Method for efficiently generating high-brightness gamma radiation

Abstract

The invention discloses a method for efficiently generating high-brightness gamma radiation, and belongs to the technical field of radiation. A relativistic electron beam is injected into the porous microstructure foam target material, and high-brightness gamma ray radiation is generated. According to the method, the used device is simple, only the single relativistic electron beam and the porous microstructure foam target material are needed to interact, compared with a traditional uniform-density solid material, the energy conversion efficiency in the interaction process of the electron beam and a substance can be remarkably improved, and the energy conversion efficiency can be remarkably improved through the effective constraint effect of a high-intensity magnetic field. And the problems of low energy conversion rate, low light source brightness, poor radiation directivity, complex device or difficulty in experiment implementation and the like of the existing high-energy gamma ray radiation source are solved.

Description

Technical Field

[0001] This invention relates to the field of radiation technology, and more specifically to a method for efficiently generating high-brightness gamma radiation. Background Technology

[0002] High-energy radiation sources have important applications in nuclear physics, materials science, and medical imaging. Currently, commonly used high-energy gamma radiation generation mechanisms mainly include bremsstrahlung, Compton scattering, and synchrotron radiation. Bremsstrahlung generates gamma photons by slowing down high-energy electrons in a high-Z target; although the device is simple, the radiation directionality is poor and the brightness is low. Compton scattering mainly utilizes the collision of a high-energy electron beam with a high-intensity laser to generate quasi-monoenergetic gamma light, which has good directionality, but the energy conversion efficiency is low, and the experimental system is complex, requires high alignment precision, and is expensive. Synchrotron radiation sources rely on the torsional motion of electrons in a magnetic field to radiate high-brightness photons, but require large accelerators and magnetic systems, resulting in extremely high construction and operating costs.

[0003] In summary, existing high-energy gamma-ray radiation sources generally suffer from low energy conversion efficiency, low light source brightness, and complex or difficult-to-implement devices. Therefore, there is an urgent need to invent a new method for generating high-energy gamma rays. Recently, new schemes have been proposed to address these issues, such as the scheme of generating gamma rays through synchrotron radiation via the interaction of a relativistic electron beam with a solid target. This scheme can obtain high-energy gamma photons; however, the unstable transmission of the electron beam within the solid target will degrade the quality of the radiation source, greatly limiting its brightness and conversion efficiency. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a method for efficiently generating high-brightness gamma radiation, thereby solving the problems of low energy conversion efficiency, low light source brightness, complex devices, or difficulties in implementation that are common in existing high-energy gamma-ray radiation sources.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: In a first aspect, the present invention provides a method for efficiently generating high-brightness gamma radiation, comprising the following steps: injecting a relativistic electron beam into a porous microstructured foam target to generate high-brightness gamma radiation.

[0006] The beneficial effects of this invention are as follows: This invention directly applies a relativistic electron beam to a foam target material with a porous microstructure to achieve the generation of high-brightness gamma-ray radiation. When the relativistic electron beam is injected into the porous microstructured foam, the strong electromagnetic field of the electron beam itself instantaneously (attosecond scale) ionizes the foam target material into plasma. Simultaneously, the timescale of plasma diffusion formed on the foam target material (picosecond to nanosecond) is much longer than the pulse length of the electron beam (typically tens of femtoseconds). When the electron beam propagates in this type of plasma, a very strong backflow current is generated on the foam skeleton to maintain current balance. This backflow current further excites a very strong magnetic field. The magnetic field focuses the electron beam and also provides a strong background electromagnetic field environment for photoelectron emission. As the electron beam focuses, its peak density can increase by tens of times, resulting in a corresponding increase in the backflow current, ultimately leading to a further enhancement of the magnetic field in the pores of the foam target material. The relativistic electron beam oscillates laterally in a strong magnetic field environment within a foam target and, due to quantum electrodynamics, efficiently emits high-energy gamma photons, thus achieving the efficient generation of high-brightness gamma-ray radiation.

[0007] Furthermore, when injecting a relativistic electron beam into a porous microstructured foam target, it is not necessary to precisely control the interaction angle between the relativistic electron beam and the target.

[0008] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The device used in the method of generating high-brightness gamma radiation by the present invention is simple. It only needs to generate a relativistic electron beam through a relativistic electron beam generating device to directly act on the porous microstructure foam target material. No additional laser collision system or control of the action angle is required. This realizes the simple and low-cost generation of high-energy gamma rays and solves the problem of complex devices that are common in existing high-energy gamma ray radiation sources.

[0009] Furthermore, relativistic electron beams are generated via laser wake accelerators or linear accelerators.

[0010] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the relativistic electron beam used in this invention can be directly generated by a laser wake accelerator or a traditional linear accelerator, and is easy to obtain.

[0011] Furthermore, the energy of the relativistic electron beam is 1–10 GeV, and the initial peak electron beam density is 1 × 10⁻⁶. 18 -1×10 21 cm -3 .

[0012] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the present invention has lower requirements for the initial energy and peak density of the relativistic electron beam incident on the porous microstructure foam target and a wider range, and has lower requirements for the production equipment of the electron beam, thus solving the problems of complex existing high-energy gamma-ray radiation source devices or difficult experimental implementation.

[0013] Furthermore, the porous microstructured foam includes any one of polystyrene foam, carbon nanotube foam, CHO foam, silica foam, and 3D printed foam.

[0014] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the present invention has low requirements for the material or source of porous microstructure foam. As long as the foam material has the corresponding filling coefficient and pore size, the generation of high-brightness gamma rays can be achieved, thus broadening the selection range of radiation source target materials.

[0015] Furthermore, the filling coefficient of the porous microstructured foam is ≤15%, and the average pore size is 1-12 μm.

[0016] Furthermore, the filling coefficient of the porous microstructure foam is 0.05%-15%.

[0017] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The present invention can adjust the energy conversion efficiency of generating high-brightness gamma rays by adjusting the basic characteristics of porous microstructures such as the filling coefficient and pore size of porous microstructure foam and the basic characteristics of incident relativistic electron beams, thereby meeting the needs of gamma ray sources in different application scenarios and broadening the application scenarios.

[0018] Furthermore, the relativistic electron beam travels a distance of 50 μm-10 mm in the porous microstructured foam target.

[0019] A second aspect of the present invention provides a radiation source for efficiently generating high-brightness gamma radiation, comprising a relativistic electron beam generating unit and a target unit, wherein the relativistic electron beam generating unit generates an electron beam that directly acts on the target unit.

[0020] The beneficial effects of this invention are as follows: This invention provides a radiation source capable of efficiently generating high-brightness gamma radiation. The main structure includes only a relativistic electron beam generating unit and a target unit. The device is simple, does not require a large accelerator and magnetic system, has low construction and operation costs, and is highly adjustable. It can generate gamma radiation with different conversion efficiencies and brightness by replacing the parameters of the relativistic electron beam generating unit and the target unit, and is highly convenient.

[0021] Furthermore, the relativistic electron beam generating unit is a laser wake accelerator or a linear accelerator.

[0022] Furthermore, the target material unit is a porous microstructured foam.

[0023] Furthermore, the porous microstructured foam includes any one of polystyrene foam, carbon nanotube foam, CHO foam, silica foam, and 3D printed foam.

[0024] Furthermore, the filling coefficient of the porous microstructured foam is ≤15%, and the average pore size is 1-12 μm.

[0025] A third aspect of the present invention provides an apparatus for efficiently generating high-brightness gamma radiation, comprising the radiation source described above.

[0026] The beneficial effects of the present invention are as follows: The present invention also provides a device for generating high-brightness gamma radiation based on the above-mentioned radiation source. The device is simple and easy to disassemble. There is no need for complex operations such as high-precision alignment between units. It can achieve efficient generation of high-brightness gamma rays.

[0027] The present invention has the following beneficial effects: 1. High energy conversion efficiency. This invention uses porous microstructured foam as the target material, which significantly improves the energy conversion efficiency during the interaction between the electron beam and matter compared to traditional uniform density solid materials. At a transmission distance of 100 μm, the efficiency of converting the electron beam into gamma rays can reach 25%, which is 400 times higher than the interaction between the electron beam and a uniform density solid target material. Furthermore, the average photon energy can be increased by 14 times, solving the problem of low energy conversion efficiency in existing high-energy gamma-ray radiation sources.

[0028] 2. Excellent light source brightness. Compared with traditional uniform density solid materials, the technical solution of this invention can generate a strong magnetic field by incident a relativistic electron beam onto porous microstructure foam. Through the effective confinement of the strong magnetic field, a gamma-ray source with good directionality and a focal spot size of micrometers can be obtained. Its light source brightness is more than three orders of magnitude higher than existing solutions, solving the problems of low light source brightness and poor radiation directionality of existing high-energy gamma-ray radiation sources.

[0029] 3. Simple device. This invention only requires the interaction between a single relativistic electron beam and a porous microstructured foam target. It does not require the introduction of an additional laser collision system, nor does it require precise control of the interaction angle between the electron beam and the target. This solves the problems of complexity or experimental difficulty in existing high-energy gamma-ray radiation source devices. Attached Figure Description

[0030] Figure 1 This is a schematic diagram illustrating the interaction between the relativistic electron beam and the porous microstructured foam target of this invention. Figure 2 This is a diagram showing the distribution of the magnetic field Bz in the foam structure during the interaction between the relativistic electron beam and the porous microstructured foam target of this invention. Figure 3The figures show the simulation results of radiation energy conversion efficiency for embodiments and comparative examples of the present invention. Detailed Implementation

[0031] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer should be followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0032] This invention provides a method for efficiently generating gamma radiation, specifically including the following steps: injecting a relativistic electron beam into a porous microstructured foam target to generate high-brightness gamma-ray radiation.

[0033] A schematic diagram illustrating the interaction between a relativistic electron beam and a porous microstructured foam target according to an embodiment of the present invention is shown below. Figure 1 As shown, the working principle is as follows: When a relativistic electron beam is injected into a porous microstructured foam, its strong electromagnetic field instantaneously (on the attosecond scale) ionizes the foam target into plasma. Simultaneously, the timescale of plasma diffusion (picoseconds to nanoseconds) is much longer than the pulse length of the electron beam (typically tens of femtoseconds). When the electron beam propagates through this type of plasma, a very strong backflow current (current density reaching 10⁻⁶) is generated on the foam skeleton to maintain current balance. 17 A / m 2 The return current will further generate a very strong magnetic field (10). 4 -10 6 T), the magnetic field Bz distribution diagram in the foam structure is as follows: Figure 2 As shown in the attached figure, the porous microstructured foam target generates an extremely strong magnetic field environment after the relativistic electron beam is incident. The magnetic field focuses the electron beam and also provides a strong background electromagnetic field environment for photoelectron emission. With the focusing of the electron beam, the peak density can increase by tens of times, resulting in a corresponding increase in the return current, ultimately leading to a further enhancement of the magnetic field within the pores of the foam target. In the strong magnetic field environment within the foam target, the relativistic electron beam oscillates laterally and, due to quantum electrodynamic effects, efficiently emits high-energy gamma photons.

[0034] In some implementations, the relativistic electron beam is generated via a laser wake accelerator or a linear accelerator.

[0035] The relativistic electron beam generated by the accelerator can be directly injected into a porous microstructured foam target to interact with it and produce high-brightness gamma-ray radiation without the need for precise control of the interaction angle between the relativistic electron beam and the target.

[0036] In some implementations, the resulting relativistic electron beam has an energy of 1-10 GeV and an initial peak electron beam density of 1×10⁻⁶. 18 -1×10 21 cm -3 .

[0037] In some embodiments, the porous microstructured foam target includes any one of polystyrene foam, carbon nanotube foam, CHO foam, silica foam, and 3D printed foam.

[0038] In some preferred embodiments, the porous microstructured foam target is silica foam.

[0039] In some implementations, the filling factor of the porous microstructured foam is ≤15%, and the average pore size is 1-12 μm.

[0040] In some preferred embodiments, the porous microstructured foam has a filling factor of 3%, 1.2%, 0.5% and 0.24%, and an average pore size of 3 μm, 5 μm, 8 μm and 12 μm.

[0041] By adjusting the pore size of the porous microstructure foam used in the examples, gamma rays with different energy conversion efficiencies and brightness can be obtained.

[0042] In some implementations, the relativistic electron beam travels a distance of 50 μm to 10 mm in the porous microstructured foam target.

[0043] In some preferred embodiments, the relativistic electron beam travels a distance of 100 μm in the porous microstructured foam target.

[0044] Example 1: A method for efficiently generating high-brightness gamma radiation (QED-PIC simulation using EPOCH) includes the following steps: S1. By filling the simulation box with randomly distributed skeleton and pores, a porous silica foam structure of 30×100 μm was obtained. The filling coefficient of the foam structure was 0.5%, and the average pore size was 8 μm. S2, from one side of the simulated porous silica foam (e.g.) Figure 1 (As shown in the schematic diagram) The initial injection energy is 1 GeV, and the initial electron beam peak density is 6 × 10⁻⁶. 20 cm -3 A relativistic electron beam propagates 100 μm through a simulated porous silica foam structure, producing high-brightness gamma radiation.

[0045] Examples 2-4: A method for efficiently generating high-brightness gamma radiation includes the following steps: The method in this embodiment is the same as in embodiment 1, except that the porosity of the S1 foam structure in embodiment 1 is changed to 3 μm, 5 μm and 12 μm in sequence.

[0046] Examples 5-8: A method for efficiently generating high-brightness gamma radiation includes the following steps: The method in this embodiment is the same as in embodiments 1-4, except that the initial electron beam peak density of the relativistic electron beam in S2 in embodiments 1-4 is changed to 1×10. 20 cm -3 .

[0047] Comparative Example 1: A method for generating gamma radiation (using EPOCH QED-PIC simulation) includes the following steps: S1. A simulated uniform solid structure of silica is obtained by filling the simulation box; S2, from one side simulating a uniform solid structure of silicon dioxide (e.g.) Figure 1 (As shown in the schematic diagram) The initial injection energy is 1 GeV, and the initial electron beam peak density is 6 × 10⁻⁶. 20 cm -3 A relativistic electron beam propagates 100 μm through a simulated dense silicon dioxide structure, producing high-brightness gamma radiation.

[0048] Comparative Example 2: A method for generating gamma radiation includes the following steps: The method used in this comparative example is the same as that in Comparative Example 1, except that the initial peak electron beam density of the relativistic electron beam in S2 of Comparative Example 1 is changed to 1×10⁻⁶. 20 cm -3 .

[0049] Experimental example: The radiative energy conversion efficiency of gamma radiation simulated by the methods in Examples 1-8 and Comparative Examples 1-2 was characterized, and the results are as follows: Figure 3 As shown.

[0050] The results show that the radiation energy conversion efficiency of the porous microstructured foam used as the target material for gamma radiation preparation in the embodiments of the present invention is significantly higher than that of the dense non-porous structures in Comparative Example 1 and Comparative Example 2. At the same time, as the pore size of the porous microstructured foam gradually increases in the range of 3-12 μm, the radiation energy conversion efficiency also gradually increases. In addition, as the initial electron beam peak density of the relativistic electron beam increases, the radiation energy conversion efficiency of gamma radiation is also significantly improved.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for efficiently generating high-brightness gamma radiation, characterized in that, Includes the following steps: Injecting a relativistic electron beam into a porous microstructured foam target produces high-brightness gamma-ray radiation.

2. The method for efficiently generating high-brightness gamma radiation according to claim 1, characterized in that, The relativistic electron beam is generated by a laser wake accelerator or a linear accelerator.

3. The method for efficiently generating high-brightness gamma radiation according to claim 1 or 2, characterized in that, The relativistic electron beam has an energy of 1-10 GeV and an initial peak electron beam density of 1×10⁻⁶. 18 -1×10 21 cm -3 .

4. The method for efficiently generating high-brightness gamma radiation according to claim 1, characterized in that, The porous microstructured foam includes any one of polystyrene foam, carbon nanotube foam, CHO foam, silica foam, and 3D printed foam.

5. The method for efficiently generating high-brightness gamma radiation according to claim 1 or 4, characterized in that, The porous microstructured foam has a filling coefficient of ≤15% and an average pore size of 1-12 μm.

6. The method for efficiently generating high-brightness gamma rays according to claim 1, characterized in that, The relativistic electron beam travels a distance of 50 μm-10 mm in the porous microstructured foam target.

7. A radiation source that efficiently generates high-brightness gamma radiation, characterized in that, It includes a relativistic electron beam generating unit and a target unit, wherein the relativistic electron beam generating unit generates an electron beam that directly acts on the target unit.

8. The high-efficiency gamma radiation source according to claim 7, characterized in that, The relativistic electron beam generating unit is a laser wake accelerator or a linear accelerator.

9. The high-efficiency gamma radiation source according to claim 7, characterized in that, The target material unit is a porous microstructured foam; the porous microstructured foam includes any one of polystyrene foam, carbon nanotube foam, CHO foam, silica foam and 3D printing foam; the filling coefficient of the porous microstructured foam is ≤15%, and the average pore size is 1-12 μm.

10. A device for efficiently generating high-brightness gamma radiation, characterized in that, Includes the radiation source as described in any one of claims 7-9.

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