Method for realizing spatially uniform isotropic radiation field

Abstract

The application discloses a kind of space uniform distribution's isotropic radiation field implementation method, specific steps are as follows:1. determine the space ball radius of the isotropic radiation field to be realized uniform distribution;2. by uniform distribution random variable, sample spherical polar coordinate parameters, ensure that the direction of incident source obeys space uniform distribution;3. by uniform distribution random variable, sample spherical maximum cross-section circle polar coordinate parameters, ensure that sampling point is uniformly distributed on cross-section circle;4. by the direction of incident source and the direction of cross-section circle, construct coordinate transformation matrix;5. by coordinate transformation matrix and the position distribution of cross-section circle, determine the position distribution of incident source.The method of the application is based on Monte Carlo method, by constructing the direction distribution and position distribution of incident source, to realize the isotropic radiation field of space ball inside uniform distribution.

Description

Technical Field

[0001] This invention belongs to the field of space radiation environment technology, specifically relating to a method for realizing a spatially uniformly distributed isotropic radiation field. Background Technology

[0002] The radiation effects induced by the space radiation environment pose a significant threat to the safe and stable operation of spacecraft. Determining the types, directions, and energies of particles in the radiation environment through radiation detection, and studying the mechanisms of these radiation particles' effects on spacecraft, are key research areas in the field of space radiation environment. Currently, assessing spacecraft radiation effects mainly relies on ground-based acceleration experiments, but the space radiation environment differs significantly from the ground-based radiation environment. The space radiation environment is a spatially uniform, isotropic, mixed radiation field, which is difficult to replicate directly through ground-based experiments. This presents difficulties and challenges for the design of space radiation detectors and the assessment of spacecraft damage caused by space radiation effects.

[0003] To address the above issues, it is necessary to develop a method for realizing a spatially uniformly distributed isotropic radiation field from the perspective of numerical simulation. Summary of the Invention

[0004] To overcome the problems existing in the prior art, the present invention aims to provide a method for realizing a spatially uniform isotropic radiation field. This method innovatively proposes a method for realizing a spatially uniform isotropic radiation field based on the Monte Carlo method.

[0005] It provides support for the design of space radiation detectors and the assessment of space radiation effects on spacecraft.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] A method for realizing a spatially uniform isotropic radiation field is proposed. This method determines the radius of the spatial sphere from which the spatially uniform isotropic radiation field is to be realized. Based on the Monte Carlo method, the polar coordinate parameters of the sphere are sampled using uniformly distributed random variables to ensure that the direction of the incident source follows a spatially uniform distribution. Combined with the direction of the constructed cross-sectional circle, a coordinate transformation matrix is ​​established. This matrix transforms the positional distribution of the cross-sectional circle constructed from the uniformly distributed random variables into the positional distribution of the incident source. Ultimately, the incident source can realize a uniformly distributed isotropic radiation field within the spatial sphere, providing support for space radiation detection and radiation effects analysis.

[0008] Includes the following steps:

[0009] Step 1: Determine the radius R of the spatial sphere from which the isotropic radiation field to be uniformly distributed in space is to be achieved, with the center of the sphere regarded as the origin of the coordinate system;

[0010] Step 2: Sample the spherical polar coordinate parameters using uniformly distributed random variables to ensure that the direction of the incident source follows a spatially uniform distribution. The specific method is as follows:

[0011] θ d =arccos(2ξ-1)

[0012]

[0013]

[0014]

[0015] z d =R×cosθ d

[0016] In the formula, ξ is a random variable with a standard uniform distribution, and R,θ d , Let x be the polar coordinates of the spherical sampling point. d ,y d ,z d Let x be the rectangular coordinates of the spherical sampling point, and let the incident source direction vector be (x). d ,y d ,z d );

[0017] Step 3: Sampling of the polar coordinate parameters of the sphere's maximum cross-section circle using uniformly distributed random variables, ensuring that the sampling points are uniformly distributed on the cross-section circle. The specific method is as follows:

[0018]

[0019]

[0020]

[0021]

[0022]

[0023] z a =0

[0024] In the formula, r a ,θ a , Let x be the polar coordinates of the sampling point on the cross-section circle. a ,y a ,z a Here are the rectangular coordinates of the sampling points on the cross-section circle, with the direction of the cross-section circle being the positive z-axis;

[0025] Step 4: Construct the coordinate transformation matrix Z based on the incident source direction and the direction of the cross-sectional circle. The specific method is as follows:

[0026] (x d ,y d ,z d ) T =Z(0,0,R) T

[0027]

[0028] Step 5: Determine the location distribution of the incident source using the coordinate transformation matrix and the position distribution of the cross-sectional circle. The specific method is as follows:

[0029]

[0030] In the formula, x p ,y p ,z p Let be the rectangular coordinates of the incident source position. After determining the direction and position distribution of the incident source, the incident source can achieve a uniformly distributed isotropic radiation field within the sphere.

[0031] The present invention has the following beneficial effects:

[0032] 1. This invention is based on the Monte Carlo method to achieve a spatially uniform and isotropic radiation field whose accuracy does not change with the radius of the spatial sphere. The radius of the spatial sphere can be adjusted to the radius of the sample's circumscribed sphere according to the shape of the irradiated sample, which effectively improves the simulation efficiency.

[0033] 2. In the sampling of the incident source position distribution, the present invention adopts the circular polar coordinate sampling method, which reduces the number of times trigonometric functions are used and improves the calculation speed compared with spherical polar coordinate sampling;

[0034] 3. This invention provides a method for constructing a spatially uniform and isotropic radiation field using uniform surface sources distributed at different locations, providing theoretical support for space radiation environment detection and radiation effect research, and offering inspiration for achieving a spatially uniform and isotropic radiation field using ground-based radiation sources. Attached Figure Description

[0035] Figure 1 A flowchart illustrating the method for realizing a spatially uniformly distributed isotropic radiation field.

[0036] Figure 2 A schematic diagram showing the distribution of incident source locations with a fixed direction.

[0037] Figure 3 This is a reliability verification diagram showing the uniform spatial distribution of the radiation field.

[0038] Figure 4 The figures show the reliability verification diagrams for the isotropic nature of the radiation field. Figure (a) shows the cosine distribution of the polar coordinate angle θ in the ray direction, and Figure (b) shows the polar coordinate angle in the ray direction. distributed. Detailed Implementation

[0039] The Monte Carlo particle transport simulation software is used to construct the incident source position and orientation distribution to achieve a spatially uniform isotropic radiation field. A spherical detector is then constructed within the radiation field to verify the reliability of the spatially uniform isotropic radiation field. A detailed description is provided below with reference to the accompanying figures. Figure 1 As shown, the present invention provides a method for realizing a spatially uniformly distributed isotropic radiation field, comprising the following steps:

[0040] Step 1: Determine the radius R of the spatial sphere from which the isotropic radiation field to be uniformly distributed in space is to be achieved, with the center of the sphere regarded as the origin of the coordinate system;

[0041] Step 2: Sample the spherical polar coordinate parameters using uniformly distributed random variables to ensure that the direction of the incident source follows a spatially uniform distribution. The specific method is as follows:

[0042] θ d =arccos(2ξ-1)

[0043]

[0044]

[0045]

[0046] z d =R×cosθ d

[0047] In the formula, ζ is a random variable with a standard uniform distribution, and R,θ d , Let x be the polar coordinates of the spherical sampling point. d ,y d ,z d Let x be the rectangular coordinates of the spherical sampling point, and let the incident source direction vector be (x). d ,y d ,z d );

[0048] Step 3: Sampling of the polar coordinate parameters of the sphere's maximum cross-section circle using uniformly distributed random variables, ensuring that the sampling points are uniformly distributed on the cross-section circle. The specific method is as follows:

[0049]

[0050]

[0051]

[0052]

[0053]

[0054] z a =0

[0055] In the formula, r a ,θ a , Let x be the polar coordinates of the sampling point on the cross-section circle. a ,y a ,z a Here are the rectangular coordinates of the sampling points on the cross-section circle, with the direction of the cross-section circle being the positive z-axis.

[0056] Step 4: Construct the coordinate transformation matrix Z based on the incident source direction and the direction of the cross-sectional circle. The specific method is as follows:

[0057] (x d ,y d ,z d ) T =Z(0,0,R) T

[0058]

[0059] Step 5: Determine the location distribution of the incident source using the coordinate transformation matrix and the position distribution of the cross-sectional circle. The specific method is as follows:

[0060]

[0061] In the formula, x p ,y p ,z p Let be the rectangular coordinates of the incident source position. Figure 2 This is a schematic diagram of the distribution of incident sources with a defined direction. After determining the direction and location of the incident sources, the incident sources can achieve a uniformly distributed isotropic radiation field within the sphere.

[0062] Step 6: Construct 4 spherical detectors with radius r and centers located at (0,0,0). At these four locations, the spatial fluence Φ of the particles, the cosine distribution of the polar coordinate angle θ of the ray direction, and the... The distribution is used to test the homogeneity and isotropy of the radiation field within the space sphere.

[0063] To reduce statistical fluctuations in the Monte Carlo method, this case uses an incident particle number of n = 10. 8 R = 1 cm, r = 1 mm, the expected spatial flux is like Figure 3 and Figure 4 As shown, the actual particle flux at the four locations matches the expected flux, and the polar coordinate angle θ cosine distribution of the ray direction at the four locations is consistent with... The fact that the distribution is uniform indicates that the spatially uniform isotropic radiation field achieved by this invention is reliable.

[0064] The above content is a further explanation of the method for realizing a spatially uniformly distributed isotropic radiation field based on a specific scheme. The parts not explained in detail are common knowledge to those skilled in the art.

Claims

1. A method for realizing a spatially uniformly distributed isotropic radiation field, characterized in that: The radius of the spatial sphere from which the isotropic radiation field to be uniformly distributed in space is determined. Based on the Monte Carlo method, the polar coordinate parameters of the sphere are sampled using uniformly distributed random variables to ensure that the direction of the incident source follows a uniform spatial distribution. Combined with the direction of the constructed cross-sectional circle, a coordinate transformation matrix is ​​established. The position distribution of the cross-sectional circle constructed by the uniformly distributed random variables is transformed into the position distribution of the incident source through the coordinate transformation matrix. Finally, the incident source can achieve a uniformly distributed isotropic radiation field within the spatial sphere, providing support for carrying out space radiation detection and radiation effects. The method includes the following steps: Step 1: Determine the radius of the spatial sphere from which the isotropic radiation field with uniform spatial distribution is to be achieved. R The center of the sphere is considered the origin of the coordinate system; Step 2: Sample the spherical polar coordinate parameters using uniformly distributed random variables to ensure that the direction of the incident source follows a spatially uniform distribution. The specific method is as follows: In the formula, Let be a random variable with a first-standard uniform distribution. The polar coordinates of the spherical sampling points. Let be the rectangular coordinates of the spherical sampling point, and let the incident source direction vector be . ; Step 3: Sampling of the polar coordinate parameters of the sphere's maximum cross-section circle using uniformly distributed random variables, ensuring that the sampling points are uniformly distributed on the cross-section circle. The specific method is as follows: In the formula, Let be a random variable with a second standard uniform distribution. The polar coordinates of the sampling points on the cross-section circle are... Here are the rectangular coordinates of the sampling points on the cross-section circle, with the direction of the cross-section circle being the positive z-axis; Step 4: Construct the coordinate transformation matrix Z based on the incident source direction and the direction of the cross-sectional circle. The specific method is as follows: Step 5: Determine the location distribution of the incident source using the coordinate transformation matrix and the position distribution of the cross-sectional circle. The specific method is as follows: In the formula, Let be the rectangular coordinates of the incident source position. After determining the direction and position distribution of the incident source, the incident source can achieve a uniformly distributed isotropic radiation field within the sphere.

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