Gamma irradiation medium module and dose field testing and analysis method

Abstract

The application discloses a kind of gamma irradiation medium modules, including irradiation container and the several medium modules being arranged in irradiation container, irradiation container and medium module are cuboid structure;The length and height of single medium module are slightly less than the length and height of irradiation container one third respectively, the width of single medium module is slightly less than the width of irradiation container;The number of all medium modules=the number of medium module in full load in irradiation container * irradiation station number, irradiation station is used to place irradiation container;A dose field test and analysis method for gamma irradiation medium module is also disclosed.The application clearly medium module in irradiation container in loading mode and related parameters such as radiation safety, clearly irradiation device dose field is carried out mathematical simulation, the establishment of OQ dose field test coordinate system, dose meter is laid out mesh and point, the analysis use method of actual measurement dose data, provides proof data and technical basis, effectively improves core technical ability and quality assurance ability.

Description

Technical Field

[0001] The present invention relates to a gamma irradiation device equipment operation process technology, and in particular to an irradiation medium module for dose field testing during equipment operation identification, and a dose field testing and analysis method. Background Art

[0002] The installation and commissioning of the gamma irradiation device and each change of the installation to increase or decrease the cobalt source must be subject to equipment operation qualification (OQ) in accordance with the requirements of GB / T17568-2019 standard to obtain data to prove that when the irradiation device is used and operated in accordance with the equipment operation procedure, the installed irradiation device is operating within the predetermined equipment operation technical parameters and the irradiated medium reaches the irradiation dose range set by the irradiation process, thereby improving the accuracy, repeatability and traceability of the irradiation process dose control, especially playing a role in technical guarantee and quality assurance of process control for ensuring the disinfection, sterilization and sterility assurance level of medical products.

[0003] The data to be obtained for the equipment operation qualification of the irradiation device should at least include the dose distribution test data in the irradiation container, the distribution law diagram of the isodose curve, the maximum dose value and the equivalent area, the minimum dose value and the equivalent area, the dose unevenness DUR, the main control time MT parameter, the coordinate point position of the dosimeter, the cobalt source utilization rate SER, the processing capacity PT and other data.

[0004] The products irradiated and processed by industrial gamma irradiation equipment cover the medical device, electrical, chemical, pharmaceutical, food and other industries. The physical and chemical properties of the products are different. The material states include solid, liquid, semi-solid, etc. The material properties include metals, semiconductors, polymers, non-woven fabrics, etc. The product density range is large, and the density and distribution of the product are key input items in the irradiation processing technology design. Therefore, in the operation identification process, it is necessary to seek an irradiation medium module that can represent the density and distribution of all products to be irradiated to conduct operation identification dose field testing to obtain the expected certification data, and to be economically reasonable, technically feasible, safe and environmentally friendly. It can avoid a large amount of economic waste caused by using the products to be irradiated for operation identification, and can also representatively cover the density and distribution of all products to be irradiated. In the operation identification, carrying the irradiation dose as an irradiation medium is one of the necessary conditions for the dose field testing process. The determination of whether the irradiation medium, which is the carrier of the irradiation dose during the operation identification dose field test, can meet the irradiation process requirements, represent the relevant parameters of the irradiation dose absorbed by all products to be irradiated, and conduct dose field testing and mathematical analysis in a systematic way is a key link in the operation identification process of irradiation equipment and is also one of the difficulties. Summary of the Invention

[0005] In view of the problems in the prior art, the gamma irradiation medium module and the dose field testing and analyzing method are provided, and the mathematical model of the ray transmission of the irradiation device is established by using the Monte Carlo method, the three-dimensional array dose absorption result of the irradiation container of the irradiation device is calculated, the contour maps of the absorption dose of the A, C and E surfaces are formed according to the results of the three representative profile absorption doses, the distribution of the maximum and minimum profile absorption doses of the irradiation container is vividly reflected, and meanwhile, a theoretical basis is provided for the arrangement of the dosimeters in the expected minimum and maximum dose areas in the dose distribution test of the product.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is:

[0007] The gamma irradiation medium module comprises an irradiation container and a plurality of medium modules arranged in the irradiation container, and the irradiation container and the medium modules are all cuboid structures.

[0008] The length and height of a single medium module are slightly smaller than one third of the length and height of the irradiation container respectively, and the width of a single medium module is slightly smaller than the width of the irradiation container.

[0009] The number of all the medium modules = the number of the medium modules fully loaded in the irradiation container * the number of irradiation stations, and the irradiation station is used to place the irradiation container.

[0010] To solve the technical problems, the further technical scheme adopted by the present application is:

[0011] Further, the length, width and height of a single medium module are 390 mm, 585 mm and 460 mm respectively, and the length, width and height of the irradiation container are 1200 mm, 600 mm and 1400 mm respectively.

[0012] Further, the medium module comprises a module inner core and a module outer box, the module inner core is a low-density inner core, a medium-density inner core or a high-density inner core, the material of the module inner core is wooden honeycomb paperboard, corrugated paperboard + medium-density board or corrugated paperboard + high-density board, and the module outer box is a wooden corrugated paper box.

[0013] Further, the medium module is a homogeneous medium module, the density range of the medium module is 0.02-0.35 g / cm 3 , and the density tolerance of the medium module is ±1.5%.

[0014] Further, the density of the medium module is 0.02 g / cm 3 , 0.20 g / cm 3and 0.35 g / cm 3 at least one of the following.

[0015] Further, when the module inner core of the medium module adopts a low-density inner core and the material of the module inner core adopts wooden honeycomb paperboard, the density of the medium module is 0.02 g / cm 3 ; when the module inner core of the medium module adopts a medium-density inner core and the material of the module inner core adopts corrugated paperboard + medium-density board, the density of the medium module is 0.20 g / cm 3 ; when the module inner core of the medium module adopts a high-density inner core and the material of the module inner core adopts corrugated paperboard + high-density board, the density of the medium module is 0.35 g / cm 3 .

[0016] The application further provides a dose field test and analysis method for gamma irradiation medium modules, and the dose field test and analysis method comprises the following steps:

[0017] S1: establishing a dose field test coordinate system;

[0018] S2: running the medium module in the irradiation room dose field;

[0019] S3: confirming the suitability of the coordinate system and the dosimeter and the arrangement grid point position by simulating the dose field distribution mathematical model through Monte Carlo;

[0020] S4: medium module dose field test data analysis and dose field test result confirmation;

[0021] S5: calculating and analyzing the dose non-uniformity DUR, irradiation master control time MT, processing capacity PT and cobalt source utilization rate SER to determine whether the receiving standard requirements are met.

[0022] In order to solve the technical problems of the method, the further technical scheme adopted by the application is:

[0023] Further, in S1, the XYZ three-dimensional coordinate system is established with the irradiation container as a unit, the Z coordinate axis direction is divided into 100 mm scale units, the X coordinate axis direction is divided into 150 mm scale units, and the Y coordinate axis direction is divided into 300 mm scale units, thereby establishing a 150*300*100 grid three-dimensional coordinate system.

[0024] In the three-dimensional coordinate system, the scale points in the X-axis direction are set to be A, B, C, D, and E, and the planes where the scale points A, B, C, D, and E are located are parallel to the Y-axis. The plane where the scale point A is located is defined as the A plane, the plane where the scale point C is located is defined as the C plane, and the plane where the scale point E is located is defined as the E plane. The irradiation dose is highest on the A plane and the E plane along the vertical direction of the cobalt source plate of the irradiation container, and lowest on the C plane of the center line of the irradiation container. The A plane and the C plane with the highest irradiation dose and the E plane with the lowest irradiation dose are selected as the measurement planes for dose measurement.

[0025] Furthermore, in S2, the medium module is operated in a roller conveyor double-layer, two-way, four-channel automatic layer and cover changing cargo source mode. In the irradiation chamber dose field test, the medium module enters the irradiation chamber in a fully loaded mode in the irradiation container according to the PLC control program and action instructions to receive irradiation.

[0026] Furthermore, in S3, a mathematical model of the radiation transmission of the irradiated container is established by the Monte Carlo method, and the dose absorption results of the three-dimensional array of the irradiated container are calculated. Based on the absorbed dose results of the A-surface, C-surface and E-surface, contour cloud maps of the absorbed dose of the A-surface, C-surface and E-surface are formed to reflect the distribution of the maximum and minimum cross-sectional absorbed doses of the irradiated container and provide a theoretical basis for the placement of dosimeters in the expected minimum and maximum dose areas in the dose distribution test of the product;

[0027] Low-density, medium-density, and high-density dielectric modules were used for operational dose field testing. The dose field distribution mathematical model was verified by arranging dose meters for dose measurement. The dose meters used were calibrated potassium dichromate or silver dichromate dosimeters with a range of 5.0 to 40.0 kGy. The dosimeters were arranged on all corresponding coordinate grid points in the A, C, and E surface coordinate systems. After removal from the irradiation, the dosimeters were tested using a certified ultraviolet spectrophotometer. The absorbance of the dosimeters was read and the absorbed dose at each point was calculated.

[0028] Furthermore, in S4, the actual data of the dose field test is collected, analyzed and processed according to the ISO / ASTM 52303:2015 standard to form a dose field test data table;

[0029] The data analysis and calculation process is as follows:

[0030] Definition D iz is the dose measured by the dose meter at the z dose point for the i-th time. Nz independent measurements are performed in the z dose area. The average dose at each z dose point is Average (D z ) is calculated using the following formula:

[0031]

[0032] The dose measurement variance S of the mean at each dose point z 2 is calculated by the following equation:

[0033]

[0034] The dose variability of each dose region with respect to the mean is considered to be similar, then the variance S of the whole dose field is overall calculated by the following equation:

[0035]

[0036] where: Average(D z ) is the dose mean; Z total is the total number of dose regions; N is the total number of dose tests;

[0037] When the mean of a dose region is equal to the mean of the whole dose field, then this region is the equivalent minimum dose region;

[0038] When the mean of a dose region is equal to the mean of the whole dose field, then this region is the equivalent maximum dose region;

[0039] where δ is the minimum discrimination factor, δ is calculated by the following equation:

[0040]

[0041] where: k is the coverage factor; S 2 overall is the within-group variance; average(n z ) is the average number of independent measurements in each dose region;

[0042] The dose uniformity ratio DUR is the ratio of the maximum absorbed dose D max to the minimum absorbed dose D min :

[0043] DUR = D max / D min

[0044] The maximum coefficient of variation CV of each dose region is the ratio of the standard deviation of each dose region to the mean:

[0045] CV = S z / Average(D z )

[0046] The maximum and minimum equivalent dose regions simulated are compared with the dose distribution measured by the dosimeter tests arranged by the medium module to determine whether they are consistent, verifying the accuracy of the Monte Carlo method used for dose distribution testing.

[0047] Further, in S5,

[0048] First, the dose uniformity DUR is analyzed:

[0049] According to the comparison of the calculated dose uniformity DUR and the standard DUR, it is judged whether the change of the dose uniformity after the cobalt source is changed is within the acceptable standard range;

[0050] Secondly, the irradiation master control time MT is analyzed:

[0051] According to the dose distribution test data, the variation coefficient, the relative deviation and the adjustment coefficient of the minimum absorbed dose of the given irradiation master control time and the required minimum absorbed dose of the low-density, medium-density and high-density simulation medium modules are analyzed, and it is determined whether the master control time adjustment coefficient after the cobalt source is changed is appropriate;

[0052] Then, the processing capacity PT of the irradiation device is analyzed:

[0053] According to the dose distribution test data, the processing capacity PT of the low-density, medium-density and high-density simulation medium modules is calculated at the minimum absorbed dose of 25kGy under the cobalt source of 1 million curie activity of the irradiation device, and the processing capacity PT is compared with the standard PT to determine the change of the processing capacity PT after the cobalt source is changed;

[0054] Finally, the cobalt source utilization rate SER is analyzed:

[0055] According to the result data of the dose distribution test, the cobalt source utilization rate SER value of the low-density, medium-density and high-density simulation medium modules is calculated, and is compared with the SER value of the design standard of the irradiation device to measure the cobalt source utilization rate level.

[0056] The beneficial effects of the present application are:

[0057] 1. The application of the medium module and its N loading combinations in the present invention effectively replaces the existing practice of some unbalanced, unstable, and environmentally unfriendly test irradiation medium modules. At the same time, it provides a method for selecting a dosimeter, simulating a Monte Carlo dose field mathematical model, establishing a unit coordinate system, an OQ dose field test process, comprehensive data analysis, mathematical calculation of the minimum discrimination factor, equivalent maximum dose area and equivalent minimum dose area, and obtaining technical parameters such as dose unevenness DUR, irradiation master control time MT, processing capacity PT, and cobalt source utilization rate SER. The application of the present invention achieves the purpose of accurately obtaining dose field data and mastering the dose field distribution law, systematically forms and provides the general method, main content, analysis elements and parameters of dose field testing, provides technical support for irradiation processing technology design and precise control of irradiation dose range, and also greatly improves the core technology level of the irradiation plant. The component material of the medium module is mainly wooden green, environmentally friendly and reusable products, avoiding the pollution and waste caused by the previous use of other alternative products such as polystyrene EPS and other chemical products;

[0058] Second, the present invention establishes a mathematical model of ray transmission in an irradiation device through the Monte Carlo method, calculates the dose absorption results of a three-dimensional array of irradiated containers in the irradiation device, and forms contour cloud maps of the absorbed doses on the A, C, and E surfaces based on the absorbed dose results of the three representative sections. This vividly reflects the distribution of the maximum and minimum absorbed doses of the irradiated containers, and also provides a theoretical basis for arranging dosimeters in the expected minimum and maximum dose areas in the dose distribution test of the product.

[0059] 3. The present invention not only provides a safe, environmentally friendly and reusable dose field test medium module for the irradiation plant, but also provides a process and mathematical analysis method for realizing the dose field test of the gamma irradiation device through this module. It clarifies the density, material, specifications, loading mode of the medium module in the irradiation container and radiation safety and other related parameters in actual operation. It also clarifies the application of the Monte Carlo method to mathematically simulate the dose field of the irradiation device, the establishment of the OQ dose field test coordinate system, the dosimeter layout grid and point position, and the analysis and use of the measured dose data. It provides certification data to meet the requirements of the GB / T17568-2019 standard, and also provides a series of technical basis for the process design and production operation control of the irradiation device, effectively improving the core technical capabilities of the irradiation plant and the quality assurance capabilities of radiation processing such as disinfection and sterilization of medical products and medical devices.

[0060] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is a schematic diagram of the structure and dimensions of the medium module and the medium module fully loaded in the irradiation container according to the present invention;

[0062] Figure 2 The core of the module of the present invention is 0.20g / cm 3 Schematic diagram of the assembly of the dielectric module with a low-density inner core;

[0063] Figure 3 The core of the module of the present invention is 0.20g / cm 3 Medium density inner core and 0.35g / cm 3 Schematic diagram of the assembly of the dielectric module with a high-density inner core;

[0064] Figure 4 is a schematic diagram of the dose field test coordinate system of the present invention;

[0065] Figure 5 It is the irradiation path diagram of the irradiation container station of the present invention;

[0066] Figure 6 It is 0.20g / cm 3 The medium module simulates the dose distribution map using the Monte Carlo method;

[0067] Figure 7 It is the mathematical model for simulating dose field using the Monte Carlo method described in the present invention;

[0068] Figure 8 It is the OQ dose field test mathematical model of the present invention;

[0069] Figure 9 This is a flow chart of a dose field testing and analysis method for a gamma irradiated medium module according to the present invention;

[0070] The parts in the accompanying drawings are marked as follows:

[0071] Irradiation container 1 , media modules 2 , length a of a single media module, width b of a single media module, height h of a single media module, length a′ of irradiation container, width b′ of irradiation container and height h′ of irradiation container. DETAILED DESCRIPTION

[0072] The following describes the specific embodiments of the present invention through specific examples. Those skilled in the art will readily understand the advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented in various other forms, i.e., various modifications and variations are possible without departing from the scope of the present invention.

[0073] Example 1:

[0074] A gamma irradiation medium module, such as Figures 1-3 As shown, it includes an irradiation container 1 and a plurality of medium modules 2 arranged in the irradiation container, and both the irradiation container and the medium modules are rectangular parallelepiped structures;

[0075] The length a and height h of a single medium module are slightly smaller than one-third of the length a' and height h' of the irradiation container, respectively; the width b of a single medium module is slightly smaller than the width b' of the irradiation container;

[0076] The total number of media modules = the number of fully loaded media modules in the irradiation container * the number of irradiation stations, where the irradiation stations are used to place the irradiation containers.

[0077] The length, width and height of a single medium module are 390mm, 585mm and 460mm respectively, and the length, width and height of the irradiation container are 1200mm, 600mm and 1400mm respectively.

[0078] The medium module includes a module core and a module outer box. The module core is a low-density core, a medium-density core or a high-density core. The material of the module core is wooden honeycomb cardboard, corrugated cardboard + medium-density board or corrugated cardboard + high-density board. The module outer box is a wooden corrugated box.

[0079] The medium module is a homogeneous medium module with a density range of 0.02-0.35g / cm 3 , the density tolerance of the dielectric module is ±1.5%.

[0080] The density of the dielectric module is 0.02g / cm 3 , 0.20g / cm 3 and 0.35g / cm 3 At least one of .

[0081] When the inner core of the medium module adopts a low-density inner core and the material of the inner core of the medium module adopts a wood honeycomb paperboard, the density of the medium module is 0.02g / cm 3 When the core of the medium module is a medium-density core and the core material is corrugated cardboard + medium-density fiberboard, the density of the medium module is 0.20 g / cm 3 When the core of the media module is made of high-density core and the core material is made of corrugated cardboard + high-density board, the density of the media module is 0.35g / cm 3 .

[0082] Example 2:

[0083] A dose field testing and analysis method for gamma irradiated medium modules, such as Figures 4-9 As shown, the dose field testing and analysis method includes the following steps:

[0084] S1: Establishing a dose field test coordinate system;

[0085] S2: Running the medium module in the irradiation chamber dose field;

[0086] S3: Confirming the suitability of the coordinate system and the dosimeter and its arrangement grid points by Monte Carlo simulation dose field distribution mathematical model;

[0087] S4: Medium module dose field test data analysis and dose field test results confirmation;

[0088] S5: Calculating and analyzing the dose non-uniformity DUR, irradiation master control time MT, processing capacity PT and cobalt source utilization rate SER to determine whether to meet the receiving standard requirements.

[0089] In S1, an XYZ three-dimensional coordinate system is established with the irradiation container as a unit, the Z coordinate axis is divided into 100mm scale units, the X coordinate axis is divided into 150mm scale units, and the Y coordinate axis is divided into 300mm scale units, establishing a 150*300*100 grid three-dimensional coordinate system;

[0090] In the three-dimensional coordinate system, the X axis direction scale points are A, B, C, D and E, the faces where the scale points A, B, C, D and E are located are parallel to the Y coordinate axis, the face where the scale point A is located is defined as the A face, the face where the scale point C is located is defined as the C face, and the face where the scale point E is located is defined as the E face. The dose is the highest in the A face and the E face of the irradiation container along the vertical direction of the cobalt source plate, and the dose is the lowest in the C face of the center line of the irradiation container. The A face, C face and E face with the highest dose are selected as the measurement planes for dose measurement.

[0091] In S2, the medium module is run by adopting the operation mode of automatic layer and surface changing of double-layer double-direction four-channel goods cover source by roller conveyor. In the irradiation chamber dose field test, the medium module enters the irradiation chamber according to the PLC control program and action instructions in the full load mode to receive irradiation.

[0092] In S3, a mathematical model of ray transmission of the irradiation container is established by Monte Carlo method, the three-dimensional array dose absorption result of the irradiation container is calculated, and the contour maps of the A face, C face and E face absorption dose are formed according to the results of the A face, C face and E face absorption dose, to reflect the distribution of the maximum and minimum cross-section absorption dose of the irradiation container and provide a theoretical basis for the arrangement of the dosimeter in the expected minimum and maximum dose area in the product dose distribution test;

[0093] Low-density, medium-density, and high-density dielectric modules were used for operational dose field testing. The dose field distribution mathematical model was verified by arranging dose meters for dose measurement. The dose meters used were calibrated potassium dichromate or silver dichromate dosimeters with a range of 5.0 to 40.0 kGy. The dosimeters were arranged on all corresponding coordinate grid points in the A, C, and E surface coordinate systems. After removal from the irradiation, the dosimeters were tested using a certified ultraviolet spectrophotometer. The absorbance of the dosimeters was read and the absorbed dose at each point was calculated.

[0094] In S4, according to ISO / ASTM 52303:2015 standard, the actual data of the dose field test is collected, analyzed and processed to form a dose field test data table;

[0095] The data analysis and calculation process is as follows:

[0096] Definition D iz is the dose measured by the dose meter at the z dose point for the i-th time. Nz independent measurements are performed in the z dose area. The average dose at each z dose point is Average (D z ) is calculated using the following formula:

[0097]

[0098] At each dose point, the dose measurement variance S of the mean z 2 , calculated using the following formula:

[0099]

[0100] The dose variability of each dose region about the mean is considered to be similar, and the variance S of the entire dose field is overall Calculated using the following formula:

[0101]

[0102] Among them: Average(D z ) is the average dose; Z total is the total number of dose areas; N is the total number of dose tests;

[0103] When the average value of the dose area Then this area is the equivalent minimum dose area;

[0104] When the average value of the dose area Then this area is the equivalent maximum dose area;

[0105] Among them, δ is the minimum discrimination factor, which is calculated by the following formula:

[0106]

[0107] wherein: k is a coverage factor; S 2 overall is the variance within the group; average(n z ) is the average number of independent measurements in each dose region;

[0108] Dose uniformity DUR is the ratio of the maximum absorbed dose D max to the minimum absorbed dose D min

[0109] DUR = D max / D min

[0110] The maximum coefficient of variation CV for each dose region is the ratio of the standard deviation to the average for each dose region:

[0111] CV = S z / Average(D z )

[0112] The maximum and minimum isodose regions from the simulation are compared to the dose distribution determined from the dosimeter test to determine if they are consistent, verifying the accuracy of the Monte Carlo method used for the dose distribution test.

[0113] In S5,

[0114] First, the dose uniformity DUR is analyzed:

[0115] The calculated dose uniformity DUR is compared to the standard DUR to determine if the change in dose uniformity after the cobalt source change is within the acceptable standard;

[0116] Second, the irradiation master time MT is analyzed:

[0117] The coefficient of variation, relative deviation, and adjustment factor of the minimum absorbed dose given the irradiation master time for the low-density, medium-density, and high-density simulated medium modules are analyzed according to the dose distribution test data to determine if the master time adjustment factor after the cobalt source change is appropriate;

[0118] Then, the irradiation device processing capacity PT is analyzed:

[0119] The processing capacity PT in cubic meters per hour of the low-density, medium-density, and high-density simulated medium modules at a minimum absorbed dose of 25 kGy under the 1 million curie activity of the cobalt source of the irradiation device is calculated according to the dose distribution test data, and compared to the standard PT to determine the change in processing capacity PT after the cobalt source change; ​

[0120] Finally, the cobalt source utilization rate SER is analyzed:

[0121] According to the result data of the dose distribution test, the cobalt source utilization rate SER values of the low-density, medium-density and high-density simulation medium modules are calculated, and compared with the SER values of the irradiation device design standard, so as to measure the cobalt source utilization rate level.

[0122] The above is only an embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or direct or indirect application in other related technical fields based on the content of the present application specification and drawings is also included in the patent protection scope of the present application.

Claims

1. A dose field testing and analysis method for a gamma irradiated medium module, characterized by: The dose field testing and analysis method comprises the following steps: S1: Establish the dose field test coordinate system; S2: Run the medium module in the dose field of the irradiation chamber; S3: Use MCNP to simulate the dose field distribution mathematical model and confirm the suitability of the coordinate system, dosimeters and their grid points. S4: Dielectric module dose field test data analysis and dose field test results confirmation; S5: Calculate and analyze the dose unevenness DUR, irradiation master time MT, processing capacity PT and cobalt source utilization rate SER to determine whether they meet the acceptance standard requirements; In S1, an XYZ three-dimensional coordinate system is established with the irradiation container as a unit, the Z coordinate axis is equally divided into scale units of 100 mm, the X coordinate axis is equally divided into scale units of 150 mm, and the Y coordinate axis is equally divided into scale units of 300 mm, and a three-dimensional coordinate system with a grid size of 150*300*100 is established; In a three-dimensional coordinate system, the scale points in the X-axis direction are set as A, B, C, D, and E respectively. The planes where the scale points A, B, C, D, and E are located are parallel to the Y-axis. The plane where the scale point A is located is defined as the A plane, the plane where the scale point C is located is defined as the C plane, and the plane where the scale point E is located is defined as the E plane. The irradiation dose is highest on the A plane and the E plane perpendicular to the cobalt source plate of the irradiation container, and lowest on the C plane of the center line of the irradiation container. The A plane and the C plane with the highest irradiation dose and the E plane with the lowest irradiation dose are selected as the measurement planes for dose measurement. In S3, a mathematical model of the radiation transmission of the irradiated container is established using the Monte Carlo method, and the dose absorption results of the three-dimensional array of the irradiated container are calculated. Based on the absorbed dose results of the A-surface, C-surface, and E-surface, contour cloud maps of the absorbed dose of the A-surface, C-surface, and E-surface are formed to reflect the distribution of the maximum and minimum cross-sectional absorbed doses of the irradiated container and provide a theoretical basis for the placement of dosimeters in the expected minimum and maximum dose areas in the dose distribution test of the product; Low-density, medium-density, and high-density dielectric modules were used for operational dose field testing. The dose field distribution mathematical model was verified by arranging dose meters for dose measurement. The dose meters used were calibrated potassium dichromate or silver dichromate dosimeters with a range of 5.0 to 40.0 kGy. The dosimeters were arranged on all corresponding coordinate grid points in the A, C, and E surface coordinate systems. After removal from the irradiation, the dosimeters were tested using a certified ultraviolet spectrophotometer. The absorbance of the dosimeters was read and the absorbed dose at each point was calculated.

2. The dose field testing and analysis method for a gamma irradiation medium module according to claim 1, characterized in that: In S2, the medium module is operated in a roller conveyor double-layer, two-way, four-channel automatic layer and cover changing cargo source mode. In the irradiation chamber dose field test, the medium module enters the irradiation chamber in a fully loaded mode in the irradiation container according to the PLC control program and action instructions to receive irradiation.

3. The dose field testing and analysis method for a gamma irradiation medium module according to claim 1, characterized in that: In S4, according to ISO / ASTM 52303:2015 standard, the actual data of the dose field test is collected, analyzed and processed to form a dose field test data table; The data analysis and calculation process is as follows: Definition D iz is the dose measured by the dose meter at the z dose point for the i-th time. Nz independent measurements are performed in the z dose area. The average dose at each z dose point is Average (D z ) is calculated using the following formula: At each dose point, the dose measurement variance S of the mean z 2 , calculated using the following formula: The dose variability of each dose region about the mean is considered to be similar, and the variance S of the entire dose field is overall Calculated using the following formula: Among them: Average(D z ) is the average dose; Z total is the total number of dose areas; N is the total number of dose tests; When the average value of the dose area Then this area is the equivalent minimum dose area; When the average value of the dose area Then this area is the equivalent maximum dose area; Among them, δ is the minimum discrimination factor, which is calculated by the following formula: Where: k is the coverage factor; S 2 overall is the variance within the group; average(n z ) is the average number of independent measurements in each dose area; Dose unevenness DUR is the maximum absorbed dose D max and minimum absorbed dose D min The ratio of: HARD=D max / D min The maximum coefficient of variation (CV) for each dose region is the ratio of the standard deviation to the mean value for each dose region: CV=S z / Average(D z ) The accuracy of the Monte Carlo method used in the dose distribution test was verified by comparing the simulated maximum and minimum equal dose areas with the dose distribution obtained by the medium module arrangement dose meter test to determine their consistency.

4. The dose field testing and analysis method for a gamma irradiation medium module according to claim 1, characterized in that: In S5, First, the dose unevenness DUR is analyzed: Compare the calculated dose unevenness DUR with the standard DUR to determine whether the dose unevenness change after the cobalt source is changed is within the acceptable standard range; Secondly, analyze the irradiation master control time MT: Based on the dose distribution test data, the coefficient of variation, relative deviation, and adjustment factor of the minimum absorbed dose at a given irradiation master control time of the low-density, medium-density, and high-density simulated medium modules and the required minimum absorbed dose are analyzed to determine whether the master control time adjustment factor after the cobalt source is changed is appropriate; Then, the PT analysis of the irradiation device processing capability is carried out: Based on the dose distribution test data, the processing capacity (PT) of low-density, medium-density, and high-density simulated dielectric modules at a minimum absorbed dose of 25 kGy under a cobalt source activity of 1 million Curies in the irradiation device was calculated in cubic meters per hour. This was compared with the standard PT to determine the change in processing capacity (PT) after the cobalt source was changed. Finally, the cobalt source utilization rate SER is analyzed: Based on the results of the dose distribution test, the cobalt source utilization rate SER values ​​of the low-density, medium-density and high-density simulated dielectric modules were calculated and compared with the SER values ​​of the irradiation device design standards to measure the cobalt source utilization level.

5. The dose field testing and analysis method for a gamma irradiation medium module according to claim 1, characterized in that: It also includes an irradiation container (1) and a plurality of medium modules (2) arranged in the irradiation container, wherein the irradiation container and the medium modules are both rectangular parallelepiped structures; The length (a) and height (h) of a single medium module are slightly less than one-third of the length (a') and height (h') of the irradiation container, respectively, and the width (b) of a single medium module is slightly less than the width (b') of the irradiation container; The total number of the media modules = the number of fully loaded media modules in the irradiation container * the number of irradiation stations, where the irradiation stations are used to place the irradiation containers.

6. The dose field testing and analysis method for a gamma irradiation medium module according to claim 5, characterized in that: The length, width and height of a single medium module are 390 mm, 585 mm and 460 mm respectively, and the length, width and height of the irradiation container are 1200 mm, 600 mm and 1400 mm respectively.

7. The dose field testing and analysis method for a gamma irradiation medium module according to claim 5, characterized in that: The medium module includes a module inner core and a module outer box. The module inner core is a low-density inner core, a medium-density inner core or a high-density inner core. The material of the module inner core is wooden honeycomb cardboard, corrugated cardboard + medium-density board or corrugated cardboard + high-density board. The module outer box is a wooden corrugated cardboard box.

8. The dose field testing and analysis method for a gamma irradiation medium module according to claim 7, characterized in that: The medium module is a homogeneous medium module, and the density of the medium module is in the range of 0.02-0.35 g / cm 3 , the density tolerance of the medium module is ±1.5%.

9. The dose field testing and analysis method for a gamma irradiation medium module according to claim 8, characterized in that: The density of the dielectric module is 0.02 g / cm 3 , 0.20g / cm 3 and 0.35g / cm 3 At least one of .

10. The dose field testing and analysis method for a gamma irradiation medium module according to claim 9, characterized in that: When the inner core of the medium module adopts a low-density inner core and the material of the inner core of the module adopts a wood honeycomb paperboard, the density of the medium module is 0.02g / cm 3 When the core of the medium module adopts a medium density core and the material of the core of the module adopts corrugated cardboard + medium density board, the density of the medium module is 0.20g / cm 3 When the core of the medium module adopts a high-density core and the material of the core of the module adopts corrugated cardboard + high-density board, the density of the medium module is 0.35g / cm 3 .

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