Static electron stepped irradiation table for improving fluence rate uniformity and preparation method and irradiation test method thereof

Abstract

The invention relates to an irradiation method and an irradiation device, in particular to a static electron stepped irradiation table capable of improving fluence rate uniformity, a preparation method of the static electron stepped irradiation table and an irradiation test method, and solves the technical problems of large errors and inconsistency of test results caused by non-uniform fluence rate of an existing electron irradiation test. The static electron stepped irradiation table comprises a central irradiation table and at least two edge irradiation tables, the central irradiation table and the edge irradiation table are both located in an electron beam irradiation area of the electron accelerator, and the upper surfaces of the central irradiation table and the edge irradiation table are both used for placing test samples to be irradiated; the at least two edge irradiation tables are symmetrically connected to the two sides of the center irradiation table in the length direction. The preparation method is simple and practical, and the stepped irradiation table prepared by the method can effectively improve the problem of non-uniform fluence rate distribution in the traditional method. According to the irradiation test method, the fluence rate uniformity in the irradiation area is improved from 12% to 5%.

Description

Technical Field

[0001] The invention relates to an irradiation method and an irradiation device, and in particular to a static electron step irradiation table for improving the uniformity of the injection rate, a preparation method thereof, and an irradiation test method. Background Art

[0002] Electron irradiation tests are widely used in materials, electronic components, and product testing in radiation environments. When conducting electron irradiation tests, the uniformity of the injection rate is a key factor affecting the accuracy of the test results.

[0003] like Figure 1 As shown in the figure, the existing electron irradiation test usually has the problem of uneven fluence rate, especially in the irradiation process of different areas and at different times, the fluence rate fluctuates greatly, which easily leads to large errors and inconsistency in the test results. Therefore, how to reduce the fluctuation of the fluence rate during electron irradiation and ensure the uniform distribution of the fluence rate in the irradiation area has become a difficult problem to be solved in electron irradiation test technology. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problem that the existing electron irradiation test has uneven injection rate, which leads to large errors and inconsistencies in the test results, and to provide a static electron step irradiation table and its preparation method and irradiation test method for improving the uniformity of the injection rate.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A static electron step irradiation table for improving the uniformity of the injection rate, which is special in that it comprises a central irradiation table and at least two edge irradiation tables;

[0007] The central irradiation table and the edge irradiation table are both located in the electron beam irradiation area of ​​the electron accelerator, and the center line of the central irradiation table along the length direction coincides with the center line of the electron beam irradiation area, and the upper surfaces of the central irradiation table and the edge irradiation table are used to place the test samples to be irradiated;

[0008] At least two edge irradiation stations are symmetrically connected to two sides of the central irradiation station along the length direction;

[0009] The height of the edge irradiation table is greater than that of the central irradiation table, so that the fluence rates of the central irradiation table and the edge irradiation table in the electron beam irradiation area of ​​the electron accelerator are equal.

[0010] Furthermore, a boundary irradiation station is provided on the side wall of the edge irradiation station away from the central irradiation station;

[0011] The height of the boundary irradiation table is greater than the height of the edge irradiation table.

[0012] At the same time, the present invention provides a method for preparing the above-mentioned static electron step irradiation table for improving the uniformity of the injection rate, which is special in that it includes the following steps:

[0013] 1] Determine the irradiation area based on the electron beam of the electron accelerator;

[0014] 2] Select multiple calibration points in the irradiation area;

[0015] 3] Use the Faraday cup to collect the electron charge at each calibration point, then connect the Faraday cup to the beam integrator, use the beam integrator to read the electron charge value, and then convert the electron charge value into the number of electrons;

[0016] 4] Calculate the fluence rate at each calibration point based on the number of electrons, the window area of ​​the Faraday cup, and the integral current time of the beam integrator;

[0017] 5] Divide the edge area and the center area according to the injection rate, and determine the positions of the edge irradiation station and the center irradiation station:

[0018] Determine whether the injection rate is greater than 0.98×10 11 e / cm 2 ·s, if yes, the irradiated area is divided into the central area; otherwise, the irradiated area is divided into the edge area;

[0019] 6] Adjust the height of the Faraday cage in the edge area along the axial direction, and calculate the fluence rate in the edge area according to the method of step 3] and step 4] until the fluence rate in the edge area is equal to the fluence rate in the center area; record the cumulative adjustment height of the Faraday cage in the edge area, which is the height difference between the edge irradiation table and the center irradiation table;

[0020] 7] According to the position and height difference of the edge irradiation table and the center irradiation table, a static electron step irradiation table with improved injection rate uniformity is obtained.

[0021] Further, step 2] is specifically as follows:

[0022] Select more than or equal to 3 calibration points on the center line of the irradiation area along the length direction, and select more than or equal to 3 calibration points on both sides of the center line.

[0023] Further, step 3] is specifically as follows:

[0024] 3.1. Place the Faraday cup at each calibration point, and then evacuate the Faraday cup. When the vacuum degree in the Faraday cup reaches 10 -2 When Pa, the Faraday cup and beam integrator are connected through a three-coaxial shielded cable, and the Faraday cup shell is grounded;

[0025] 3.2. Turn on the electron accelerator and set the displayed current of the beam integrator. When the displayed current reaches the set value, open the beam gate of the electron accelerator to start irradiation.

[0026] 3.3. Set the integration current time of the beam integrator, observe the beam integrator and read the value of the charge received during the integration time, and then convert the electron charge value into the number of electrons.

[0027] Further, step 4] is specifically as follows:

[0028] According to the number of electrons, the window area S of the Faraday cup beam of the Faraday cup, and the integral current time of the beam integrator, the fluence rate Je of each calibration point is calculated:

[0029]

[0030] Where I is the current displayed by the beam integrator, in A; e is the basic charge of the electron, which is 1.602×10 19 / C; t is the integral current time of the beam integrator, in seconds; S is the window area of ​​the Faraday cage beam, in cm 2 ; The unit of injection rate Je is e / cm 2 / s.

[0031] Furthermore, in step 5], the difference in fluence rate between the edge area and the central area is 10%.

[0032] Further, in step 1], the irradiation area is 70 cm×20 cm;

[0033] In step 2], 5 calibration points are selected on the center line of the irradiated area along the length direction, and 5 calibration points are selected on both sides of the center line.

[0034] Furthermore, in step 6], the height of the Faraday cage in the edge area is adjusted axially as follows:

[0035] The height of the Faraday cage in the edge region was adjusted in axial direction in steps of 1 cm.

[0036] In addition, the present invention also provides a static electron irradiation test method for improving the uniformity of the injection rate, which is special in that it includes the following steps:

[0037] Step 1, placing the test sample to be irradiated on a static electron step irradiation table for improving the uniformity of the fluence rate as described in claim 1 or 2;

[0038] Step 2: Turn on the electron accelerator, wait until the displayed current reaches the set value, open the beam gate of the electron accelerator, and conduct a static electron irradiation test to improve the uniformity of the injection rate.

[0039] Beneficial effects of the present invention:

[0040] 1. The present invention provides a static electron step irradiation table for improving the uniformity of the injection rate. The test sample to be irradiated is placed on the table, so that the irradiation process is more stable and reliable.

[0041] 2. The present invention provides a method for preparing a static electron step irradiation table for improving the uniformity of the injection rate. The method is simple and practical. The step irradiation table prepared by the method can effectively improve the problem of uneven injection rate distribution existing in the traditional method.

[0042] 3. The static electron irradiation test method for improving the uniformity of the injection rate of the present invention reduces the difference in the uniformity of the injection rate in the irradiated area. It can improve the uniformity of the injection rate by mastering the electron beam irradiation law without changing the original electron accelerator equipment, thereby reducing the cost investment and having good economic benefits and high applicability.

[0043] 4. The static electron irradiation test method for improving the uniformity of the injection rate of the present invention can improve the consistency of the irradiation flux of the test sample to be irradiated in the original irradiation area, and increase the uniformity of the injection rate in the irradiation area from 12% to 5%.

[0044] 5. The static electron irradiation test method of the present invention for improving the uniformity of the injection rate can ensure that the dose distribution during the irradiation process is more uniform, thereby improving the accuracy of the test to within 5%. This method is not only suitable for various tests of static electron irradiation, but also has a good prospect for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of the locations of the existing electron accelerator and the test samples to be irradiated;

[0046] Figure 2 is a three-dimensional diagram of an electron accelerator and a stepped irradiation platform in an embodiment of the present invention;

[0047] Figure 3 A side view of an electron accelerator and a stepped irradiation platform in an embodiment of the present invention.

[0048] Description of reference numerals:

[0049] 1-electron accelerator, 2-test sample to be irradiated, 3-step irradiation station, 31-center irradiation station, 32-edge irradiation station, 33-boundary irradiation station. DETAILED DESCRIPTION

[0050] like Figure 2 , Figure 3As shown, the present invention provides a static electron step irradiation table for improving the uniformity of the injection rate, including a central irradiation table 31 and two edge irradiation tables 32; the central irradiation table 31 and the edge irradiation table 32 are both located in the electron beam irradiation area of ​​the electron accelerator 1, and the center line of the central irradiation table 31 along the length direction coincides with the center line of the electron beam irradiation area, and the upper surfaces of the central irradiation table 31 and the edge irradiation table 32 are used to place the test sample 2 to be irradiated.

[0051] Preferably, two edge irradiation tables 32 are symmetrically connected on both sides of the central irradiation table 31 along the length direction; the height of the edge irradiation table 32 is greater than the height of the central irradiation table 31, so that the central irradiation table 31 and the edge irradiation table 32 have the same fluence rate in the electron beam irradiation area of ​​the electron accelerator 1, and the manufacturing is convenient. A boundary irradiation table 33 is arranged on the side wall of the edge irradiation table 32 away from the central irradiation table 31. The height of the boundary irradiation table 33 is the sum of the height of the central irradiation table 31 and the cumulative adjustment height of the Faraday cage along the axial direction.

[0052] When the irradiated test sample 2 is subjected to static irradiation, the fluence rate of the electron accelerator 1 is measured by the Faraday cup and it is found that it is normally distributed in the specified irradiation area. The fluence rate is the highest directly below the titanium window of the Faraday cup and gradually decreases on both sides. During static irradiation, the fluence rate uniformity in the irradiation area is poor and cannot meet the requirements of uniform irradiation. The height of the irradiation area on both sides of the center line of the irradiation area is designed to increase the fluence rate at the edge position. Specifically, during the test, the spatial position distribution of the stepped irradiation table 3 is statically adjusted so that the height is higher on the outside, and the fluence rate on the outside is also increased accordingly. The height that meets the uniformity requirements is obtained by measurement. The irradiated test sample 2 is placed on the stepped irradiation table 3 to ensure that each point is irradiated with the electron beam as evenly as possible.

[0053] The method of the present invention reduces the difference in fluence rate uniformity in the irradiation area, can improve the fluence rate uniformity by mastering the electron beam irradiation law without changing the original electron accelerator 1 equipment, reduce cost investment, and has good economic benefits and high applicability.

[0054] At the same time, the present invention provides a method for preparing a static electron step irradiation table for improving the uniformity of the injection rate, comprising the following steps:

[0055] 1] Determine the irradiation area according to the electron beam of the electron accelerator 1; wherein the irradiation area is 70 cm×20 cm;

[0056] 2] Select 5 calibration points on the center line of the irradiation area, and select 5 calibration points on both sides of the center line;

[0057] 3] Use the Faraday cup to collect the electron charge at each calibration point, then connect the Faraday cup to the beam integrator, use the beam integrator to read the electron charge value, and then convert the electron charge value into the number of electrons;

[0058] 3.1. Place the Faraday cup at each calibration point, and then evacuate the Faraday cup. When the vacuum degree in the Faraday cup reaches 10 -2 When the measurement requirement is reached, the Faraday cup and beam integrator are connected through a three-coaxial shielded cable, and the Faraday cup housing is grounded to complete the preparation work;

[0059] 3.2. Turn on the electron accelerator 1 and set the displayed current of the beam integrator; when the displayed current reaches the set value, open the beam gate of the electron accelerator 1 to start irradiation;

[0060] 3.3. Set the integration time of the beam integrator to 10s, observe the beam integrator and read the value of the charge received during the integration time, and then convert the electron charge value into the number of electrons;

[0061] 4] Calculate the fluence rate Je at each calibration point based on the number of electrons, the window area S of the Faraday cup, and the integral current time of the beam integrator:

[0062]

[0063] Where I is the current displayed by the beam integrator, in A; e is the basic charge of the electron, which is 1.602×10 19 / C; t is the integral current time of the beam integrator, in seconds; S is the window area of ​​the Faraday cage beam, in cm 2 ; The unit of injection rate Je is e / cm 2 / s;

[0064] 5] Divide the edge area and the center area according to the fluence rate, and determine the positions of the edge irradiation station 32 and the center irradiation station 31:

[0065] Determine whether the injection rate is greater than 0.98×10 11 e / cm 2 ·s, if yes, the irradiated area is divided into the central area; otherwise, the irradiated area is divided into the edge area;

[0066] Preferably, the difference in fluence rate between the edge region and the central region is 10%, so that the boundary of the edge region is not too large, and the fluence rate uniformity in the edge region is relatively good, and it can be regarded as a region with uniform fluence rate.

[0067] 6] Adjust the height of the Faraday cage in the edge area along the axial direction, and calculate the fluence rate in the edge area according to the method of step 3] and step 4] until the fluence rate in the edge area is equal to the fluence rate in the center area; record the cumulative adjustment height of the Faraday cage in the edge area, which is the height difference between the edge irradiation platform 32 and the center irradiation platform 31;

[0068] 7] According to the position and height difference between the edge irradiation table 32 and the center irradiation table 31, a static electron step irradiation table for improving the uniformity of the injection rate is obtained.

[0069] In addition, the present invention provides a static electron irradiation test method for improving the uniformity of the injection rate, comprising the following steps:

[0070] Step 1, placing the test sample 2 to be irradiated on a static electron step irradiation table 3 for improving the uniformity of the fluence rate as described in claim 1 or 2;

[0071] Step 2: Turn on the electron accelerator 1, and when the displayed current reaches the set value, open the beam shutter of the electron accelerator 1 to perform a static electron irradiation test to improve the uniformity of the injection rate.

[0072] According to the static electron irradiation test method for improving the uniformity of the fluence rate of the present invention, 15 calibration points are selected within the range of 70cm×20cm directly below the window of the Faraday tube beam, and the 15 calibration points are evenly distributed; and then the fluence rate of each calibration point is calibrated respectively. The fluence rate is selected to be greater than 0.98×10 11 e / cm 2 / s is the central irradiation area, and the injection rate is selected to be less than or equal to 0.98×10 11 e / cm 2 / s is the edge irradiation area; the boundary line between the edge irradiation area and the central irradiation area is basically a straight line, which determines the boundary of the edge irradiation area. Raise the height of the edge irradiation area, and initially determine to raise it by 1cm to facilitate the calculation of the height. Select at least 5 calibration points in the edge irradiation area, and calibrate the fluence of each calibration point. If the measured fluence rate of each calibration point is greater than 0.98×10 11 e / cm 2 / s, the requirement is met and 1cm is used as the height of the edge irradiation area. If the requirement is not met, continue to raise the height of the edge irradiation area and measure the fluence rate of at least 5 calibration points. Use this method to determine the height of the edge irradiation area.

Claims

1. A static electron step irradiation station for improving the uniformity of the fluence rate, characterized in that: It comprises a central irradiation station (31) and at least two edge irradiation stations (32); The central irradiation table (31) and the edge irradiation table (32) are both located in the electron beam irradiation area of ​​the electron accelerator (1), and the center line of the central irradiation table (31) along the length direction coincides with the center line of the electron beam irradiation area, and the upper surfaces of the central irradiation table (31) and the edge irradiation table (32) are both used to place the test sample (2) to be irradiated; At least two edge irradiation stations (32) are symmetrically connected to two sides of the central irradiation station (31) along the length direction; The height of the edge irradiation table (32) is greater than the height of the central irradiation table (31), so that the central irradiation table (31) and the edge irradiation table (32) have the same fluence rate in the electron beam irradiation area of ​​the electron accelerator (1).

2. A static electron step irradiation table for improving the uniformity of the fluence rate according to claim 1, characterized in that: A boundary irradiation platform (33) is arranged on the side wall of the edge irradiation platform (32) away from the central irradiation platform (31); The height of the boundary irradiation platform (33) is greater than the height of the edge irradiation platform (32).

3. A method for preparing a static electron step irradiation table for improving the uniformity of the fluence rate as claimed in claim 1, characterized in that: The following steps are involved: 1] Determining an irradiation area based on an electron beam from an electron accelerator (1); 2] Select multiple calibration points in the irradiation area; 3] Use the Faraday cup to collect the electron charge at each calibration point, then connect the Faraday cup to the beam integrator, use the beam integrator to read the electron charge value, and then convert the electron charge value into the number of electrons; 4] Calculate the fluence rate at each calibration point based on the number of electrons, the window area of ​​the Faraday cup, and the integral current time of the beam integrator; 5] Divide the edge area and the center area according to the fluence rate, and determine the positions of the edge irradiation station (32) and the center irradiation station (31): Determine whether the injection rate is greater than 0.98×10 11 e / cm 2 ·s, if yes, the irradiated area is divided into the central area; otherwise, the irradiated area is divided into the edge area; 6] Adjust the height of the Faraday cage in the edge area along the axial direction, and calculate the fluence rate of the edge area according to the method of step 3] and step 4] until the fluence rate of the edge area is equal to the fluence rate of the center area; record the cumulative adjustment height of the Faraday cage in the edge area, which is the height difference between the edge irradiation platform (32) and the center irradiation platform (31); 7] According to the position and height difference between the edge irradiation table (32) and the central irradiation table (31), a static electron step irradiation table for improving the uniformity of the injection rate is obtained.

4. The method for preparing a static electron step irradiation table for improving the uniformity of the fluence rate according to claim 3, characterized in that: Step 2] Specifically: Select more than or equal to 3 calibration points on the center line of the irradiation area along the length direction, and select more than or equal to 3 calibration points on both sides of the center line.

5. The method for preparing a static electron step irradiation table for improving the uniformity of the fluence rate according to claim 4, characterized in that: Step 3] Specifically: 3.

1. Place the Faraday cup at each calibration point, and then evacuate the Faraday cup. When the vacuum degree in the Faraday cup reaches 10 -2 When Pa, the Faraday cup and beam integrator are connected through a three-coaxial shielded cable, and the Faraday cup shell is grounded; 3.

2. Turn on the electron accelerator (1) and set the displayed current of the beam integrator; when the displayed current reaches the set value, open the beam shutter of the electron accelerator (1) to start irradiation; 3.

3. Set the integration current time of the beam integrator, observe the beam integrator and read the value of the charge received during the integration time, and then convert the electron charge value into the number of electrons.

6. The method for preparing a static electron step irradiation table for improving the uniformity of the fluence rate according to claim 5, characterized in that: Step 4] Specifically: According to the number of electrons, the window area S of the Faraday cup beam of the Faraday cup, and the integral current time of the beam integrator, the fluence rate Je of each calibration point is calculated: Where, I is the current displayed by the beam integrator, in A; e is the basic charge of an electron, which is 1.602×10 19 / C; t is the integral current time of the beam integrator, in seconds; S is the window area of ​​the Faraday cage beam, in cm 2 ; The unit of injection rate Je is e / cm 2 / s.

7. The method for preparing a static electron step irradiation table for improving the uniformity of the fluence rate according to claim 6, characterized in that: In step 5], the difference in the fluence rate between the edge area and the central area is 10%.

8. The method for preparing a static electron step irradiation table for improving the uniformity of the fluence rate according to claim 7, characterized in that: In step 1], the irradiation area is 70 cm×20 cm; In step 2], 5 calibration points are selected on the center line of the irradiated area along the length direction, and 5 calibration points are selected on both sides of the center line.

9. The method for preparing a static electron step irradiation table for improving the uniformity of the fluence rate according to claim 8, characterized in that: In step 6], the height of the Faraday cage in the edge area is adjusted axially as follows: The height of the Faraday cage in the edge region was adjusted in axial direction in steps of 1 cm.

10. A static electron irradiation test method for improving the uniformity of the injection rate, characterized in that: The following steps are involved: Step 1, placing the test sample (2) to be irradiated on a static electron step irradiation table (3) for improving the uniformity of the fluence rate as described in claim 1 or 2; Step 2: Turn on the electron accelerator (1), wait until the displayed current reaches the set value, open the beam shutter of the electron accelerator (1), and conduct a static electron irradiation test to improve the uniformity of the injection rate.

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