A method for testing the interruption of an electron beam device for radiation processing

Abstract

A method for testing the interruption of an electron beam device for radiation processing, comprising the following steps: selecting a reference plane at a certain distance from the scanning window; respectively measuring the time intervals required for the reference plane in step one to reach the position directly below the scanning window at different beam speeds; placing a thin film dosimeter strip on the reference plane determined in step one, with the direction of the thin film dosimeter strip perpendicular to the electron beam scanning direction; setting the irradiation parameters of the electron accelerator device; respectively simulating various faults at different transmission speeds to cause the shutdown, restarting the electron accelerator device to continue irradiation; measuring the thin film dosimeter strip, analyzing the data and forming a conclusion. Compared with the prior art, the present invention simulates the situation of irradiation processing interruption, and confirms whether the irradiated product can be released after restarting the equipment by analyzing and judging whether the irradiation dose of the product meets the set requirements, so as to achieve precise control of the quality of the irradiated product.

Description

Technical Field

[0001] The present invention relates to the field of irradiation technology, and particularly relates to a method for testing processing interruption of an electron beam device for radiation processing. Background Art

[0002] Irradiation processing refers to controlling rays to change the physical properties and chemical composition of the irradiated substance and making it into a new substance that people need, or causing irreversible losses and damages to organisms (such as microorganisms) to achieve the desired goal.

[0003] However, during the irradiation processing, irradiation processing interruption often occurs. Irradiation processing interruption means that the electron accelerator device suddenly fails and stops during production due to various reasons. At this time, there are still products under the beam. Without moving the products under the beam, the electron accelerator device can be restarted. At this time, it is necessary to evaluate the quality risk brought by the processing interruption, that is, whether it can still be released after the processing interruption, so as to reduce the quality loss. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for testing processing interruption of an electron beam device for radiation processing in view of the above-mentioned deficiencies of the prior art.

[0005] To solve the above technical problem, the technical solution adopted by the present invention is:

[0006] A method for testing processing interruption of an electron beam device for radiation processing, comprising the following steps:

[0007] Step 1: Select a reference plane at a certain distance from the scanning window;

[0008] Step 2: Measure the time intervals required for the reference plane in Step 1 to reach the position directly below the scanning window at the maximum beam speed and the minimum beam speed respectively;

[0009] Step 3: Place a thin film dosimeter strip on the reference plane determined in Step 1, and the direction of the thin film dosimeter strip is perpendicular to the electron beam scanning direction;

[0010] Step 4: Set the irradiation parameters of the electron accelerator device;

[0011] Step 5: Simulate various faults to cause shutdown at different transmission speeds, restart the electron accelerator device and continue irradiation;

[0012] Step 6: Measure the thin film dosimeter strip, analyze the data and draw a conclusion.

[0013] Further, the selected reference plane in Step 1 is a plane at a distance of 20±2 cm from the scanning window or the upper end surface of the product with the maximum height.

[0014] Furthermore, in Step 2, calculate the time interval required for the reference plane to reach the position directly below the scanning window at the maximum beam speed and the minimum beam speed.

[0015] Furthermore, in Step 3, the length of the thin-film dosimeter strip ≥ 20 cm.

[0016] Furthermore, in Step 4, the irradiation parameters are set to the middle section of the target dose range.

[0017] Furthermore, the simulated shutdown in Step 5 includes abnormal shutdowns caused by accelerator failures, beam-down system failures, and software failures.

[0018] Furthermore, according to the time interval determined in Step 2, simulate normal startup to failure shutdown so that the middle section of the thin-film dosimeter strip is directly below the scanning window.

[0019] Furthermore, in Step 6, the data analysis is expressed as a percentage deviation, and the judgment method is as follows:

[0020] Positive deviation

[0021] Negative deviation

[0022] D max-测量 —The maximum dose in the thin-film dosimeter strip;

[0023] D min-测量 —The minimum dose in the thin-film dosimeter strip;

[0024] —The average value in the thin-film dosimeter strip;

[0025] When processing is interrupted in radiation processing, the absorbed dose in the product follows the above rule, that is, the value of the absorbed dose in the product is:

[0026] D max-实际 =(1 + a)D max-正常 Equation 3;

[0027] D min-实际 =(1 + b)D min-正常 Equation 4;

[0028] When D max-实际 ≤D max-acc and D min-实际 ≥D min-ste the product can be released, otherwise the product is not allowed to be released;

[0029] D max-实际 —The maximum absorbed dose of the product after processing interruption;

[0030] Dmin-实际 — The minimum absorbed dose of the product after processing interruption;

[0031] D max-正常 — The maximum absorbed dose in the products of normal processing;

[0032] D min-正常 — The minimum absorbed dose in the products of normal processing;

[0033] D max-acc — The maximum acceptable dose of the product;

[0034] D min-ste — The minimum sterilization dose of the product, i.e., the minimum acceptable dose of the product.

[0035] Compared with the prior art, by simulating the situation of irradiation processing interruption, the present invention determines whether the product can be released after restarting the equipment by analyzing and judging whether the irradiation dose of the product meets the set requirements, so as to achieve precise control of the quality of irradiated products. Specific embodiments

[0036] The technical solutions in the embodiments of the present invention will be described clearly and completely below.

[0037] Embodiment 1

[0038] When the device is irradiated and processed by a 10 MeV - 100 kW electron accelerator, the accelerator fails and causes an interruption. After simulating the accelerator failure interruption, when the speed v = 2 m / min, the dose deviation values are: a = +6.3%, b = -4.9%; when v = 8 m / min, the dose deviation values are: a = +8%, b = -5.4%.

[0039] An accelerator failure occurred during the processing of a customer's product T-200-Y-R-S, see Table 1 for analysis

[0040] Table 1 Interruption of accelerator failure during the processing of product T-200-Y-R-S

[0041]

[0042] Embodiment 2: An accelerator failure occurred during the processing of a customer's product 2D10N-R-S, see Table 2 for analysis

[0043] Table 2 Interruption of accelerator failure during the processing of product 2D10N-R-S

[0044]

[0045]

[0046] Embodiment 3:

[0047] When the device is used for irradiation processing by a 10 MeV - 100 kW electron accelerator, a beam-down system failure occurs. After simulating the beam-down device failure interruption, when the speed v = 2 m / min, the dose deviation values are: a = +6.7%, b = -4.5%; when v = 8 m / min, the dose deviation values are: a = +7.6%, b = -5.2%.

[0048] A beam-down system failure occurred in a customer's product SCO - BR - S, resulting in an interruption. See Table 3 for analysis:

[0049] Table 3 Analysis of data on interruption caused by beam-down system failure in product SCO - BR - S

[0050]

[0051] The present invention is not limited to the described embodiments. Those skilled in the art can still make some modifications or changes without departing from the spirit of the present invention, that is, within the scope of disclosure. Therefore, the scope of protection of the present invention is subject to the scope defined by the claims.

Claims

1. A method for testing the interruption of an electron beam device for radiation processing, characterized in that: It includes the following steps: Step 1: Select a reference plane at a certain distance from the scanning window; Step 2: Measure the time intervals required for the reference plane in Step 1 to reach the position directly below the scanning window at different beam speeds respectively; Step 3: Place a thin film dosimeter strip on the reference plane determined in Step 1, with the direction of the thin film dosimeter strip perpendicular to the electron beam scanning direction; Step 4: Set the irradiation parameters of the electron accelerator device; Step 5: Simulate various faults at different transmission speeds to cause the shutdown of the electron accelerator device, and then restart the electron accelerator device to continue irradiation; Step 6: Measure the thin film dosimeter strip, analyze the data and form a conclusion.

2. The method for testing the interruption of an electron beam device for radiation processing according to claim 1, characterized in that: The reference plane selected in Step 1 is a plane at a distance of 20 ± 2 cm from the scanning window or the upper end surface of the product with the maximum height.

3. A method for testing the interruption of an electron beam device for radiation processing according to claim 1, characterized in that: In Step 2, measure the time intervals required for the reference plane to reach the position directly below the scanning window at the maximum beam speed and the minimum beam speed.

4. A method for testing the interruption of an electron beam device for radiation processing according to claim 1, characterized in that: In Step 3, the length of the thin film dosimeter strip is ≥ 20 cm.

5. A method for testing the interruption of an electron beam device for radiation processing according to claim 1, characterized in that: In Step 4, the irradiation parameters are set to the middle section of the target dose range.

6. A method for testing the interruption of an electron beam device for radiation processing according to claim 1, characterized in that: The shutdown simulated in Step 5 includes abnormal shutdowns caused by accelerator faults, beam-down system faults, and software faults.

7. A method for testing the interruption of an electron beam device for radiation processing according to claim 1, characterized in that: According to the time intervals determined in Step 2, simulate the normal startup to fault shutdown so that the middle section of the thin film dosimeter strip is directly below the scanning window.

8. A method for testing the interruption of an electron beam device for radiation processing according to claim 1, characterized in that: In Step 6, the data analysis is expressed as a percentage deviation, and the judgment method is as follows: D max-测量 — The maximum value of the dose in the thin-film dosimeter strip; D min-测量 — The minimum value of the dose in the thin-film dosimeter strip; — Mean value in the thin-film dosimeter strip; When a processing interruption occurs in radiation processing, the absorbed dose in the product follows the above rule, that is, the value of the absorbed dose in the product is: D max-实际 =(1 + a)D max-正常 Equation 3; D min-实际 =(1 + b)D min-正常 Equation 4; When D max-实际 ≤ D max-acc and D min-实际 ≤ D min-ste the product can be released; otherwise, the product is not allowed to be released. D max-实际 — Maximum absorbed dose of the product after processing interruption; D min-实际 — Minimum absorbed dose of the product after processing interruption; D max-正常 — The maximum absorbed dose in the products processed under normal conditions; D min-正常 — The minimum absorbed dose in the products processed under normal conditions; D max-acc — Maximum acceptable dose of the product; D min-ste — The minimum sterilization dose of the product, i.e., the minimum acceptance dose of the product.

Images