High-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration

Abstract

This application belongs to the field of particle acceleration technology and relates to a high-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration. The system includes: a laser source, a vacuum target chamber, a transmission and focusing device, a solid target, and a beam separation module. The laser source is located outside the vacuum target chamber and serves as the input terminal. The beam separation module is located outside the vacuum target chamber and serves as the output terminal. The transmission and focusing device and the solid target are both located inside the vacuum target chamber. The surface of the solid target has multiple arrayed rotating body structures, the generatrix of which is a sine curve, and the centerline of the rotating body structure faces the laser source. The laser source generates laser light, which, after passing through the transmission and focusing device, is injected into the solid target. After being modulated by the solid target, an electron beam is emitted. The electron beam, under the action of the beam separation module, generates a high-energy, high-yield electron beam. This application enables the generation of high-energy, high-yield electron beams.

Description

Technical Field

[0001] This application relates to the field of particle acceleration technology, and in particular to a high-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration. Background Technology

[0002] The interaction between lasers and matter is one of the core problems that has always been of great interest in physics. With the development of ultra-intense laser technology, it is now possible to obtain lasers with intensity 10⁻⁶ lasers in laboratories. 21 -10 23 W / cm 2 With its high laser intensity, matter can be directly ionized into plasma. Novel particle accelerators based on ultra-intense laser-plasma interaction exhibit acceleration gradients more than three orders of magnitude higher than traditional particle accelerators, and generate electron pulses with ultra-short, ultra-bright, and collimated characteristics, thus attracting widespread attention from researchers both domestically and internationally in recent years. High-energy, high-yield electron beams obtained through laser-plasma interaction have significant value in secondary particle generation, free-electron lasers, and ion acceleration. In particular, the quality of the ion beam obtained through electron beam generation for ion acceleration is closely related to the electron beam; increasing the energy and yield of ultrathermal electrons can significantly improve important qualities such as ion beam energy and optimize ion beam collimation. High-energy, high-yield electron beams have broad application prospects in numerous fields.

[0003] In recent years, various electron acceleration mechanisms have been proposed, among which laser relativistic transparency acceleration based on the interaction between a laser and a 100-nanometer solid thin target has been proven by numerous theoretical and experimental studies to be a relatively effective acceleration method. However, the energy conversion efficiency from laser to electron during the laser-to-plate target interaction process is relatively low, resulting in low energy and yield of the obtained electron beam. The low energy and yield of the electron beam limit its application value in many fields. Summary of the Invention

[0004] Therefore, it is necessary to provide a high-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration to address the aforementioned technical problems, which can generate high-energy, high-yield electron beams.

[0005] A high-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration includes:

[0006] Laser source, vacuum target chamber, transmission and focusing device, solid target, and beam separation module;

[0007] The laser source is located outside the vacuum target chamber and serves as the input end; the beam separation module is located outside the vacuum target chamber and serves as the output end; the transmission focusing device and the solid target are both located inside the vacuum target chamber.

[0008] The surface of the solid target is provided with multiple arrayed rotating structures, the generatrix of the rotating structures is a sine curve, and the center line of the rotating structures faces the laser source.

[0009] The laser source generates laser light, which is then transmitted and focused by the transmission and focusing device and then directed into the solid target. After being modulated by the solid target, an electron beam is emitted. The electron beam is then converted into a high-energy, high-yield electron beam by the beam separation module.

[0010] In one embodiment, the transmission focusing device includes: an optical transmission module and a laser focusing module;

[0011] The optical transmission module is located in the optical path of the laser and changes the direction of the laser before it enters the laser focusing module;

[0012] The laser focusing module receives the emitted laser from the optical transmission module, focuses it, and then directs it into the solid target.

[0013] In one embodiment, the vacuum target chamber has an input window and an output window, wherein the laser enters the vacuum target chamber through the input window and exits the vacuum target chamber through the output window;

[0014] The beam separation module consists of two deflecting magnets, which are respectively located on both sides of the output window and are parallel to the emission direction of the electron beam.

[0015] In one embodiment, the centerline of the rotating body structure is perpendicular to the surface of the solid target, and the centerline of the rotating body structure is parallel to the emitted laser of the laser focusing module.

[0016] In one embodiment, the sine curve has a wavelength of 500 nm and an amplitude of 150 nm.

[0017] In one embodiment, the density of the solid target is 80n. c , where n c This is the critical density of the plasma.

[0018] In one embodiment, the solid target is rectangular, and the rotating structure covers the surface of the solid target.

[0019] In one embodiment, the solid target is a pure hydrogen target.

[0020] In one embodiment, the laser source generates a circularly polarized femtosecond Gaussian laser.

[0021] In one embodiment, the intensity of the femtosecond Gaussian laser is 10. 21 ~10 22 W / cm 2 .

[0022] The aforementioned high-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration employs a surface-modulated high-density solid target. Specifically, a modulation structure is set on the surface of the solid target to modulate it. Through the interaction between a circularly polarized Gaussian laser and the modulated solid target, a high-energy electron beam spectrum with high energy conversion efficiency and cutoff energy and beam yield significantly higher than that of a planar solid target can be generated under current laser technology conditions. The high-yield electron beam can generate a stronger sheath electric field in the vacuum region behind the target, thereby effectively driving ion acceleration. Moreover, sufficiently high-energy electron beams also have important applications in the research of secondary particle generation such as X / γ rays and positrons. Furthermore, by changing the laser intensity, the length and density of the solid target, or the wavelength, density, and amplitude of the modulation structure, the energy spectrum of the generated accelerated electron beam can be effectively adjusted. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a high-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration in one embodiment.

[0024] Figure 2 This is the electron energy spectrum obtained by a high-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration in one embodiment.

[0025] Figure label:

[0026] Laser source 1, optical transmission module 2, laser focusing module 3, solid target 4, beam separation module 5, vacuum target chamber 6. Detailed Implementation

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] This application provides a high-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration, such as... Figure 1 As shown, in one embodiment, it includes: a laser source, a vacuum target chamber, a transmission focusing device, a solid target, and a beam separation module.

[0033] The connection relationship between the components is as follows: the laser source is located outside the vacuum target chamber and serves as the input end; the beam separation module is located outside the vacuum target chamber and serves as the output end; and the transmission focusing device and the solid target are all located inside the vacuum target chamber.

[0034] A laser source generates laser light. Preferably, the laser source generates a circularly polarized femtosecond Gaussian laser with a laser intensity of 10. 21 ~10 22 W / cm 2 .

[0035] The vacuum target chamber 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 laser beam exiting the vacuum target chamber through the output window is an ion beam.

[0036] The transmission and focusing device is used to transmit and focus a laser beam onto a solid target. Preferably, the transmission and focusing device includes an optical transmission module and a laser focusing module; the optical transmission module is located in the optical path of the laser beam and changes the direction of the laser beam before it enters the laser focusing module to protect the equipment; the laser focusing module receives the laser beam emitted from the optical transmission module, focuses it, and then projects it onto the solid target.

[0037] The solid target is a modulation solid target, with multiple arrayed rotating body structures on its surface, i.e., a horizontally and vertically stacked sinusoidal lattice structure. The generatrix of the rotating body structure is a sine curve, and the centerline of the rotating body structure faces the laser source. The rotating body structure serves as the modulation structure of the solid target. Preferably, the centerline of the rotating body structure is perpendicular to the surface of the solid target and parallel to the laser emitted from the laser focusing module. More preferably, the solid target is rectangular, and the rotating body structures cover the entire surface of the solid target, that is, the rotating body structures are distributed in a rectangular array. The solid target can be made of a material containing protons, such as a pure hydrogen target, a plastic target, or a polymer target. Even more preferably, the electron density in the solid target is 80n. c , where n c The plasma critical density is given; the wavelength of the sine curve is 500 nm, and the amplitude is 150 nm. The modulated sine structure significantly improves electron beam energy and yield at scales above 100 nm. Good optimization results can be obtained with the above parameter values. However, when the modulation amplitude is further increased beyond 200 nm, the improvement in electron beam energy and yield becomes less significant. Parameter values ​​can be appropriately selected within this amplitude range according to application requirements. This embodiment does not limit the specific size of the solid target, as long as the laser can completely hit the solid target. Preferably, the solid target thickness is 350 nm to match the 500 nm wavelength sine curve.

[0038] The beam separation module separates the emitted electron beam from the vacuum target chamber to generate an ion beam. Preferably, the beam separation module consists of two deflecting magnets, respectively located on both sides of the output window and parallel to the emission direction of the electron beam, to generate a deflecting magnetic field that deflects the emitted electron beam and generates an ion beam.

[0039] The working process of this application is as follows: A laser source generates a circularly polarized femtosecond Gaussian laser. The femtosecond Gaussian laser is injected into the vacuum target chamber through the input window. After being reversed by the optical transmission module, it is transmitted to the laser focusing module. In the laser focusing module, the laser focal spot is reduced and the energy density is further increased. The focused laser is injected along the axis of the modulated solid target and passes through the modulated solid target. The focused laser interacts with the modulated solid target to generate a high-energy, high-yield electron beam. The accelerated electrons in the electron beam reach the deflection magnetic field through the output window. Under the shaping and deflection effect of the magnetic field, the ions mixed in the electron beam generated by the modulated solid target are deflected, thereby realizing the separation of electrons and ions and generating a high-energy, high-yield electron beam with significantly improved energy and yield.

[0040] The working principle of this application is as follows: When an ultrashort, ultra-intense laser pulse acts on a modulated solid target, the solid target is instantaneously ionized into a plasma state. Under the influence of resonant absorption and vacuum heating effects, the energy of the laser pulse is absorbed by the plasma and heated to generate hyperthermal electrons, which propagate forward continuously within the modulated solid target and eventually enter the vacuum region behind the modulated solid target. This system, by modulating the solid target, can interact with the laser pulse under existing laser conditions to generate a high-energy electron beam with higher cutoff energy and higher hyperthermal electron yield. The micro-modulation structure (i.e., the rotating body structure) on the front surface of the solid target (with the side closest to the laser source as the front surface) improves the energy conversion efficiency from laser to heated electrons, thereby generating a hyperthermal electron beam with higher temperature and higher yield. The energy is about 70% higher than that of an electron beam generated by a solid target with the same laser pulse incident on a plane, and the yield is almost an order of magnitude higher.

[0041] The aforementioned high-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration employs a surface-modulated high-density solid target. Specifically, a modulation structure is set on the surface of the solid target to modulate it. Through the interaction between a circularly polarized Gaussian laser and the modulated solid target, a high-energy electron beam spectrum with high energy conversion efficiency and significantly higher cutoff energy and beam yield than that of a planar solid target can be generated under current laser technology conditions. The high-yield electron beam can generate a stronger sheath electric field in the vacuum region behind the target, effectively driving ion acceleration. Moreover, sufficiently high-energy electron beams also have important applications in the research of secondary particle generation such as X / γ rays and positrons. Furthermore, increasing the laser intensity and the amplitude of the rotating body structure will further increase the cutoff energy and yield of the electron beam. A wavelength of 500 nm for the rotating body structure provides good matching with the laser wavelength; decreasing the wavelength will reduce the electron beam energy and yield.

[0042] In one specific embodiment, a laser-accelerated high-energy, high-yield electron beam generation system includes: a laser source, a vacuum target chamber, an optical transmission module, a laser focusing module, a modulated solid target, and a deflecting magnet.

[0043] The laser source generates a circularly polarized Gaussian laser beam with a laser intensity of 10. 21 ~10 22 W / cm 2 The laser wavelength is λ = 1 μm, the focal spot radius is 4 μm, and the time configuration is trapezoidal, including the rising and falling edges of 1T0 and a plateau distribution region of 10T0. T0 = c / λ, where T0 is the laser period and c is the speed of light in vacuum. The modulation solid target is composed of protons (H+) and electrons (e-), maintaining overall electrical neutrality. The thickness of the modulation solid target is 350 nm, the wavelength of the sinusoidal modulation structure is 500 nm, the amplitude is 150 nm, and the electron density in the modulation solid target is 80 n. c n c This is the critical density of the plasma.

[0044] The laser source generates a beam with an intensity of 10 21 W / cm 2 A circularly polarized Gaussian laser, through an optical transmission module and a laser focusing module within a vacuum target chamber, is focused onto the surface of a solid target along its axis, ionizing the target into a plasma state. Under the influence of resonant absorption and vacuum heating effects, the laser pulse's energy is absorbed by the plasma and heated to generate superthermal electrons. These electrons propagate forward within the solid target, eventually entering the vacuum region behind it. The shaping and deflection effects of a magnetic field deflect the ions trapped within the electron beam generated by the solid target, separating the electrons and ions and producing an electron beam with significantly higher energy and yield than that of an unmodulated planar solid target.

[0045] like Figure 2 As shown, the solid line represents the electron energy spectrum obtained after the laser pulse interacts with the sinusoidal lattice modulated target, while the dashed line represents the electron energy spectrum obtained after the laser pulse interacts with the planar target. The comparison results in the figure show that the sinusoidal modulated target significantly improves the cutoff energy and electron beam yield of the ultrathermal electron beam. Compared to the planar target, the sinusoidal modulated target increases the ultrathermal electron beam cutoff energy by approximately 70% and the electron beam yield by about an order of magnitude.

[0046] 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.

[0047] 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 patent 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 all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A high-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration, characterized in that, include: Laser source, vacuum target chamber, transmission and focusing device, solid target, and beam separation module; The laser source is located outside the vacuum target chamber and serves as the input end; the beam separation module is located outside the vacuum target chamber and serves as the output end; the transmission focusing device and the solid target are both located inside the vacuum target chamber. The surface of the solid target is provided with multiple arrayed rotating structures, namely, a sinusoidal lattice structure with horizontal and vertical superposition. The generatrix of the rotating structure is a sine curve, and the center line of the rotating structure faces the laser source. The laser source generates laser light, which is then transmitted and focused by the transmission and focusing device and then directed into the solid target. After being modulated by the solid target, an electron beam is emitted. The electron beam is then converted into a high-energy, high-yield electron beam by the beam separation module. The centerline of the rotating body structure is perpendicular to the surface of the solid target, and the centerline of the rotating body structure is parallel to the laser. The density of the solid target is 80. n c ,in, n c This is the critical density of the plasma.

2. The high-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration according to claim 1, characterized in that, The transmission focusing device includes: an optical transmission module and a laser focusing module; The optical transmission module is located in the optical path of the laser and changes the direction of the laser before it enters the laser focusing module; The laser focusing module receives the emitted laser from the optical transmission module, focuses it, and then directs it into the solid target.

3. The high-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration according to claim 2, characterized in that, The vacuum target chamber 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. The beam separation module consists of two deflecting magnets, which are respectively located on both sides of the output window and are parallel to the emission direction of the electron beam.

4. The high-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration according to any one of claims 1 to 3, characterized in that, The sine curve has a wavelength of 500 nm and an amplitude of 150 nm.

5. The high-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration according to any one of claims 1 to 3, characterized in that, The solid target is rectangular, and the rotating structure covers the surface of the solid target.

6. The high-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration according to any one of claims 1 to 3, characterized in that, The solid target is a pure hydrogen target.

7. The high-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration according to any one of claims 1 to 3, characterized in that, The laser source generates a circularly polarized femtosecond Gaussian laser.

8. The high-energy, high-yield electron beam generation system based on laser relativistic transparent acceleration according to claim 7, characterized in that, The intensity of the femtosecond Gaussian laser is 10. 21 ~10 22 W / cm 2 .

Images