A method for induced radioactivity assessment applicable to mobile accelerator components

Abstract

The present application relates to the technical field of accelerator radiation protection, and particularly relates to a method for evaluating induced radioactivity suitable for mobile accelerator components; the method is characterized in that the activity concentration of radionuclides in different regions of the accelerator components before movement is calculated by using Monte Carlo simulation software, then the radionuclides are taken as radiation source terms, and the three-dimensional spatial dose rate distribution of the components and the periphery when the position of the accelerator components changes is calculated, so that the rapid evaluation of the dose received by the staff during maintenance and the rapid formulation of the maintenance scheme are realized. The method effectively promotes the application of the Monte Carlo method in the field of accelerator radiation protection, provides a reference for the radiation hazards received by the staff, and provides technical support for the radiation protection and operation and maintenance of the accelerator.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of accelerator radiation protection, and particularly relates to a method for evaluating induced radioactivity of a mobile accelerator component. TECHNICAL BACKGROUND

[0002] At present, when evaluating the induced radioactivity of an accelerator component, only the induced radioactivity of a fixed accelerator component, i.e., the induced radioactivity of the accelerator component after irradiation and with no change in position, can be evaluated, and the induced radioactivity of a mobile accelerator component, i.e., the induced radioactivity of the accelerator component after irradiation and with a change in position, cannot be evaluated.

[0003] In order to solve the above problems, the present application provides a method for evaluating the induced radioactivity of a mobile accelerator component. The method considers the operating conditions of the accelerator component, calculates the activity concentration of radionuclides in different regions of the accelerator component before movement by using Monte Carlo simulation software, then takes the radionuclides as a radiation source term, and calculates the three-dimensional spatial dose rate distribution of the component and the surrounding area when the position of the accelerator component changes, so as to realize the rapid evaluation of the dose received by the staff during maintenance and the rapid formulation of the maintenance scheme. The method solves the problem that the prior art cannot evaluate the induced radioactivity of a mobile accelerator component, i.e., the induced radioactivity of the accelerator component after irradiation and with a change in position. The method effectively promotes the application of the Monte Carlo method in the field of accelerator radiation protection, provides a reference for the radiation hazards received by the staff, and provides technical support for the radiation protection and operation and maintenance of the accelerator. SUMMARY

[0004] In view of the defects in the prior art, the present application provides a method for evaluating the induced radioactivity of a mobile accelerator component. The method considers the operating conditions of the accelerator component, calculates the activity concentration of radionuclides in different regions of the accelerator component before movement by using Monte Carlo simulation software, then takes the radionuclides as a radiation source term, and calculates the dose rate of the points of interest of the accelerator component after movement, so as to realize the evaluation of the induced radioactivity of the mobile accelerator component. The method effectively promotes the application of the Monte Carlo method in the field of accelerator radiation protection, and provides a reference for the radiation hazards received by the staff.

[0005] The technical scheme adopted by the present application is as follows: a method for evaluating the induced radioactivity of a mobile accelerator component, comprising the following steps:

[0006] S1, determining the operating conditions of the accelerator component: the operating conditions of the accelerator include beam adjustment, beam supply and maintenance. In order to meet the needs of different operating conditions, the accelerator component can be designed to be mobile. For a mobile accelerator component, the position of the mobile accelerator component is different under different operating conditions;

[0007] S2, constructing a geometric model and inputting parameters: using Monte Carlo simulation software to construct a geometric model, and inputting radiation source terms, running time and cooling time, to calculate radionuclide activity concentration distribution in three-dimensional space;

[0008] S3, selecting important areas: according to the radionuclide activity concentration distribution in each area, important areas are selected, and the radionuclide activity concentration of the area which induces radioactivity is higher and the volume is larger;

[0009] S4, re-constructing a geometric model for important areas: according to the radionuclide activity concentration distribution, the geometric model of important areas is partitioned, and areas with similar activity concentration are considered as one area.

[0010] S5, calculating radionuclide activity concentration: the radionuclide activity in each area of the new geometric model is calculated to obtain the radionuclide activity concentration in each area;

[0011] S6, selecting important radionuclides: the important radionuclides are radionuclides with a higher proportion of total radionuclide activity, and individual radionuclides with shorter half-lives and faster decay will also quickly disappear, which will contribute to the total radionuclide activity;

[0012] S7, constructing a geometric model after the accelerator component moves: a geometric model after the accelerator component moves is constructed according to the running condition of the accelerator component;

[0013] S8, calculating three-dimensional space dose rate distribution: taking a single area radionuclide as a radiation source term, the three-dimensional space dose rate distribution is calculated;

[0014] S9, calculating three-dimensional space total dose rate distribution: the dose rates generated by each radionuclide in each area are added to calculate the three-dimensional space total dose rate distribution;

[0015] S10, developing a maintenance plan: according to the three-dimensional space total dose rate distribution, the dose received by the staff during the maintenance of the Faraday cylinder and its shielding surface is evaluated, and a maintenance plan is developed.

[0016] Preferably, in step S1, the Faraday cylinder is used for measuring the intensity of the accelerator beam, and the running condition of the accelerator includes beam tuning, beam supply and maintenance. When the beam is tuned, the accelerator component is located at the beam line height, and when the beam is supplied, the accelerator component is lowered below the beam line.

[0017] Preferably, in step S2, the geometric model is a Faraday cylinder and its shielding, vacuum box, upstream magnet of the Faraday cylinder and downstream superconducting cavity constructed using Monte Carlo simulation software.

[0018] Preferably in step S2, the Monte Carlo simulation software is at least one of MCNPX or FLUKA, and the radiation source term includes the kind, energy, number, direction and position information of the beam loss particles.

[0019] Preferably in step S3, the important regions in the Faraday cup and its shielding are graphite region, copper region, tungsten region and lead region.

[0020] Preferably in step S4, the shape of the region is generally cylindrical, circular ring cylindrical and cuboid.

[0021] Preferably in step S5, the radionuclide activity in the 31 regions of the Faraday cup and its shielding is calculated.

[0022] Preferably in step S6, the radionuclide with a contribution greater than 0.5% to the total nuclide concentration and a half-life greater than 20 seconds is selected as an important radionuclide.

[0023] Preferably in step S7, the Faraday cup is moved to a position 15 cm below the beam line, and the positions of the Faraday cup shielding, the upstream magnet, the vacuum box and the downstream superconducting cavity are fixed.

[0024] Preferably in step S10, the maintenance of the staff at a distance of 30 cm from the upper lead shielding surface of the Faraday cup is considered; it can be obtained that the staff receives a dose rate of 0.6 mSv / h; according to the requirements of China Spallation Neutron Source for the dose control of radioactive staff during maintenance, the dose received by the staff in a quarter should not exceed 2.5 mSv, and the dose received by the staff in a year should not exceed 10 mSv; it can be obtained that the maintenance time of the staff: not more than 4.2 hours in a quarter, and not more than 16.8 hours in a year.

[0025] The beneficial effects of the present application are: the method for evaluating the induced radioactivity of the moving accelerator component provided by the present application has significant beneficial effects, the present application calculates the radionuclide activity concentration in different regions of the moving accelerator component by using Monte Carlo simulation software, then takes the radionuclide as a radiation source term, calculates the three-dimensional space dose rate distribution of the component and the surrounding when the position of the accelerator component changes, realizes the rapid evaluation of the dose received by the staff during maintenance and the rapid formulation of the maintenance scheme. The method effectively promotes the application of Monte Carlo method in the field of accelerator radiation protection, provides a reference for the radiation hazards received by the staff, and provides technical support for the radiation protection and operation and maintenance of the accelerator. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is the logical principle diagram of the present application;

[0027] Figure 2 is the geometric model diagram constructed by using the Monte Carlo simulation software in the present application;

[0028] Figure 3 is the Faraday cylinder and its shielding nuclide activity concentration distribution (unit: Bq / cm3) in the application;

[0029] Figure 4 is the geometric model diagram of the important area reconstructed in the application;

[0030] Figure 5 is the geometric model diagram of the accelerator component after moving in the application;

[0031] Figure 6 is the Faraday cylinder and its shielding dose rate distribution (unit: mSv / h) in the application;

[0032] Figure 7 is the Faraday cylinder and its shielding total dose rate distribution (unit: mSv / h) in the application. DETAILED DESCRIPTION

[0033] The application provides an induced radioactivity evaluation method suitable for a mobile accelerator component, which comprises the following steps:

[0034] S1, determining the operation condition of the accelerator component: the operation condition of the accelerator comprises beam adjustment, beam supply and maintenance, in order to meet the needs of different operation conditions, the accelerator component can be designed to be mobile, and the mobile accelerator component is located at different positions in different operation conditions;

[0035] S2, constructing a geometric model and inputting parameters: a geometric model is constructed by using Monte Carlo simulation software, and a radiation source term, an operation time and a cooling time are inputted, so that the nuclide activity concentration distribution of a three-dimensional space is calculated;

[0036] S3, selecting important areas: important areas are selected according to the nuclide activity concentration distribution in each area, and the important areas are areas with higher nuclide activity concentration and larger volume;

[0037] S4, reconstructing a geometric model for the important areas: the geometric model of the important areas is partitioned according to the nuclide activity concentration distribution, and areas with similar activity concentrations are considered as one area.

[0038] S5, calculating the nuclide activity concentration: the nuclide activity in each area of the new geometric model is calculated, so that the nuclide activity concentration in each area is obtained;

[0039] S6, selecting important radionuclides: the important radionuclides are radionuclides with high proportion of total radionuclide activity, and radionuclides with short half-life and fast decay are also considered, because their contribution to total radionuclide activity will disappear soon;

[0040] S7, constructing a geometric model of the accelerator component after movement: a geometric model of the accelerator component after movement is constructed according to the operating condition of the accelerator component;

[0041] S8, calculating a three-dimensional space dose rate distribution: a three-dimensional space dose rate distribution is calculated by taking radionuclides in a single region as a radiation source term;

[0042] S9, calculating a three-dimensional space total dose rate distribution: a three-dimensional space total dose rate distribution is calculated by adding dose rates generated by radionuclides in each region;

[0043] S10, formulating a maintenance scheme: a maintenance scheme is formulated according to the three-dimensional space total dose rate distribution to evaluate the dose received by a worker during maintenance of the Faraday cylinder and its shielding surface.

[0044] Preferably, in step S1, the Faraday cylinder is used for measuring the intensity of the accelerator beam, and the operating condition of the accelerator includes beam tuning, beam supply and maintenance, wherein the accelerator component is located at the beam line height during beam tuning, and the accelerator component is lowered below the beam line during beam supply.

[0045] Preferably, in step S2, the geometric model is a Faraday cylinder and its shielding, a vacuum box, a magnet upstream of the Faraday cylinder and a superconducting cavity downstream of the Faraday cylinder, which are constructed using Monte Carlo simulation software.

[0046] Preferably, in step S2, the Monte Carlo simulation software is at least one of MCNPX or FLUKA, and the radiation source term includes the type, energy, number, direction and position information of beam loss particles.

[0047] Preferably, in step S3, the important regions in the Faraday cylinder and its shielding are graphite regions, copper regions, tungsten regions and lead regions.

[0048] Preferably, in step S4, the shape of the region is generally a cylinder, a circular ring cylinder or a cuboid.

[0049] Preferably, in step S5, radionuclide activities in a total of 31 regions of the Faraday cylinder and its shielding are calculated.

[0050] Preferably, in step S6, radionuclides with a contribution greater than 0.5% to the total radionuclide concentration and a half-life greater than 20 seconds are selected as important radionuclides.

[0051] Preferably in step S7, the Faraday cylinder is moved to a position 15 cm below the beam line, and the Faraday cylinder shield, upstream magnet, vacuum box and downstream superconducting cavity are not moved.

[0052] Preferably in step S8, a radiation source term position sampling model is established, considering that the radionuclide activity concentration in a single region is uniformly distributed.

[0053] For a cylinder, the position sampling model is as follows:

[0054]

[0055] x = R cos (2πε3)

[0056] y = R sin (2πε3)

[0057] z = z1 + (z2-z1) ε4

[0058] wherein the z direction is the axial direction of the cylinder, (x, y, z) is the particle sampling position coordinate, R0 is the radius of the cylinder, z1 and z2 are the maximum z-axis coordinate and the minimum z-axis coordinate of the particle sampling, and ε1, ε2, ε3, ε4 are random numbers.

[0059] For a circular cylinder, the position sampling model is as follows:

[0060]

[0061] x = R cos (2πε4)

[0062] y = R sin (2πε4)

[0063] z = z1 + (z2-z1) ε5

[0064] wherein the z direction is the axial direction of the cylinder, (x, y, z) is the particle sampling position coordinate, R0 is the inner radius of the circular cylinder, R1 is the outer radius of the circular cylinder, z1 and z2 are the maximum z-axis coordinate and the minimum z-axis coordinate of the particle sampling, and ε1, ε2, ε3, ε4, ε5 are random numbers.

[0065] For a cuboid, the position sampling model is as follows:

[0066] x = x1 + (x2-x1) ε1

[0067] y = y1 + (y2-y1) ε2

[0068] z = z1 + (z2-z1) ε3

[0069] Wherein, (x, y, z) is the particle sampling position coordinates, x1 and x2 are the maximum x-axis coordinate and the minimum x-axis coordinate of the particle sampling, y1 and y2 are the maximum y-axis coordinate and the minimum y-axis coordinate of the particle sampling, z1 and z2 are the maximum z-axis coordinate and the minimum z-axis coordinate of the particle sampling, ε1, ε2, ε3 are random numbers;

[0070] When the radionuclide decays, the contribution of low-energy γ rays and β rays to the dose can be ignored compared with high-energy γ rays, and the contribution of γ rays with low emission probability to the dose can also be ignored, and the energy sampling model of the radiation source term can be obtained as follows:

[0071]

[0072] Wherein, P1, P2...P n-1 , P n , E1, E2...E n-1 , E n are the probability and energy of high-energy and high-emission-probability γ rays when the radionuclide decays, and ε is a random number;

[0073] The emitted γ rays are uniformly distributed in 4π solid angle, and the direction sampling model of the radiation source term can be obtained as follows:

[0074] u=sin(2πε1)·cos(2πε2)

[0075] v=sin(2πε1)·sin(2πε2)

[0076] w=cos(2πε1)

[0077] Wherein, (u, v, w) are the direction of the particle emission vector, and ε1, ε2 are random numbers;

[0078] The three-dimensional space dose rate distribution is divided into i*j*k cubic lattices by cutting the accelerator components and the periphery along the x-axis, y-axis and z-axis at fixed intervals, and the dose rate in each cubic lattice is calculated, wherein the x-axis direction is cut into i intervals, the y-axis direction is cut into j intervals, and the z-axis direction is cut into k intervals.

[0079] Preferably, in step S9, the dose rates generated by each radionuclide in each region are added to calculate the total three-dimensional space dose rate distribution:

[0080] D i,j,k =D1 i,j,k +D2 i,j,k +...+Dn i,j,k

[0081] Wherein, D i,j,kD1 is the total dose rate generated by each radionuclide in each region at the cubic lattice (i,j,k), Dn is the dose rate generated by each radionuclide in region 1 at the cubic lattice (i,j,k), i,j,k Dn is the dose rate generated by each radionuclide in region 1 at the cubic lattice (i,j,k), i,j,k Dn is the dose rate generated by each radionuclide in region 1 at the cubic lattice (i,j,k),

[0082] Preferably, in step S10, it is considered that the staff performs maintenance at a distance of 30 cm from the upper lead shielding surface of the Faraday cylinder; it can be obtained that the staff receives a dose rate of 0.6 mSv / h; according to the requirements of the Chinese Spallation Neutron Source for dose control of radioactive staff during maintenance, the dose received in a quarter is not more than 2.5 mSv, and the dose received in a year is not more than 10 mSv; it can be obtained that the maintenance time of the staff: not more than 4.2 hours in a quarter, and not more than 16.8 hours in a year.

[0083] Embodiment:

[0084] As shown in Figures 1-7 , the implementation of the method for evaluating induced radioactivity suitable for mobile accelerator components according to the embodiment specifically comprises:

[0085] S1, determine the operating condition of the accelerator component: the operating condition of the accelerator includes beam tuning, beam supply and maintenance. In order to meet the needs of different operating conditions, the accelerator component can be designed to be mobile. For the mobile accelerator component, when the beam is tuned, the Faraday cylinder is located at the beam line height, and when the beam is supplied and maintained, the Faraday cylinder is lowered to a position 15 cm below the beam line;

[0086] S2, as shown in Figures 2-3 , construct a geometric model and input parameters: use a Monte Carlo simulation software (one of FLUKA, MCNPX, etc.) to construct a geometric model, and input radiation source terms, operating time and cooling time. The calculated three-dimensional space radionuclide activity concentration distribution: the geometric model includes the Faraday cylinder and its shielding, the vacuum box, the magnet upstream of the Faraday cylinder and the superconducting cavity downstream of the Faraday cylinder; the operating time is 16 hours, and the cooling time is 1 hour; the constructed geometric model is as shown in Figure 2 ; the radionuclide activity concentration distribution of the Faraday cylinder and its shielding is as shown in Figure 3 ; the Faraday cylinder and its shielding are divided into 180*160*160 cubic lattices; among them, the x-axis direction is divided into 180 intervals, the y-axis direction is divided into 160 intervals, and the z-axis direction is divided into 160 intervals;

[0087] S3, selecting important regions: according to the radionuclide activity concentration distribution in each region, important regions are selected, and the radionuclide activity concentration and the volume of the important regions are higher; the important regions of the Faraday cylinder and its shielding are the graphite region, the copper region, the tungsten region and the lead region;

[0088] S4, as shown in the figure, the geometric model of the important region is reconstructed: according to the radionuclide activity concentration distribution, the geometric model of the important region is partitioned, and the regions with similar activity concentration are considered as one region. The shape of the region is generally cylindrical, circular ring cylindrical and cuboid. The graphite region is divided into four regions, including two cylindrical regions and two circular ring cylindrical regions. The copper region is divided into three regions, including two circular ring cylindrical regions and one cylindrical region. The tungsten region is divided into four regions, including two circular ring cylindrical regions and two cylindrical regions. The lead region is divided into 20 regions, including 20 cuboid regions. Figure 4

[0089] S5, calculating the radionuclide activity concentration: the radionuclide activity in each region of the new geometric model is calculated, and the radionuclide activity concentration in each region is obtained. The radionuclide activity of the Faraday cylinder and its shielding is calculated, and the total number of regions is 31.

[0090] S6, selecting important radionuclides: important radionuclides are radionuclides with high activity, and radionuclides with contribution greater than 0.5% and half-life greater than 20 seconds are selected as important radionuclides. For example, the important radionuclide activity in the graphite 1 region is shown in table 1.

[0091] Table 1 radionuclide activity in the graphite layer 1 region

[0092]

[0093]

[0094] S7, as shown in the figure, the geometric model of the accelerator component after moving is constructed: according to the running condition of the accelerator component, the geometric model of the accelerator component after moving is constructed, and the Faraday cylinder is moved to the position 15 cm below the beam line. The Faraday cylinder shielding, the upstream magnet, the vacuum box and the downstream part of the superconducting cavity are not moved. Figure 5

[0095] S8, calculating the three-dimensional space dose rate distribution: taking the radionuclide in a single region as the radiation source term, the three-dimensional space dose rate distribution is calculated. The Faraday cylinder and its shielding are divided into 45*40*40 cubes, wherein the x-axis direction is divided into 45 intervals, the y-axis direction is divided into 40 intervals, and the z-axis direction is divided into 40 intervals. The radionuclide activity concentration in the graphite 1 region is taken as the radiation source term, and the three-dimensional space dose rate distribution is calculated. 11 ​​C is an example, the calculated Faraday cylinder and its shielding dose rate distribution as shown in Figure 6

[0096] S9, as shown in Figure 7 The total dose rate distribution of three-dimensional space is calculated: the dose rate generated by each radionuclide in 31 regions is added, and the dose rate distribution of the Faraday cylinder and its shielding is calculated;

[0097] S10, develop maintenance program: according to the total dose rate distribution of three-dimensional space, the dose received by the staff when maintaining the Faraday cylinder and its shielding surface is evaluated, and the maintenance program is developed. Considering that the staff maintains at a distance of 30 cm from the upper lead shielding surface of the Faraday cylinder, the dose rate received by the staff is 0.6 mSv / h; According to the requirements of China Spallation Neutron Source for the dose control of radioactive staff during maintenance: at a distance of 30 cm from the surface of the equipment, the dose rate is 0.1-1 mSv / h, and the manual maintenance needs to control the time; The dose received by the staff in a quarter should not exceed 2.5 mSv, and the dose received by the staff in a year should not exceed 10 mSv; It can be obtained that the maintenance time of the staff is not more than 4.2 hours in a quarter and not more than 16.8 hours in a year.​

Claims

1. A method for assessing induced radioactivity suitable for use with mobile accelerator components, characterized by: The method comprises the following steps: S1, determining the operation condition of the accelerator component: the operation condition of the accelerator component comprises beam tuning, beam supply and maintenance, in order to meet the requirements of different operation conditions, the accelerator component is movable, and the position of the movable accelerator component is different under different operation conditions; S2, constructing a geometric model and inputting parameters: a Monte Carlo simulation software is used to construct a geometric model, and a radiation source term, an operation time and a cooling time are inputted, and a radionuclide activity concentration distribution in a three-dimensional space is calculated; S3, selecting important regions: important regions are selected according to the radionuclide activity concentration distribution in each region; S4, re-construction of the geometric model of the important regions: the geometric model of the important regions is partitioned according to the radionuclide activity concentration distribution, and regions with similar activity concentrations are considered as one region; S5, calculation of the radionuclide activity concentration: the radionuclide activity in each region in the new geometric model is calculated, and the radionuclide activity concentration in each region is obtained; S6, selection of important radionuclides: the important radionuclides are radionuclides with a higher proportion of radionuclide activity in the total radionuclide activity; S7, construction of the geometric model after the accelerator component is moved: a geometric model after the accelerator component is moved is constructed according to the operation condition of the accelerator component; S8, calculation of the three-dimensional space dose rate distribution: a single radionuclide in a single region is taken as a radiation source term, and a three-dimensional space dose rate distribution is calculated; S9, calculation of the three-dimensional space total dose rate distribution: the dose rates generated by radionuclides in each region are added, and a three-dimensional space total dose rate distribution is calculated; S10, development of a maintenance scheme: the dose received by a worker when maintaining the Faraday cylinder and the shielding surface thereof is evaluated according to the three-dimensional space total dose rate distribution, and a maintenance scheme is developed.

2. A method for assessing induced radioactivity suitable for components of a mobile accelerator according to claim 1, characterized in that: In step S1, the Faraday cylinder is used for measuring the beam intensity of the accelerator, and the operation condition of the accelerator comprises beam tuning, beam supply and maintenance, when the beam is tuned, the accelerator component is located at the height of the beam line, and when the beam is supplied, the accelerator component is lowered below the beam line.

3. A method for assessing induced radioactivity suitable for components of a mobile accelerator according to claim 1, characterized in that: In step S2, the geometric model is a Faraday cylinder and its shielding, a vacuum box, an upstream magnet of the Faraday cylinder and a downstream part of a superconducting cavity, which are constructed by using a Monte Carlo simulation software.

4. A method for assessing induced radioactivity suitable for components of a mobile accelerator according to claim 1, characterized in that: In step S2, the Monte Carlo simulation software is at least one of MCNPX or FLUKA, and the radiation source term comprises the type, energy, number, direction and position information of the beam loss particles.

5. A method for assessing induced radioactivity suitable for components of a mobile accelerator according to claim 1, characterized in that: In step S3, the important regions in the Faraday cylinder and the shielding thereof are graphite regions, copper regions, tungsten regions and lead regions.

6. A method for assessing induced radioactivity suitable for components of a mobile accelerator according to claim 1, characterized in that: In step S4, the shape of the regions is a cylinder, a circular ring cylinder or a cuboid.

7. A method for assessing induced radioactivity suitable for components of a mobile accelerator according to claim 1, characterized in that: In step S5, the radionuclide activity in a total of 31 regions of the Faraday cylinder and the shielding thereof is calculated.

8. A method for assessing induced radioactivity suitable for components of a mobile accelerator according to claim 1, characterized in that: In step S6, radionuclides with a contribution of greater than 0.5% to the total radionuclide concentration and a half-life of greater than 20 seconds are selected as important radionuclides.

9. A method for assessing induced radioactivity suitable for components of a mobile accelerator according to claim 1, characterized in that: In step S7, the Faraday cylinder is considered to be moved to a position 15 cm below the beam line, and the positions of the Faraday cylinder shielding, the upstream magnet, the vacuum box and the downstream part of the superconducting cavity are unchanged.

10. A method for assessing induced radioactivity suitable for components of a mobile accelerator according to claim 1, characterized in that: In step S10, the worker performs maintenance at a specific position on the surface of the lead shield of the upper part of the Faraday cylinder, and the dose rate to which the worker is exposed is obtained. Then, based on the dose control requirement when the worker is performing maintenance, the worker's maintenance time is obtained.

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