Ion beam generation system based on interaction of laser and disc target

Abstract

The utility model belongs to the technical field of high-energy particle acceleration, and relates to an ion beam generation system based on interaction of laser and a disc target, which comprises a laser source, a modulation target and a vacuum target chamber, the modulation target is a disc-shaped solid target and is arranged in the vacuum target chamber; the laser source is arranged outside the vacuum target chamber and serves as an input end, and laser generated by the laser source is emitted into the modulation target, interacts with the modulation target and then is emitted out to generate an ion beam; the laser source is used for generating circularly polarized femtosecond Laguerre-Gaussian laser; the femtosecond Laguerre-Gaussian laser has hollow transverse field distribution and longitudinal field distribution with the field intensity larger than 1022 W / cm < 2 >. According to the invention, the energy conversion efficiency from laser to ions can be improved, the collimation and the monoenergy of the ion beam are improved, and the maximum cut-off energy and the peak energy of the ions are improved.

Description

Technical Field

[0001] This application relates to the field of high-energy particle acceleration technology, and in particular to an ion beam generation system based on the interaction between a laser and a disk target. Background Technology

[0002] The interaction between lasers and matter is one of the core issues that has always been of great interest in physics. With the development of laser technology, laboratories can now generate lasers with a laser intensity of 10⁻⁶ ppm. 21 -10 23 W / cm 2 The high intensity of lasers can directly ionize matter into plasma. Novel particle accelerators based on ultra-intense laser-plasma interactions exhibit acceleration gradients more than three orders of magnitude higher than traditional particle accelerators. Furthermore, the generated electron pulses possess characteristics such as ultra-short duration, ultra-brightness, collimation, and high conversion efficiency. These technologies hold significant implications for applications such as ion-driven inertial confinement fusion, beam-target neutron sources, heating of dense matter, tumor therapy, particle beam devices, and satellite anti-missile systems, thus attracting widespread attention from researchers both domestically and internationally in recent years. Among these applications, high-energy, high-conversion-efficiency ion beams obtained through laser-plasma interactions hold crucial value in secondary particle generation, free-electron lasers, and ion acceleration.

[0003] In existing technologies, various ion acceleration mechanisms have been proposed, including: Target Normal Sheath Acceleration (TNSA), Radiation Pressure Acceleration (RPA), Breakout Afterburner Acceleration (BOA), Electrostatic Shock Acceleration, and Dual-Peak Electric Field Acceleration. Among these, the RPA mechanism, with its advantages of good monoenergeticity and collimation of the generated ions, possesses very attractive potential.

[0004] However, the final energy conversion efficiency of laser to high-energy ions via the RPA acceleration mechanism is only 5%-10%. Moreover, due to problems such as transverse instability in the RPA mechanism, the highest proton energy reported experimentally via the RPA mechanism is only 100 MeV, which limits its application in certain fields. Utility Model Content

[0005] Therefore, it is necessary to provide an ion beam generation system based on the interaction between a laser and a disk target to address the above-mentioned technical problems. This system can improve the energy conversion efficiency from laser to ion, enhance the collimation and monoenergeticity of the ion beam, and increase the maximum cutoff energy and peak energy of the ion beam, thereby generating a high-energy, high-quality ion beam.

[0006] An ion beam generation system based on the interaction between a laser and a disk target includes:

[0007] Laser source, modulation target, and vacuum target chamber;

[0008] The modulation target is a disk-shaped solid target and is located in the vacuum target chamber;

[0009] The laser source is located outside the vacuum target chamber and serves as the input terminal. The laser generated by the laser source enters the modulation target and interacts with the modulation target before exiting to generate an ion beam.

[0010] In one embodiment, the laser source generates a circularly polarized femtosecond Laguerre-Gaussian laser.

[0011] In one embodiment, the femtosecond Laguerre-Gaussian laser has a hollow transverse field distribution and a field strength greater than 10. 22 W / cm 2 The longitudinal field distribution.

[0012] In one embodiment, the intensity of the femtosecond Laguerre-Gaussian laser is 10. 22 ~10 23 W / cm 2 .

[0013] In one embodiment, the radius of the modulation target is two-thirds of the focal spot radius of the femtosecond Laguerre-Gaussian laser.

[0014] In one embodiment, the modulation target is a plasma target.

[0015] In one embodiment, the modulation target is a hydrocarbon plasma target.

[0016] In one embodiment, the molar ratio of hexavalent carbon ions, monovalent hydrogen ions, and electrons in the modulation target is 4:1:25.

[0017] In one embodiment, the modulation target is a cylindrical structure, and the ratio of the radius to the height of the cylindrical structure satisfies [8, 9].

[0018] In one embodiment, the distance between the laser source and the modulation target satisfies: ,in, The distance between the laser source and the modulation target. is the laser wavelength.

[0019] The aforementioned ion beam generation system based on the interaction between a laser and a disk target, when the laser acts on the target, electrons are ejected as a whole, forming an electrostatic separation field that pulls the ions forward for acceleration. The powerful force of the ultra-intense LG laser is radially inward, suppressing the lateral motion of the plasma. Furthermore, the radius of the disk target is designed to ensure a more concentrated field intensity distribution of the LG laser during its interaction with the modulated target, resulting in more unified acceleration and thus better stable acceleration. This design scheme can increase the plasma velocity, thereby increasing ion energy, while making ion acceleration more synchronous and stable, improving the monoenergeticity and collimation of the ion beam, and enhancing energy conversion efficiency. Moreover, sufficiently high-energy ion beams have significant application value in driving inertial confinement fusion, beam-target neutron sources, and the heating of warm, dense matter. In addition, by changing the laser intensity and altering the structure and density of the plasma or solid target, the energy spectrum of the generated ion beam can be effectively adjusted; increasing the laser intensity can further increase the cutoff energy of the ion beam. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an ion beam generation system based on the interaction between a laser and a disk target in one embodiment;

[0021] Figure 2 This is a comparison diagram of an ion beam generation system based on the interaction between a laser and a disk target under different carbon-hydrogen ratios in one embodiment.

[0022] Figure 3 This is a proton energy spectrum obtained by an ion beam generation system based on the interaction between a laser and a disk target in one embodiment.

[0023] Figure 4 This is a proton angular distribution diagram obtained by an ion beam generation system based on the interaction between a laser and a disk target in one embodiment.

[0024] Figure label:

[0025] Laser source 1, femtosecond Laguerre-Gaussian laser 2, modulation target 3, ion beam 4, vacuum target chamber 5. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0027] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0028] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. In the description of this application, "multiple sets" means at least two sets, such as two sets, three sets, etc., unless otherwise explicitly specified.

[0029] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0030] Furthermore, the technical solutions of the various embodiments of this application can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this application.

[0031] This application provides an ion beam generation system based on the interaction between a laser and a disk target, such as... Figure 1 As shown, in one embodiment, it includes: a laser source, a modulation target, and a vacuum target chamber.

[0032] The laser source is located outside the vacuum target chamber and serves as the input.

[0033] Preferably, the laser source generates a circularly polarized femtosecond Laguerre-Gaussian laser (LG laser), which has a hollow transverse field distribution and a field strength greater than 10. 22 W / cm 2 The longitudinal field distribution of the femtosecond Laguerre-Gaussian laser has an intensity of 10. 22 ~10 23 W / cm 2 It has an inward mass-force that suppresses the lateral motion of the plasma, thus improving collimation.

[0034] The modulation target is a disk-shaped solid target, which is placed in a vacuum target chamber and has a front surface with the plane on the disk facing the input end. The central axis of the modulation target is set in the optical path of the laser so that the laser is perpendicularly injected into the target center on the front surface of the modulation target.

[0035] Preferably, the radius of the modulation target is two-thirds of the focal spot radius of the femtosecond Laguerre-Gaussian laser, which makes the LG laser have a more concentrated field intensity distribution during the interaction. At the same time, it makes the acceleration more overall, thereby achieving better stable acceleration, resulting in a higher speed and greater energy of the accelerated plasma. In addition, it makes the ion acceleration more synchronized, improving the monoenergeticity and collimation of the ion beam after the interaction.

[0036] More preferably, the modulation target is a hydrocarbon plasma target, and the molar ratio of hexavalent carbon ions, monovalent hydrogen ions, and electrons is 4:1:25, in order to simultaneously optimize the cutoff energy, collimation, and monoenergeticity, increase the cutoff energy, and reduce monoenergeticity (energy dissipation), such as... Figure 2 As shown.

[0037] More preferably, the modulation target is a cylindrical structure with a radius-to-height ratio satisfying [8, 9] to ensure uniform force distribution in all directions, resulting in better stability and collimation, while simultaneously optimizing monoenergeticity, cutoff energy, and peak energy. For example, the radius-to-height ratio of the cylindrical structure is 2:0.245 to further optimize monoenergeticity, cutoff energy, and peak energy simultaneously.

[0038] More preferably, the distance between the laser source and the modulation target satisfies: ,in, The distance between the laser source and the modulation target. The wavelength is set to ensure that the laser beam is focused precisely when it reaches the modulation target, resulting in the smallest possible spot radius and the most concentrated energy.

[0039] The vacuum target chamber provides space for the interaction between the laser and the modulation target, and has an input window and an output window; the laser enters the vacuum target chamber through the input window and exits the vacuum target chamber through the output window; it should be noted that the ion beam that finally exits the vacuum target chamber through the output window is the ion beam.

[0040] In this embodiment, the laser source generates a circularly polarized femtosecond Laguerre-Gaussian laser (LG laser), which is injected into the modulation target through the input window of the vacuum target chamber and interacts with the modulation target to generate an ion beam, which is finally emitted through the output window of the vacuum target chamber.

[0041] The working principle of this application is as follows: a circularly polarized femtosecond Laguerre-Gaussian laser (LG laser) is injected into a modulation target, generating radiation pressure acceleration. The Acceleration-Reduction (RPA) mechanism utilizes the mass dynamics of a high-intensity laser pulse to propel electrons in the modulated target forward (towards the output window), thereby generating a stronger electrostatic separation field to accelerate ions (including protons and carbon ions) within the target. Simultaneously, when a femtosecond Laguerre-Gaussian laser pulse acts on a hydrocarbon plasma target, the significant mass difference between electrons and ions causes the electrons to be rapidly pushed away from the target by radiation pressure, forming an electron layer behind the target and generating an electrostatic field to accelerate the ions. Furthermore, the radiation pressure of the ultra-intense laser acts on the modulated target, accelerating it. During this process, the Laguerre-Gaussian laser exhibits a ring-shaped intensity distribution and circular polarization characteristics, producing a more uniform electrostatic field and angular mass dynamics compared to ordinary Gaussian lasers. This reduces electric field fluctuations on the target surface, suppresses lateral instability, maintains the target structure's integrity, prolongs the duration of radiation pressure acceleration, improves stability, and enhances the collimation and monoenergeticity of the generated ion beam, resulting in a higher-energy, higher-quality ion beam.

[0042] The aforementioned ion beam generation system based on the interaction between a laser and a disk target, when the laser acts on the target, electrons are ejected as a whole, forming an electrostatic separation field that pulls the ions forward for acceleration. Specifically, the powerful force of the ultra-intense LG laser is radially inward, suppressing the lateral motion of the plasma. Furthermore, the radius design of the disk target allows for a more concentrated field intensity distribution of the LG laser when interacting with the modulated target, resulting in more unified acceleration and thus better stable acceleration. This design scheme can increase the plasma velocity, thereby increasing ion energy, while making ion acceleration more synchronous and stable, improving the monoenergeticity and collimation of the ion beam, and enhancing energy conversion efficiency. Moreover, sufficiently high-energy ion beams have significant application value in driving inertial confinement fusion, beam-target neutron sources, and the heating of warm, dense matter. In addition, by changing the laser intensity and altering the structure and density of the plasma or solid target, the energy spectrum of the generated ion beam can be effectively adjusted; increasing the laser intensity can further increase the cutoff energy of the ion beam.

[0043] In one specific embodiment, an ion beam generation system based on the interaction between a laser and a disk target includes: a laser source, a modulation target, and a vacuum target chamber.

[0044] The laser source generates a circularly polarized Laguerre-Gaussian laser beam with an intensity of 6.392 × 10⁻⁶. 22 W / cm 2 The laser wavelength is λ =0.8 μmThe radius of the focal spot is 3 μm The time configuration is The start time is 0 and the end time is 15. T 0, , T 0 represents the laser cycle. c Given the speed of light in a vacuum, the normalized amplitude of the laser electric field is: The direction is perpendicular to the surface of the disk target. The hydrocarbon disk target consists of protons ( ), hexavalent ionized carbon ions ( ) and electrons ( It is composed of ) and maintains overall electrical neutrality, with a thickness of 245. nm The hydrogen ion (proton) density is 8. n c The carbon ion density is 32. n c The electron density is 200 n c ,in, n c The critical density of plasma, with a magnitude of .

[0045] The laser source generates a beam with an intensity of 6.392 × 10⁻⁶. 22 W / cm 2 A circularly polarized Laguerre-Gaussian laser enters a vacuum target chamber and strikes a solid disk target perpendicularly along its axis. Under the influence of the laser's electric field, electrons are pushed away, generating a charge separation field that accelerates ions. The energy of the laser pulse is ultimately transferred to the ions through electrons. Under radiation pressure, the plasma disk target is accelerated, producing an ion beam with higher energy conversion efficiency and monoenergeticity than a conventional Gaussian laser.

[0046] like Figure 3 As shown, the solid line represents the proton energy spectrum obtained after the interaction of a Gaussian laser with a disk target, while the dashed line represents the proton energy spectrum obtained after the interaction of a Laguerre-Gaussian laser with a disk target. The comparison results in the figure show that the Laguerre-Gaussian laser significantly improves the monoenergeticity, cutoff energy, and peak energy of the proton beam. Compared to the Gaussian laser, the proton beam produced by the Laguerre-Gaussian laser exhibits an approximately 406.36% improvement in monoenergeticity (calcifiable, representing current technology), an approximately 14.31% improvement in cutoff energy, an approximately 24.35% improvement in peak energy, and an approximately 18.35% improvement in energy conversion efficiency.

[0047] It should be noted that the performance comparison of the prior art using ordinary Gaussian laser, the prior art using Laguerre-Gaussian laser, and the present application (using Laguerre-Gaussian laser) is shown in Table 1.

[0048] Table 1: Performance Comparison of Different Lasers

[0049]

[0050] It can be seen that the monoenergeticity of this application is improved by 406.36% and 727.39% respectively compared with the prior art, the peak energy is improved by 24.35% and 55.14% respectively compared with the prior art, and the cutoff energy is improved by 14.31% and 9.87% respectively compared with the prior art.

[0051] like Figure 4 As shown, the solid line represents the proton angular distribution obtained after the interaction of the Gaussian laser with the disk target, while the dashed line represents the proton angular distribution obtained after the interaction of the Laguerre-Gaussian laser with the disk target. The comparison results in the figure show that the Laguerre-Gaussian laser significantly improves the collimation of the proton beam.

[0052] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0053] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0054] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. An ion beam generation system based on the interaction between a laser and a disk target, characterized in that, include: Laser source, modulation target, and vacuum target chamber; The modulation target is a disk-shaped solid target and is located in the vacuum target chamber; The laser source is located outside the vacuum target chamber and serves as the input terminal. The laser generated by the laser source enters the modulation target and interacts with the modulation target before exiting to generate an ion beam.

2. The ion beam generation system based on the interaction between a laser and a disk target according to claim 1, characterized in that, The laser source generates a circularly polarized femtosecond Laguerre-Gaussian laser.

3. The ion beam generation system based on the interaction between a laser and a disk target according to claim 2, characterized in that, The femtosecond Laguerre-Gaussian laser has a hollow transverse field distribution and a field strength greater than 10. 22 W / cm 2 The longitudinal field distribution.

4. The ion beam generation system based on the interaction between a laser and a disk target according to claim 3, characterized in that, The intensity of the femtosecond Laguerre-Gaussian laser is 10. 22 ~10 23 W / cm 2 .

5. The ion beam generation system based on the interaction between a laser and a disk target according to any one of claims 1 to 4, characterized in that, The radius of the modulation target is two-thirds of the focal spot radius of the femtosecond Laguerre-Gaussian laser.

6. The ion beam generation system based on the interaction between a laser and a disk target according to any one of claims 1 to 4, characterized in that, The modulation target is a plasma target.

7. The ion beam generation system based on the interaction between a laser and a disk target according to claim 6, characterized in that, The modulation target is a hydrocarbon plasma target.

8. The ion beam generation system based on the interaction between a laser and a disk target according to claim 7, characterized in that, The molar ratio of hexavalent carbon ions, monovalent hydrogen ions, and electrons in the modulation target is 4:1:

25.

9. The ion beam generation system based on the interaction between a laser and a disk target according to any one of claims 1 to 4, characterized in that, The modulation target is a cylindrical structure, and the ratio of the radius to the height of the cylindrical structure satisfies [8, 9].

10. The ion beam generation system based on the interaction between a laser and a disk target according to any one of claims 1 to 4, characterized in that, The distance between the laser source and the modulation target satisfies: ,in, The distance between the laser source and the modulation target. is the laser wavelength.

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