Evaluation method for radiation shielding performance of encapsulation and reinforcement material for deep space exploration and radiation resistance of spaceflight chip

Abstract

The application relates to an evaluation method for radiation shielding performance of a packaging reinforced material and radiation resistance of an aerospace chip for deep space exploration, and belongs to the field of aerospace and radiation protection. 60 The present application is unable to correctly feedback the radiation shielding performance and operation state of the packaging reinforced material and the chip in the actual deep space radiation environment at present. The application adopts an electron-proton combined test method, restores the real deep space radiation environment of the spacecraft in orbit operation as much as possible based on the ground test system condition, and is used for testing and evaluating the radiation resistance of the anti-radiation packaging reinforced material and the radiation resistance of the chip, so as to judge whether the packaging reinforced electronic device meets the anti-radiation requirement under the actual application condition. The application realizes the evaluation of the radiation resistance performance of the packaging reinforced material and the radiation resistance performance of the chip in the deep space exploration radiation environment.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of aerospace and radiation protection, and particularly relates to a method for evaluating the radiation shielding performance of a packaging and reinforcing material and the anti-radiation performance of electronic devices for deep space exploration. BACKGROUND

[0002] In recent years, with the gradual development of the aerospace industry, China's space activities have gradually moved from Earth orbit exploration to deep space exploration. High-energy electron rays and high-energy proton rays are one of the most notable characteristics of deep space charged particle radiation environment, and are the main research object of space environment. The study of the energy spectrum of different types of charged particles from deep space environment helps humans further understand the deep space radiation environment, which provides on-orbit stable service guarantee for improving the design of spacecraft.

[0003] Electronic equipment systems are the core systems of spacecraft such as deep space exploration. Among them, space chips play a key role in device power supply and information storage, and are known as the heart and brain of electronic equipment. The reliability of the space chip directly determines the success or failure of the space mission. During the on-orbit period of the spacecraft, the energy of high-energy electrons and protons and other deep space radiation gradually accumulates on the chip, which will seriously threaten the stability of the chip and even cause complete failure. As humans explore space farther and farther, the on-orbit time of the chip is gradually extended, and the space chip needs to be anti-radiation reinforced to improve the anti-radiation performance.

[0004] Common radiation reinforcement methods include design reinforcement, process reinforcement and packaging reinforcement. Design reinforcement and process reinforcement both need to be specially developed and developed for chips, which has a long design cycle, high tape-out cost and is not universal for all types of chips. The performance improvement has far failed to meet the requirements. The core of packaging reinforcement is to physically isolate the chip from the radiation environment by using radiation shielding materials, which has the characteristics of low cost, short cycle, strong universality and easy operation. It can truly realize high efficiency, convenience, low cost and rapid development, and is recognized as an effective way to improve the reliability, stability and service life of electronic devices. Therefore, packaging reinforcement is considered to be one of the important means for the great-leap-forward improvement of the anti-radiation performance of chips under the rapid development of China's aerospace industry.

[0005] The accurate evaluation of the anti-radiation packaging and reinforcing performance of the chip is a necessary prerequisite for the evaluation of the shielding performance of the material and the working stability of the chip. Domestic work on building devices on ground systems to restore deep space radiation environment as much as possible started late. At present, the anti-radiation performance of the chip mainly uses 60The gamma rays generated by Co are used to evaluate the total dose effect and working stability of the chip. Although the high-penetration gamma rays can quickly and conveniently and at low cost evaluate the damage effect of the chip, the deep space radiation environment is mainly composed of electrons and protons, and the interaction mechanisms of different types of rays and matter are completely different. In addition, there is no method that can guide the test of the anti-radiation performance of the shielding material in the actual deep space radiation environment under the ground system in the field of aviation and aerospace. This situation cannot determine whether the shielding material can further improve the anti-radiation performance of the electronic device in the running orbit of the electronic device, and cannot more directly guide the material selection design of the anti-radiation packaging and reinforcement, which is not conducive to the development of the anti-radiation packaging and reinforcement technology. Therefore, it is urgent to establish an evaluation method for the radiation shielding performance of the packaging and reinforcement material and the anti-radiation performance of the chip based on the real deep space radiation environment, so as to fill the technical gap of the existing evaluation method. SUMMARY

[0006] In order to accurately evaluate the anti-radiation packaging and reinforcement performance of the space chip for deep space exploration, so as to evaluate the shielding performance of the material and the working stability of the chip, the electronic-proton combined test method is adopted, the real deep space radiation environment of the spacecraft in orbit is restored as much as possible under the condition of the ground test system, and the anti-radiation of the anti-radiation packaging and reinforcement material and the anti-radiation performance of the chip are tested and evaluated, so as to determine whether the packaging and reinforcement electronic device meets the anti-radiation requirements under the actual application conditions. With the continuous development of the anti-radiation packaging and reinforcement technology, the evaluation method of the present application shows a broad application prospect.

[0007] In order to achieve the above purpose, the present application provides an evaluation method for the radiation shielding performance of the packaging and reinforcement material for deep space exploration and the anti-radiation performance of the space chip, comprising the following steps:

[0008] S1, orbit environment analysis

[0009] The orbit environment determines the radiation environment of the packaging and reinforcement shielding material of the chip and the chip in orbit. Before the irradiation test starts, the energy composition and the proportion of each part of the radiation particles in the orbit environment are analyzed and determined, and the electron energy spectrum and the proton energy spectrum in the orbit environment are obtained respectively;

[0010] S2, particle energy and flux analysis

[0011] Based on the energy spectrum results output by S1 orbit environment analysis, the type of radiation particles and the accelerator selected are determined, the initial dose of each single energy in the energy spectrum in the single layer silicon detector is calculated by using the simulation software, and the proportion of the irradiation dose of each single energy radiation source in the total dose of the energy spectrum is reasonably distributed;

[0012] S3, dose and fluence conversion of electrons and protons under single energy

[0013] The initial dose of a single energy particle calculated by simulation software is the total irradiation dose at the time of testing at the single energy, and the total irradiation dose is converted into an irradiation total dose;

[0014] S4, material design and optimization

[0015] According to the anti-radiation requirements of the aerospace chip, the element composition and ingredient ratio of the packaging reinforced shielding material are designed, and the thickness of the packaging reinforced shielding material meeting the requirements is calculated by using simulation software;

[0016] S5, electronic irradiation test

[0017] The shielding material to be tested is fixed on the sample table, and the chip to be tested is inserted into the test fixture. According to the electronic total dose analysis and calculation results, the shielding material and the chip are irradiated at the corresponding dose, and the dose meter readings before and after the shielding material are recorded. After the electronic irradiation test is completed, the packaging reinforced shielding material is subjected to low-temperature freezing treatment;

[0018] S6, chip electrical signal test

[0019] The chip after the electronic irradiation test is subjected to electrical signal test and data collection. If the electrical signal is normal, the next test process is carried out. If the electrical signal is not normal, it is determined that the shielding material cannot meet the anti-radiation requirements of the chip;

[0020] S7, proton irradiation test

[0021] The chip with normal electrical signal and the packaging reinforced shielding material are further subjected to proton irradiation test. The shielding material to be tested is fixed on the sample table, and the chip to be tested is inserted into the test fixture. According to the proton total dose analysis and calculation results, the shielding material and the chip are irradiated at the corresponding dose, and the dose meter readings before and after the shielding material are read and recorded.

[0022] S8, analysis and calculation of material shielding performance

[0023] After the proton irradiation test is completed, the shielding material performance test is completed, the dose before and after the shielding material is calibrated by using the dosimeter, the data is analyzed and the shielding performance is calculated. The specific operation is as follows: the dosimeters are placed before and after the shielding material sample, after irradiation, the dosimeters will change color to different degrees according to the size of the irradiation dose. The absorbance of the dosimeter is tested by using the ultraviolet visible spectrophotometer, the test results are compared with the standard control table, the dose value absorbed by the dosimeter before and after irradiation can be obtained, and the radiation shielding rate of the shielding material can be calculated, and the shielding performance of the material is obtained.

[0024] S9, chip electrical signal test

[0025] The chips after electron and proton irradiation test are tested for electrical signal and data are collected. If the electrical signal is normal, the next test procedure is performed; if the electrical signal is not normal, it is determined that the shielding material cannot meet the anti-radiation requirements of the chip.

[0026] S10, chip over-irradiation test and annealing treatment

[0027] The chips with normal electrical signal continue to be subjected to 50% increased dose over-irradiation test, and the chips are tested for electrical signal again after high-temperature annealing. If the test result is qualified, the irradiation test is ended.

[0028] S11, chip anti-radiation performance evaluation

[0029] The running state of the chip is judged by in-situ testing the change of the electrical signal, and the electrical signal of the chip without packaging and reinforcement is compared to judge the anti-radiation performance of the chip in the deep space radiation environment and the packaging and reinforcement effect of the shielding material on the chip.

[0030] Further limitation, the electron and proton energy spectrum in the track environment in step S1 is a differential flux energy spectrum.

[0031] Further limitation, the thickness of the single-layer silicon detector in step S2 is 5um-80um; the types of simulation software include but are not limited to MCNP, Cacino, Fastrad, Omere, etc.; the types of radiation source rays include but are not limited to omnidirectional light source or parallel light source, etc.; the material configuration includes but is not limited to flat plate configuration or spherical configuration, etc.

[0032] Further limitation, in S3, the total irradiation dose is converted into total irradiation fluence by using the empirical formula of the stopping power of the material to the charged particles; the empirical formula of the stopping power of the material to the charged particles is as follows:

[0033]

[0034] Wherein, D is the total irradiation dose, unit: Gy=J / kg; Φ is the total irradiation fluence, unit: pieces / cm 2 ; S / ρ is the stopping power, unit: MeV·cm 2 / g.

[0035] Further limitation, in step S3, the length and width of the material are both between 10mm-25mm, and the diameter The types of simulation software include but are not limited to MCNP, Cacino, Fastrad, Omere, etc.; the types of radiation source rays include but are not limited to omnidirectional light source or parallel light source, etc.; the material configuration includes but is not limited to flat plate configuration or spherical configuration, etc.

[0036] Further limited, the electron fluence rate range in step S5 is 1E+07-1E+10e / cm 2 / s.

[0037] Further limited, the proton fluence rate range in step S7 is 1E+07-1E+10p / cm 2 / s, and the single sample irradiation time is 15-30 minutes.

[0038] Further limited, the dosimeter type in step S8 includes but is not limited to alanine, GAFCHROMIC, GAFHD-V2, B3, etc.

[0039] The application provides an evaluation method for radiation shielding performance of a packaged and reinforced material and anti-radiation performance of an aerospace chip for deep space exploration. 60 The application proposes an electron-proton combined test method based on the ground test system conditions to restore the real deep space radiation environment of a spacecraft in orbit as much as possible, and is used for testing and evaluating the anti-radiation performance of the packaged and reinforced material and the anti-radiation performance of the chip, so as to solve the problem that the existing total dose effect evaluation method cannot evaluate the anti-radiation performance of the packaged and reinforced material and the anti-radiation performance of the chip in the deep space exploration radiation environment.

[0040] According to the evaluation method for the anti-radiation performance of the aerospace chip at present in China, the application proposes an electron-proton combined method for testing and evaluating the shielding performance and anti-radiation performance of the anti-radiation packaged and reinforced shielding material in the actual deep space exploration environment, so as to simulate the actual deep space exploration environment on the ground system as much as possible. The application is suitable for various types and reinforced radiation shielding materials, can reasonably guide the anti-radiation and anti-radiation performance test of the material in the simulated deep space environment on the ground, can also analyze the applicability of the shielding material in the deep space environment, and has the advantages of advancement, comprehensiveness and universality. The application can solve the problem that the current total dose effect test method cannot accurately reflect whether the electronic device meets the anti-radiation requirement in the actual radiation environment, guide the optimization of the anti-radiation packaging and reinforcement design of the product, and further improve the anti-radiation capability of the aerospace chip and ensure the on-orbit service stability.

[0041] In order to further understand the features and technical contents of the application, please refer to the following detailed description and drawings of the application. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 A schematic diagram of the overall process of the evaluation method of the radiation shielding performance of the deep space exploration packaging reinforced material and the anti-radiation performance of the spaceflight chip according to the present application is shown in the figure;

[0043] Figure 2 An electron total energy spectrum in the orbit environment of the JUICE according to the present application is shown in the figure;

[0044] Figure 3 A proton total energy spectrum in the orbit environment of the JUICE according to the present application is shown in the figure;

[0045] Figure 4 A schematic diagram of the material shielding performance test according to the present application is shown in the figure. DETAILED DESCRIPTION

[0046] The present application will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and are not used to limit the scope of the present application. The methods used in the examples are all conventional methods unless otherwise specified. Obviously, the described examples are part of the embodiments of the present application, but not all the embodiments.

[0047] This embodiment is described in detail taking the JUICE, a Jupiter system exploration mission planned by the European Space Agency with Jupiter III as the main exploration object, as an example. As shown in the figure, Figure 1 The evaluation method of the radiation shielding performance of the deep space exploration packaging reinforced material and the anti-radiation performance of the spaceflight chip according to the present application specifically includes the following steps:

[0048] (1) Orbit environment analysis

[0049] Before the start of the irradiation test, the energy composition and the proportion of each part of the radiation particles in the orbit environment of the JUICE are analyzed, and the electron differential flux energy spectrum and the proton differential flux energy spectrum in the orbit environment are obtained, as shown in the figures, Figure 2 and Figure 3

[0050] (2) Particle energy and flux analysis

[0051] Based on the differential flux energy spectrum results output by the orbit environment analysis, the type of the selected radiation particles and the accelerator are determined, the initial dose of each single energy in the energy spectrum in the single-layer silicon detector is calculated by using the simulation software, and the proportion of the irradiation dose of each single energy radiation source in the total dose of the energy spectrum is reasonably allocated.

[0052] Taking 3MeV electrons and 20MeV protons as examples, the initial doses contributed by them are 338.63 krad and 34184.01 krad, respectively.

[0053] (3) Conversion of the dose and fluence of the electrons and protons under single energy ​

[0054] The initial dose of single energy particles calculated by simulation software Cacino is the total irradiation dose at the time of testing at the single energy, and the total irradiation dose is converted into total irradiation fluence by using the empirical formula of the stopping power of silicon material to charged particles. The empirical formula of the stopping power of material to charged particles is as follows:

[0055]

[0056] Wherein, D is the total irradiation dose, unit: Gy = J / kg; Φ is the total irradiation fluence, unit: pieces / cm 2 ; S / ρ is the energy loss of charged particles in the material, also known as the stopping power, unit: MeV·cm 2 / g.

[0057] Taking 3MeV electrons and 20MeV protons as examples, their stopping powers S / ρ in silicon are 1.634MeV·cm 2 / g and 20.301MeV·cm 2 / g, respectively. The total irradiation fluences calculated by formula 1 are 1.295*10 13 e / cm 2 and 1.067*10 14 p / cm 2 , respectively.

[0058] (4) Material design and optimization

[0059] The total dose of radiation suffered by the space chip is set to be no more than 100krad, and the single-layer Al material is used as the packaging reinforcement shielding material. The simulation software Cacino is used to calculate the material thickness that meets the requirements, which is no less than 6mm.

[0060] (5) Electron irradiation test

[0061] The shielding material to be tested is placed on the sample table and fixed, and the chip to be tested is inserted into the test fixture. According to the calculation results of the total electron dose analysis, the shielding material and the chip are subjected to electron irradiation test at the corresponding dose, and the dose meter readings before and after the shielding material are recorded. After the electron irradiation test, the shielding material is subjected to low-temperature freezing treatment.

[0062] (6) Chip electrical signal test

[0063] The electrical signal test is performed on the chip after the electron irradiation test, and the data is collected. If the electrical signal is normal, the next test process is performed; if the electrical signal is not normal, it is determined that the shielding material cannot meet the anti-radiation requirements of the chip.

[0064] (7) Proton irradiation test

[0065] The chip with normal electrical signal and the packaging reinforced shielding material are further subjected to proton irradiation test. The shielding material to be tested is fixed on a sample table, and the chip to be tested is inserted into a test fixture. According to the calculation result of the total dose of protons, the shielding material and the chip are subjected to proton irradiation test at the corresponding dose, and the dose meter readings before and after the shielding material are read and recorded.

[0066] (8) Analysis and calculation of shielding performance of the material

[0067] After the proton irradiation test is completed, the shielding material performance test is completed, the dose before and after the material shielding is calibrated by using a GAFHD-V2 dose meter, the data are analyzed and the shielding performance is calculated, and a schematic diagram is shown in FIG. 4. Figure 4 The specific operation is as follows: the dose meters are placed before and after the shielding material sample, after irradiation, the dose meters will change color to different degrees according to the size of the irradiation dose, the absorbance of the dose meters is tested by using an ultraviolet-visible spectrophotometer, the test result is compared with a standard control table, the dose value absorbed by the dose meters before and after irradiation can be obtained, and thus the radiation shielding rate of the shielding material can be calculated to obtain the shielding performance of the material.

[0068] (9) Chip electrical signal test

[0069] The electrical signal of the chip after the electron and proton irradiation test is tested and data are collected. If the electrical signal is normal, the next test process is performed; if the electrical signal is not normal, it is determined that the shielding material cannot meet the anti-radiation requirement of the chip.

[0070] (10) Over-irradiation test and annealing treatment of the chip

[0071] The chip with normal electrical signal is continuously subjected to over-irradiation test with 50% increased dose, and the electrical signal of the chip is tested again after high-temperature annealing. If the test result is qualified, the irradiation test is completed.

[0072] (11) Evaluation of the anti-radiation performance of the chip

[0073] The change of the electrical signal is tested in situ to determine the running state of the chip, and the electrical signal of the chip without packaging and reinforcement is compared to determine the anti-radiation performance of the chip in the deep space radiation environment and the packaging and reinforcement effect of the shielding material on the chip.

[0074] The above describes in detail the specific embodiments of the present application for electrons and protons at a certain single energy, and does not have any limiting effect on other single energy particles, and can be analogously implemented.

Claims

1. A method for evaluating the radiation shielding performance of encapsulation and reinforcement materials for deep space exploration and the radiation resistance performance of aerospace chips, characterized in that, Includes the following steps: S1. Analyze the energy composition and proportion of each component of radiated particles under orbital conditions, and obtain the energy spectra of electrons and protons under orbital conditions respectively. S2. Based on the energy spectrum results of step S1, determine the types of radiation particles and accelerators to be selected, use simulation software to calculate the initial dose contributed by each single energy particle in the energy spectrum in the single-layer silicon detector, and reasonably allocate the proportion of the irradiation dose of each single energy radiation source in the total dose of the energy spectrum. S3. Use the initial dose obtained in S2 as the total irradiation dose for testing at a single energy level, and convert the total irradiation dose into total irradiation flux. S4. Based on the radiation resistance requirements of aerospace chips, design the elemental composition and component ratio of the encapsulation and reinforcement shielding material, and use simulation software to calculate the required shielding material thickness. S5. Place the shielding material to be tested on the sample stage and fix it. Insert the chip to be tested into the test fixture. According to the total electron dose analysis calculation results, conduct irradiation tests on the shielding material and the chip at the corresponding dose. Record the dosimeter readings before and after the shielding material is tested. After the electron irradiation test is completed, perform low-temperature freezing treatment on the shielding material. S6. Perform electrical signal testing on the chip after the irradiation test and collect data. If the electrical signal is normal, proceed to the next testing step. If the electrical signal is abnormal, it is determined that the shielding material cannot meet the chip's radiation resistance requirements. S7. Further proton irradiation tests are conducted on the chip with normal electrical signal and the packaging reinforcement shielding material. The shielding material to be tested is placed on the sample stage and fixed, and the chip to be tested is inserted into the test fixture. According to the total proton dose analysis and calculation results, the shielding material and the chip are subjected to proton irradiation tests at the corresponding doses. The dosimeter readings before and after the shielding material are read and recorded. S8. After the irradiation test is completed, the performance test of the shielding material is completed. The dose before and after shielding is calibrated using a dosimeter, the data is analyzed and the shielding performance is calculated. S9. Perform electrical signal testing on the chip after electron and proton irradiation tests and collect data. If the electrical signal is normal, proceed to the next testing step. If the electrical signal is abnormal, it is determined that the shielding material cannot meet the chip's radiation resistance requirements. S10. Continue to conduct an over-irradiation experiment with a 50% increased dose on the chip with normal electrical signal, and test the electrical signal of the chip again after high-temperature annealing. If the test result is qualified, the irradiation experiment ends. S11. By testing the changes in electrical signals in situ, the operating status of the chip is determined, and the electrical signals of the unencapsulated and hardened chip are compared to determine the radiation resistance of the chip in the deep space radiation environment and the encapsulation and hardening effect of the shielding material on the chip. In S1, the energy spectrum is the differential flux energy spectrum; In S2, the thickness of the single-layer silicon detector is 5 μm-80 μm; the simulation software is MCNP, Cacino, Fastrad, or Omere; the radiation source is an omnidirectional or parallel source; and the material configuration is a flat or spherical configuration. In S3, the total irradiation dose is converted into total irradiation flux using an empirical formula for the material’s ability to stop charged particles. The empirical formula for the ability of a material to stop charged particles is as follows: (1) in, D Total radiation dose, unit: Gy=J / kg; Φ Total irradiance, unit: cells / cm² 2 ; S / ρ To prevent this ability, the unit is: MeV•cm 2 / g; In S4, the length and width of the material are both between 10 mm and 25 mm, and the diameter is 10 mm < φ < 25 mm; the simulation software is MCNP, Cacino, Fastrad, or Omere; the radiation source is an omnidirectional light source or a parallel light source; and the material configuration is a flat plate configuration or a spherical configuration. In S5, the electron flux ratio ranges from 1E+0.7 to 1E+10 e / cm. 2 / s; In S7, the proton flux rate ranges from 1E+07 to 1E+10 p / cm. 2 / s, the irradiation time for a single sample is 15min-30min; In S8, the dosimeter types are alanine, GAFCHROMIC, GAFHD-V2, and B3; In S8, one dosimeter is placed before and after the shielding material sample. After irradiation, the dosimeter will change color to different degrees depending on the amount of irradiation dose received. The absorbance of the dosimeter is tested using an ultraviolet-visible spectrophotometer. The test results are compared with a standard reference table to obtain the dose value absorbed by the dosimeter before and after irradiation. From this, the radiation shielding rate of the shielding material can be calculated, and the shielding performance of the material can be obtained.

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