JP3633904B2 - X-ray generation method and X-ray generation apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an X-ray generation method and apparatus for generating X-rays by irradiating a laser beam onto a target, and in particular, an X-ray generation method for generating X-rays having a specific wavelength using a high-power ultrashort optical pulse laser and Relates to the device.
[0002]
[Prior art]
When high intensity laser light is irradiated onto the metal surface, X-rays with high luminance are generated from the plasma formed on the metal surface. In particular, by using an ultrashort pulse laser beam, X-rays with extremely high luminance can be obtained with relatively low energy.
In an X-ray generator that emits X-rays by irradiating a target with an ultrashort optical pulse laser, the X-ray output is very different from the material and shape of the target, the wavelength of the laser beam, the spatial intensity distribution, and the time waveform. It depends on many parameters.
[0003]
However, the conventional X-ray output control uses a method by adjusting the total intensity of the laser beam, that is, the energy intensity as an integral value over the entire wavelength, or adjusting the pulse interval when using a pulse laser. It was difficult to precisely control the output.
Conventionally, the energy intensity of the laser pulse X-ray is adjusted by shifting the focal point of the laser beam condensing system. However, the spatial intensity distribution of the laser itself cannot be changed. I couldn't make adjustments.
[0004]
For example, Japanese Patent Laid-Open No. 9-184900 discloses a pulse X-ray irradiation apparatus that measures the intensity of generated X-rays and adjusts the intensity of the last pulse laser shot so that the X-ray exposure amount matches a set value. Is disclosed. The beam intensity is adjusted by a method such as using a transmittance variable filter provided in the optical path or a time difference between the Q switch operation start signal and the laser medium excitation start signal in the Q switch laser device. According to this apparatus, even if the output of the pulse X-ray source fluctuates for each shot, the set X-ray dose and the integrated X-ray dose can be matched.
[0005]
In addition, it is possible to efficiently generate pulsed laser X-rays by first irradiating a target with a preliminary laser pulse to generate plasma, and then irradiating a main pulse to emit predetermined X-rays from the plasma. It is known that
Conventionally, as a method of obtaining a time waveform of a laser beam used for such a purpose, there has been a method of electrically controlling the amount of light of an excitation flash lamp such as pulse modulation. However, this method is limited in forming an ms level pulse interval, and in particular, the time waveform of an ultrashort optical pulse laser from ps to fs level cannot be controlled.
[0006]
As an object for ultrashort laser pulses, Japanese Patent Application Laid-Open No. 8-213192 divides a laser beam into a main pulse and a subpulse by a beam splitter, delays the main pulse through a delay circuit, and advances the subpulse. There has been disclosed a laser plasma X-ray generator that modulates an X-ray dose by delay time control by irradiating a metal target before a main pulse (delay pulse) to generate a preliminary plasma. In this disclosed apparatus, the entire input laser beam is divided into two by a beam splitter, and the two laser beams are transmitted through different laser path lengths so that one is delayed with respect to the other. A laser beam having a waveform is formed to control the amount of X-ray generation.
[0007]
[Problems to be solved by the invention]
However, when using the action of X-rays, it is not just a matter of the overall energy, but at a specific wavelength such as absorption reaction of chemical substances and biological substances, production of integrated circuits using single-wavelength X-rays, etc. X-ray effects are often of significant interest.
However, a simple method for controlling the intensity of a specific spectral line has not yet been developed.
Accordingly, the problem to be solved by the present invention is an apparatus for generating X-rays by irradiating a target with a high-intensity laser beam such as an ultrashort optical pulse laser, and the X-ray intensity, particularly a specific wavelength required. It is to provide an X-ray generation apparatus having a mechanism for adjusting a pulse laser so as to selectively control the X-ray intensity.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the X-ray generation method of the present invention applied to an X-ray generation apparatus that generates X-rays by irradiating a target with laser light has a laser beam spectrum perpendicular to the optical axis in a transmission path. The spatial phase distribution is adjusted by changing the effective optical path length for each part of the light beam that spreads in the direction and forms the Fourier plane, and then converges again to be focused on the target. The pulse time waveform of the laser beam at the focusing position is adjusted to a predetermined pattern, the intensity characteristics of the generated X-rays are measured, and the X-ray intensity is appropriate based on the measurement result of the X-ray intensity characteristics The pulse time waveform of the laser beam is adjusted so as to be.
[0009]
According to the X-ray generation method of the present invention, a light beam (Fourier plane) whose spectrum spreads in a direction perpendicular to the optical axis by using a spectrum resolving optical element such as a diffraction grating or a prism in one pulse laser is used. Since the spatial phase distribution of the laser beam is adjusted by adjusting the optical path length to be different for each part, the laser beam that converges again and irradiates the target surface has a time waveform having a peak at an appropriate position. Can be. Therefore, the X-ray generation is controlled by measuring the characteristics of the generated X-rays and feeding back the measurement results to the spatial intensity distribution pattern of the laser beam, so that the target characteristics take an optimum value. X-rays can be generated efficiently.
[0010]
The state of adjustment of the spatial intensity distribution of the laser beam is confirmed by monitoring the wavefront state of the laser beam in the transmission optical system, and parameters related to the spatial intensity distribution are appropriately adjusted to optimize the X-ray. It is preferable to do. There is no way to directly know the spatial intensity distribution of the laser beam at the target position, but a part of the transmission beam is split by a beam splitter, and the spatial intensity distribution at the target position is estimated from the focused pattern (far field pattern) This is because the adjustment result can be estimated from the wavefront state of the laser beam, and when the parameters that affect the spatial intensity distribution pattern are adjusted by directly knowing the wavefront state of the laser beam, the result can be accurately grasped. Because it can be done.
[0011]
The wavelength characteristic may be measured as the X-ray intensity characteristic, and the wavefront state of the laser beam may be adjusted based on the measured value of the X-ray intensity at the target specific wavelength. It is preferable that the X-rays to be generated have an intensity of a predetermined wavelength component determined depending on the purpose. If the wavelength characteristic of X-rays can be measured, the X-ray intensity at the target wavelength can be measured, and the spatial intensity distribution can be adjusted so that the intensity increases.
[0012]
The method of the present invention can also be applied when X-rays are generated using an ultrashort optical pulse laser having a pulse width of only picoseconds to femtoseconds. When an ultrashort light pulse laser is used, energy of extremely high intensity can be applied for a short time, and thus the target material can be efficiently converted into plasma and efficient X-ray generation can be achieved. In addition, since the ultrashort optical pulse laser has a wide spectral characteristic, the spatial phase distribution change mechanism works effectively.
[0013]
Here, it is preferable that the time waveform of the laser beam at the position focused on the target has several peaks, and in particular, there are two peaks, and the peak preceding in time preheats the target to generate plasma. When the X-ray is emitted by heating the plasma at the subsequent peak and the X-ray is emitted, the preceding pulse generates plasma on the target surface in advance, thereby increasing the absorption rate of the subsequent main pulse, and generating a predetermined X-ray. Since the time for maintaining the temperature state to be generated is lengthened, X-rays having characteristics corresponding to the plasma energy can be generated efficiently.
[0014]
Since the intensity ratio of two peaks and the time interval have a large correlation with the amount of X-ray generation, the amount of X-ray generation can be controlled by adjusting the spatial phase distribution state of the laser beam using these as parameters. .
In this way, the X-ray intensity at a predetermined wavelength is measured by measuring the wavelength characteristic of the X-ray generated from the target in accordance with the correlation between the generated X-ray and the laser beam characteristic and feeding it back to the spatial phase distribution change mechanism. Can be controlled automatically.
[0015]
In order to solve the above problems, an X-ray generator of the present invention includes a mechanism for expanding a laser beam spectrum in a direction perpendicular to the optical axis in a laser beam transmission optical system, and a spatial phase distribution adjusting mechanism for the laser beam. A laser beam converging mechanism is provided, and an X-ray measuring device for measuring the intensity of generated X-rays is arranged at the target portion. The X-ray measuring device measures the X-ray intensity, and the spatial phase is determined based on the measurement result. By adjusting the effective optical path length for each spectrum of the laser beam by the distribution adjustment mechanism, the pulse time waveform of the laser beam at the position focused on the target becomes a predetermined pattern having a plurality of peaks, and the X-ray intensity It adjusts so that may become appropriate.
[0016]
The X-ray generator of the present invention adjusts the wavefront state of the laser beam so as to obtain a time waveform at the target position that is estimated and obtained based on the result of measuring the X-ray characteristics. The optimum state can be controlled as desired.
Furthermore, in the X-ray generator of the present invention, a measuring device for measuring the time waveform of the laser beam is provided in the laser beam transmission optical system, and the laser beam wavefront state is monitored to measure the laser beam of the spatial phase distribution adjusting mechanism. It is preferable to optimize the adjustment method.
[0017]
Note that the laser beam used may be an ultrashort optical pulse laser.
The mechanism for expanding the spectrum of the laser beam can be constituted by a pulse stretcher or a pulse compressor used for the chirp amplification mechanism of the ultrashort optical pulse laser.
Furthermore, the X-ray measurement apparatus measures wavelength characteristics, and is preferably configured to adjust the spatial phase distribution adjustment mechanism based on the laser intensity at a specific wavelength extracted from the measurement result. By measuring the wavelength characteristics of X-rays, X-rays having a specific wavelength required for the X-ray generator can be selectively controlled.
[0018]
Note that the time waveform of the laser at the target position can be obtained by changing the optical path length of the reflected laser beam by locally forming irregularities on the surface of the reflection position using a spatial phase distribution change mechanism using a deformable mirror, for example. Can be adjusted. The 1 mm irregularity on the deformable mirror surface corresponds to a change in optical path length that produces a time change of about 3 ps. Since the influence on the X-ray intensity is observed from a time interval of several fs, the use of a deformable mirror provides a sufficient effect.
[0019]
In addition, the spatial phase change mechanism can be configured using a light transmitting material that can locally change the refractive index, such as a liquid crystal or an acoustooptic device.
The time waveform of the laser beam at the position focused on the target has two peaks in particular, and the amount of X-rays generated at a specific wavelength can be controlled by adjusting the peak intensity ratio or peak interval. it can.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to examples.
FIG. 1 is a block diagram showing the configuration of the X-ray generator of this embodiment, FIG. 2 is a conceptual diagram showing an example of a spatial phase distribution adjusting mechanism used in this embodiment, and FIG. 5 is a time waveform of a laser beam at a focusing position. Drawing which shows an example, FIG. 4 is the flowchart which showed the flow of control in the apparatus of a present Example, FIG. 5 is the conceptual diagram which shows another example of the spatial phase distribution adjustment mechanism used for a present Example.
[0021]
As shown in FIG. 1, the X-ray generator of this embodiment includes an ultrashort optical pulse laser generator 1, a spatial phase distribution adjusting mechanism 3, a reflecting mirror 4, a lens 6, and a target 7 set in a vacuum container 9. , An X-ray spectrometer 10, a waveform measuring instrument 12, a data processing device 13, and a control device 14.
After adjusting the wavefront phase distribution of the laser beam 2 generated by the ultrashort optical pulse laser generator 1 by the spatial phase distribution adjusting mechanism 3, the laser beam 2 is introduced into the lens 6 by the reflecting mirror 4 and applied to the target 7 set in the vacuum container 9. The X-ray 8 is generated from the generated plasma by condensing.
[0022]
The vacuum vessel 9 is provided with an X-ray spectrometer 10 so as not to obstruct the use of X-rays, and the X-ray intensity wavelength distribution of the generated X-rays 8 is measured.
The reflecting mirror 4 has a property of transmitting a part of the laser beam, and the transmitted laser 11 is incident on a waveform measuring instrument 12 that measures a temporal change in light intensity of the laser beam.
[0023]
The spatial phase distribution adjustment mechanism 3 expands the laser beam in space to partially change the effective optical path length and adjusts the time waveform to a predetermined pattern.
The spatial phase distribution adjusting mechanism 3 shown in FIG. 2 has two convex lenses (collimation lenses) or concave mirrors 33 and 34 arranged between a pair of diffraction gratings 31 and 32, and a spatial frequency filter in the middle of the convex lens or concave mirror. A transmissive optical element 35 such as a liquid crystal is inserted.
When the incident ultrashort optical pulse laser is guided to the diffraction grating 31 by the reflecting mirror 36 and the beam transformed by the diffraction grating 31 is converted into a parallel light flux by the convex lens 33, the wavelength component is developed according to the wavelength in the direction perpendicular to the optical axis. A so-called Fourier plane is formed in which are spatially distributed.
[0024]
The transmissive optical element 35 inserted in the Fourier plane adjusts the spatial phase distribution by changing the refractive index and changing the effective optical path length for each portion of the Fourier plane. For example, since the crystal state of the liquid crystal changes continuously by the applied electric field, the light refractive index can be adjusted for each portion of the light transmission surface by adjusting the applied voltage for each section.
When the spatial phase distribution adjusting mechanism 3 gives a difference in the passing time for each part by, for example, reducing the refractive index on the long wavelength side and increasing the refractive index on the short wavelength side according to the control signal given from the control device 14, The laser beam is split in time, with some energy leading and some energy delayed.
[0025]
This light beam is converged on the diffraction grating surface by a convex lens, synthesized again into a thin laser beam, emitted by the reflecting mirror on the same optical axis as the incident beam, and condensed on the target 7 by the converging lens 6.
As shown in FIG. 3, the time waveform of the laser beam at the condensing position is composed of a preceding pulse having a light intensity value Ps and a main pulse having a light intensity value Pm delayed by time b with respect to the preceding pulse.
[0026]
The preceding pulse generates plasma on the surface of the target 7 and improves the energy absorption efficiency of the main pulse. Further, when the energy of the ultrashort optical pulse laser for one shot does not change, the time for maintaining an appropriate plasma temperature can be made longer by adjusting the energy distributed to the preceding pulse and the main pulse. Also, the time interval b between both pulses affects the amount of X-ray generation.
Therefore, based on the result of measuring the wavelength characteristic of the X-ray generated by the X-ray spectrometer 10 and calculating the intensity of the X-ray having the wavelength required by the data processing device 13, the control device 14 uses the light intensity of the preceding pulse. By adjusting the ratio between the value Ps and the light intensity value Pm of the main pulse and the pulse time interval b, the wavelength component and intensity of the X-ray can be automatically controlled.
[0027]
A control procedure in the X-ray generator of the present embodiment is schematically shown in FIG.
The X-ray spectrometer 10 measures the X-ray intensity wavelength distribution of the generated X-ray 8, and the measurement result is transmitted to the data processing device 13 (S1). The data processing device 13 evaluates the X-ray spectrum corresponding to the purpose such as the intensity at a predetermined wavelength based on the measurement result of the X-ray intensity distribution (S2). Further, the amount of control parameter to be changed is calculated based on the evaluation result, and an instruction signal is supplied to the control device 14 (S3), and the control device 14 transmits a transmissive optical element such as liquid crystal in the spatial phase distribution adjusting mechanism 3. 35 is operated to change the optical path length for each portion of the Fourier plane and adjust the phase of the laser beam wave (S4), thereby adjusting the time waveform on the surface of the target 7 where the laser beam is focused, The wavelength distribution of X-rays emitted from the plasma generated in the above is made to have a desirable pattern.
[0028]
Further, the waveform measuring instrument 12 measures the result of adjusting the time waveform of the laser beam with the optical element 35, and gives the measurement result to the data processing device 13 (S5).
The data processing device 13 determines an appropriate time waveform of the laser beam in order to obtain a necessary X-ray characteristic by comparing the measurement result of the X-ray spectrum and the time waveform measurement result of the laser beam. An instruction signal for the control device 14 is generated (S6).
[0029]
In the laser plasma X-ray generator of this embodiment, the effective optical path length is changed for each portion of the laser beam whose frequency is expanded in the Fourier plane, and when the laser beam is refocused, the time waveform of the laser beam becomes the preceding pulse and the main pulse. In order to generate X-rays efficiently by generating plasma in advance on the target. In addition, the light intensity ratio and time interval between the leading pulse and main pulse that govern the X-ray characteristics and generation amount can be easily adjusted, so that the X-ray spectrometer automatically feeds back the measurement results and outputs X-rays automatically. Control can be performed.
[0030]
Therefore, for example, the X-ray intensity at a specific wavelength required for using X-rays can be detected and adjusted so as to maximize it.
The state adjusted by the spatial phase distribution adjusting mechanism 3 can be confirmed by the waveform measuring instrument 12. The measurement result of the time waveform of the laser beam is used for analyzing the relationship with the X-ray intensity and optimizing the pulse time interval and the pulse intensity ratio.
Furthermore, it is possible to automatically search for an optimum pulse intensity ratio by using, for example, a control system that sequentially scans using the pulse time interval as a parameter.
[0031]
It should be noted that the X-ray generator of this embodiment adjusts the target X-ray intensity by optimizing the spatial intensity distribution of the laser focused beam in the same procedure even if the target material, shape, or surface processing state is different. It can be carried out.
In this embodiment, the ultrashort optical pulse laser is used, but it goes without saying that the same mechanism can be applied even when other laser light is used.
Furthermore, in the description of the present embodiment, the spatial phase distribution is adjusted by expanding the laser beam on the Fourier plane using a diffraction grating. However, the spatial phase distribution may be adjusted simply for a widened beam.
[0032]
FIG. 5 is a block diagram illustrating an example of the spatial phase distribution adjusting mechanism 3 using a reflective optical system including a deformable mirror instead of the transmissive optical element in the present embodiment.
For example, the deformable mirror has an array of stacked piezo elements arranged on the back of a thin quartz plate with a reflective coating and adjusts the voltage applied to each piezo element to make the mirror surface optional using the electrostrictive effect. It is made to deform | transform into. There are other deformable mirrors such as bimorph type and membrane type.
The time for reaching the target can be adjusted by changing the effective optical path length by adjusting the unevenness of the reflecting surface.
When the reflection optical system is used, a laser beam with higher energy can be handled.
[0033]
In the spatial phase distribution adjusting mechanism 3 using a deformable mirror, as shown in the figure, the ultrashort optical pulse laser is introduced into the diffraction grating 41 by the reflecting mirror 46 and frequency-resolved by the convex lens 43 in the direction perpendicular to the optical axis. A parallel light beam is incident on the deformable mirror 45.
The surface shape of the deformable mirror 45 is arbitrarily adjusted for each part by the control device 14, and is formed into, for example, a stepped shape in which the left part in the figure protrudes and the right part retreats. The unevenness of 1 mm on the surface of the deformable mirror corresponds to an optical path length change that creates a time change of about 6 ps.
The parallel light beam reflected by the deformable mirror 45 is converged on the diffraction grating surface 42 by the convex lens 44 and is emitted by the reflecting mirror 47 in the direction of the converging lens that focuses the laser on the target surface as a laser beam having the original optical axis. Is done.
[0034]
Since the light path length is different between the light beam reflected by the projected surface and the light beam reflected by the receded surface, the laser beam emitted from the reflecting mirror 47 and applied to the target has a time waveform having two peaks. become.
Since the influence on the X-ray intensity is observed from a time interval of several fs, the use of a deformable mirror provides a sufficient effect.
Since the surface shape of the deformable mirror can be arbitrarily selected, the intensity of each peak and the time interval between peaks can be adjusted or a plurality of peaks can be provided in the time waveform of the laser beam.
[0035]
【The invention's effect】
If the X-ray generator or X-ray generation method of the present invention is used, the intensity of X-rays can be adjusted when plasma is emitted by a laser to emit X-rays. Can be selectively adjusted.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an X-ray generator in an embodiment of the present invention.
FIG. 2 is a conceptual diagram showing an example of a spatial phase distribution adjusting mechanism used in the present embodiment.
FIG. 3 is a diagram showing an example of a time waveform of a laser beam at a condensing position in the apparatus of the present embodiment.
FIG. 4 is a flowchart showing a control flow in the apparatus of the present embodiment.
FIG. 5 is a conceptual diagram showing another example of a spatial phase distribution adjusting mechanism used in the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ultrashort light pulse laser generator 2, 5, 11 Laser beam 3 Spatial phase distribution adjustment mechanism 4 Reflective mirror 6 Convex lens or concave mirror 7 Target 8 X-ray 9 Vacuum container 10 X-ray spectrometer 12 Waveform measuring instrument 13 Data processing apparatus 14 Control devices 31, 32 Diffraction gratings 33, 34 Convex lenses or concave mirrors 35 Transmission optical elements 36, 37 which are spatial frequency filters Reflective mirrors 41, 42 Diffraction gratings 43, 44 Convex lenses or concave mirrors 45 Deformable mirrors 46, 47 Reflection mirrors

Claims (17)

In an X-ray generator that generates X-rays by condensing and irradiating a laser beam on a target, the spectrum spreads in a direction perpendicular to the optical axis in the laser beam transmission path and is effective for each portion of the light beam forming a Fourier plane. The spatial phase distribution is adjusted by changing the appropriate optical path length, the pulse time waveform of the laser beam at the position focused on the target is shaped into a predetermined pattern, and the adjusted laser beam is converged and collected on the target. A method of illuminating, characterized by measuring the intensity characteristics of the generated X-ray and adjusting the pulse time waveform of the laser beam so that the X-ray intensity is appropriate based on the measurement result X-ray generation method. 2. The X-ray generation method according to claim 1, further comprising: monitoring a wavefront state of the laser beam after the spatial phase adjustment to confirm a time waveform adjustment state of the laser beam. The X-ray generation method according to claim 1, wherein the light beam forming the Fourier plane is formed by a spectrum resolving optical element. 4. The intensity characteristic of the X-ray to be measured includes a wavelength characteristic, and the pulse time waveform is adjusted based on a measured value of the X-ray intensity at a specific wavelength. The X-ray generation method as described. 5. The X-ray generation method according to claim 1, wherein an ultrashort optical pulse laser is used for the laser light. 6. The X-ray generation method according to claim 1, wherein a pulse time waveform pattern of a laser beam at a position focused on the target has a plurality of peaks. 7. The X-ray generation according to claim 6, wherein the pulse time waveform has two peaks, and the spatial phase distribution of the laser beam is adjusted using the intensity ratio and time interval of the preceding pulse and the subsequent pulse as parameters. Method. In an X-ray generator for irradiating a target with a laser beam to generate X-rays, a mechanism for decomposing the spectrum of the laser beam in a direction perpendicular to the optical axis in the laser beam transmission optical system and a mechanism for adjusting the spatial phase distribution of the laser beam And a laser beam converging mechanism, and an X-ray measuring device for measuring the intensity of generated X-rays is disposed on the target unit, the X-ray intensity is measured by the X-ray measuring device, and the X-ray intensity is measured based on the measurement result. The effective optical path length is adjusted for each portion of the light flux by the spatial phase distribution adjusting mechanism, and the pulse time waveform of the laser beam at the position focused on the target becomes a predetermined pattern having a plurality of peaks, and X An X-ray generator characterized by adjusting the line intensity to be appropriate. Furthermore, a measuring device for measuring the pulse waveform of the laser beam is disposed at a position that has passed through the spatial phase distribution adjustment mechanism, and the adjustment state of the spatial phase distribution adjustment mechanism is appropriately monitored by monitoring the pulse time waveform of the laser beam. The X-ray generator according to claim 8, characterized in that: Mechanism decompose the spectrum of the laser beam, X-rays according to claim 8, wherein deploying the spectral separation optical element in the laser beam delivery optics to space by decomposing the spectrum of the laser beam Generator. The X-ray generation apparatus according to claim 10, wherein the spectral resolution optical element is a diffraction grating or a prism. The X-ray generator according to claim 10 or 11, wherein the mechanism for expanding the spectrum of the laser beam comprises a pulse stretcher or a pulse compressor used for a chirp amplification mechanism of an ultrashort optical pulse laser. X-ray generator according to any one of 12 claims 8, wherein the laser light is ultrashort pulsed laser. The X-ray measuring apparatus, as it can measure the wavelength characteristics to claim 8 13, characterized by adjusting the spatial phase distribution adjustment mechanism based on the laser intensity at a particular wavelength The X-ray generator described. 9. The spatial phase distribution adjusting mechanism includes a deformable mirror, and locally adjusts unevenness of a reflecting surface for each laser beam incident position to control an effective optical path length of the laser beam. The X-ray generator in any one of 14 thru | or 14 . The spatial phase distribution adjustment mechanism, either one of claims 8, characterized in that controlling the effective optical path length of the laser beam by using a transmission type optical element which can be adjusted locally the refractive index 14 of the X-ray generator described in 1. Having the pulse time waveform of two peaks, one adjusting the spatial phase distribution of the laser beam preceding pulse and the intensity ratio and time interval of the subsequent pulse as a parameter from claim 8, wherein the 16 X-ray generator described in 1.

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