n0+n2rm /rem , optical guiding will occure when laser propagates over. A certain distance. Whether considering saturation effect or not, we have got the similar results. Laser propagation parameters w, R-1 are dependent on n2 if we don’t consider saturation effect. Both the index of refraction and the gain make contributions to the emergence of optical guiding in media.
In this paper, the properties of laser propagation in media are have studied. Numerical solution shows that in media with quadratic or higher equivalent complex indexofrefraction n =n0+n2rm /rem , optical guiding will occure when laser propagates over. A certain distance. Whether considering saturation effect or not, we have got the similar results. Laser propagation parameters w, R-1 are dependent on n2 if we don’t consider saturation effect. Both the index of refraction and the gain make contributions to the emergence of optical guiding in media.
1996,
08.
Abstract:
Based on the general coupled wave equations in corrugated circular waveguides with axial curvature, this paper employs a numerical optimization method to get the design of 8mm TE01-HE11 high efficiency mode converter. Some factors such as the ohmic losses of the waveguide wall and the phase rematch techniques are taken into account. Finally, a set of optimized size and its calculation results are given.
Based on the general coupled wave equations in corrugated circular waveguides with axial curvature, this paper employs a numerical optimization method to get the design of 8mm TE01-HE11 high efficiency mode converter. Some factors such as the ohmic losses of the waveguide wall and the phase rematch techniques are taken into account. Finally, a set of optimized size and its calculation results are given.
