Neutron target with low thermal stress
By using a double-layer target design and a grooved structure to disperse stress, the problem of limited neutron yield caused by thermal stress in the neutron target was solved, resulting in higher neutron yield and higher proton beam intensity, and simplifying experimental verification.
Patent Information
- Application Number
- CN202511783755.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-03-10
AI Technical Summary
Neutron targets have limited neutron yield due to thermal stress issues. Current technologies reduce heat flux density by decreasing beam intensity, which leads to reduced neutron yield and prolonged treatment time.
The design employs a dual-layer target plate. The first target layer is divided into a central target plate and a fan-ring target plate by grooves. The material of the second target layer has greater ductility than that of the first target layer and extends from the first target layer to the second target layer through grooves. Combined with the design of the cooling component, it disperses stress and improves the ductility of the material.
It effectively reduces the stress distribution of the target sheet, avoids local stress concentration, increases neutron yield, can withstand higher proton beam intensity, improves neutron yield, and simplifies experimental verification.
Smart Images
Figure CN121645653A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of neutron targets, in particular to a neutron target with low thermal stress. BACKGROUND
[0002] In the BNCT industry, the target material for generating neutrons also needs to bear the heat generated by nuclear reactions, and the high heat flow generated by nuclear reactions may cause thermal stress concentration on the target, which may cause the target sheet to break when the stress limit is exceeded. In order to ensure the safe operation of the target, the general measures that can be taken are to reduce the beam current, reduce the proton beam current to the target, and thus reduce the heat flux density on the target, but this will cause the neutron yield to decrease, which will prolong the patient's treatment time. Therefore, how to ensure that the stress limit is not exceeded while ensuring the neutron yield is a technical problem that needs to be solved for the current neutron target. SUMMARY
[0003] The purpose of the present application is to solve the technical problem that the neutron yield is limited due to the problem of thermal stress in the prior art, and the following technical solution is provided:
[0004] A neutron target with low thermal stress, comprising a first target layer and a second target layer, the non-bombarding surface of the first target layer is welded with one side surface of the second target layer; the first target layer is divided into a center target sheet and a plurality of fan ring target sheets distributed around the center target sheet by a groove, the depth of the groove extends from the first target layer to the second target layer and the groove bottom is located on the second target layer, and the material ductility of the second target layer is greater than that of the first target layer.
[0005] In the above design scheme of the neutron target provided by the present application, the neutron target is designed as a double-layer target sheet, and the material ductility of the second target layer is greater than that of the first target layer, and in combination with the design of the groove, the first target layer is divided into a center target sheet and a plurality of fan ring target sheets, thereby dispersing the first target layer, increasing the unconstrained surface of the first target layer, and reducing the stress distribution on the first target layer; further, the groove of the present application extends from the first target layer to the second target layer and the depth is deep enough to span the first target layer and the second target layer, which can reduce the stress on the first target layer by dividing the first target layer and the first target layer and the second target layer, and at the same time, by setting the second target layer with higher ductility than the first target layer, the second target layer can not only reduce the discontinuity in the geometric structure and reduce the thermal stress concentration problem, but also prevent the first target layer from breaking and leaking cooling medium. In summary, the structural design of the neutron target can greatly reduce the stress distribution on the target sheet, avoid local stress concentration points, and thus reduce the overall stress of the target surface; at the same time, it can further withstand higher proton beam intensity, not only making up for the reduction of neutron yield caused by the groove, but also further improving the neutron yield.
[0006] Preferably, the first target layer has a thickness of (3-8) mm, and the second target layer has a thickness of (10-15) mm. In particular, the ratio of the thickness of the first target layer to the thickness of the second target layer in the above scheme is between (0.2-0.8), which is beneficial to balance
[0007] Further, the ratio of the width of the groove to the depth of the groove is between (0.03-0.06).
[0008] In the above scheme, the present application provides a ratio of the width of the groove to the depth of the groove, and within this ratio range, the groove is set, which can make the neutron yield of the neutron target almost the same as that of the neutron target without the groove under the same beam intensity; at the same time, the stress of the neutron target is much smaller than that of the neutron target without the groove, which offsets the decrease of the neutron yield caused by the groove; further, the groove set within this ratio parameter range can further improve the neutron yield by increasing the beam intensity. The ratio of the width of the groove to the depth of the groove provided by the present application is between (0.03-0.06), which greatly simplifies the verification of experimental data in the research and development process, and provides parameter technical support for the stress design of the neutron target.
[0009] Preferably, the width of the groove between any two adjacent fan ring target pieces is between (0.1-0.5) mm, and the width of the groove gradually decreases from the outer periphery of the neutron target to the center; the depth of the groove is 8.5 mm.
[0010] Preferably, the first target layer is beryllium, and the second target layer is copper. The ductility of copper is better than that of beryllium, which can compensate for the discontinuity of the geometric structure of the first target layer caused by the groove and reduce the problem of thermal stress concentration. The first target layer is beryllium, which serves as the main bombardment target to generate neutrons.
[0011] Preferably, the fan ring target piece is provided with 8 pieces.
[0012] The first target layer and the second target layer are both circularly arranged, and the diameters of the first target layer and the second target layer are both (100-200) mm.
[0013] The diameter of the center target piece is (10-20) mm. The diameter of the center target piece is selected to be between (10-20) mm, which is beneficial to balance the thermal stress distribution and the problem of thermal stress concentration.
[0014] The other side of the second target layer is provided with a first groove and a plurality of second grooves, the first groove corresponds to the center target piece, and the second grooves correspond to the fan ring target pieces one by one.
[0015] The second target layer is fixedly connected with the cooling assembly, and the first groove and the second grooves jointly form a cooling liquid flow channel with the cooling liquid output end of the cooling assembly.
[0016] In the above scheme, the present application also combines the characteristics of the high ductility of the copper material selected for the second target layer, and provides the second target layer with the first groove and the plurality of second grooves, which is conducive to the heat conduction between the first target layer and the second target layer, and because the second target layer forms the cooling liquid flow channel, it is also conducive to the heat dissipation of the second target layer, and further, it can also solve the discontinuity problem of the geometric structure of the first target layer. BRIEF DESCRIPTION OF DRAWINGS
[0017] Figure 1 is a schematic view of the structure of the neutron target;
[0018] Figure 2 is a schematic view of the top structure of the first target layer of the neutron target;
[0019] Figure 3 is a cross-sectional view of the neutron target at A-A;
[0020] Figure 4 is a cross-sectional view of the neutron target at B-B;
[0021] Figure 5 is a cross-sectional view of the neutron target at C-C;
[0022] In the figure: 1. first target layer, 11. center target piece, 12. fan ring target piece, 2. second target layer, 21. first groove, 22. second groove, 3. groove, 4. cooling assembly, 41. jet plate, 42. first sealing plate, 43. second sealing plate, 44. inflow hole, 45. outflow hole, 46. jet hole, 47. first chamber, 48. second chamber. DETAILED DESCRIPTION
[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all embodiments.
[0024] Therefore, the following detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but only represents some embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.
[0025] It should be noted that the embodiments in the present application and the features and technical solutions in the embodiments can be combined with each other without conflict.
[0026] It should be noted that similar reference numerals and letters refer to like items in the accompanying drawings, and once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings. In the description of the application, it should be explained that the terms "upper", "lower", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly placed when the product of the application is used, or the orientation or positional relationship commonly understood by those skilled in the art, and such terms are only for the convenience of describing the application and simplifying the description, and cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application. In addition, the terms "first", "second", and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.
[0027] Referring to Figures 1 to 5 The present application relates to a neutron target with low thermal stress, comprising a first target layer 1 and a second target layer 2, the non-bombarding surface of the first target layer 1 is welded with one side surface of the second target layer 2; the first target layer 1 is divided into a central target sheet 11 and a plurality of fan ring target sheets 12 distributed around the central target sheet 11 by a groove 3, the depth of the groove 3 extends from the first target layer 1 to the second target layer 2 and the groove bottom of the groove 3 is located on the second target layer 2, the material ductility of the second target layer 2 is greater than that of the first target layer 1.
[0028] The other side surface of the second target layer 2 is provided with a first groove 21 and a plurality of second grooves 22, the first groove 21 corresponds to the central target sheet 11, and the second grooves 22 correspond to the fan ring target sheets 12 one by one.
[0029] The second target layer 2 is fixedly connected with a cooling assembly 4, and the first grooves 21 and the second grooves 22 jointly form a cooling liquid flow channel with the cooling liquid output end of the cooling assembly 4.
[0030] The cooling assembly 4 comprises a jet plate 41, the jet plate 41 is provided with a first sealing plate 42 away from one side of the neutron target, the first sealing plate 42 is welded with the jet plate 41 and forms a first chamber 47; the other side of the jet plate 41 is provided with a second sealing plate 43, the second sealing plate 43 is welded with the second target layer 2, and the second target layer 2, the second sealing plate 43 and the jet plate 41 jointly form a second chamber 48. Specifically, a plurality of through holes are provided on the second sealing plate 43, the through holes correspond to the first grooves 21 and the second grooves 22 one by one, so that the second target layer 2, the second sealing plate 43 and the jet plate 41 jointly form the second chamber 48.
[0031] One or more inflow holes 44 are arranged on the first sealing plate 42, a plurality of jet holes 46 are arranged on the jet plate 41, and the jet holes 46 correspond to the first grooves 21 or the second grooves 22 one by one; one or more outflow holes 45 are arranged on the second sealing plate 43.
[0032] In the embodiment, two inflow holes 44 are arranged, and the inflow holes 44 are used to connect the output end of the cooling liquid circulation system.
[0033] In the embodiment, two outflow holes 45 are arranged, and the outflow holes 45 are used to connect the input end of the cooling liquid circulation system.
[0034] Further, the jet holes 46 are arranged protruding from the surface of the jet plate 41 to form jet channels, and the cooling liquid flow channel formed in the second chamber 48 forms a concave-convex flow channel, which is beneficial to increase the turbulence degree of the cooling liquid in the second chamber 48, and further improve the heat exchange efficiency between the second target layer 2 and the cooling liquid.
[0035] The working principle of the neutron target is as follows: the cooling liquid flows into the first chamber 47 formed by the jet plate 41 and the first sealing plate 42 through the inflow holes 44, and then the cooling liquid is jetted into the second chamber 48 formed by the second target layer 2, the second sealing plate 43 and the jet plate 41 through the jet holes 46, the cooling liquid contacts the second target layer 2 after entering the second chamber 48, and heat exchange is performed, the cooling liquid is heated, and the heat of the second target layer 2 is taken away, so as to cool the second target layer 2 and the first target layer 1 in contact with the second target layer 2, and the first target layer 1 is cooled; the cooling liquid flows out from the outflow holes 45 and enters the cooling liquid circulation system.
[0036] In the neutron target provided by the present application, the neutron target is designed as a double-layer target plate, the material of the second target layer 2 has greater ductility than the first target layer 1, and the first target layer 1 is divided into a central target plate 11 and a plurality of fan ring target plates 12 by the groove 3, so that the first target layer 1 is dispersed, the unconstrained surface of the first target layer 1 is increased, and the stress distribution on the first target layer 1 is reduced. Furthermore, the groove 3 extends from the first target layer 1 to the second target layer 2, and the deepest groove 3 does not cut the second target layer 2. This design can reduce the stress on the first target layer 1 by dividing the first target layer 1 and the first target layer 1 and the second target layer 2, and by setting the second target layer 2 with higher ductility than the first target layer 1, the second target layer 2 can not only reduce the discontinuity of the geometric structure and reduce the thermal stress concentration problem, but also prevent the first target layer 1 from breaking and leaking cooling medium. In summary, the structure design of the neutron target can greatly reduce the stress distribution on the target plate, avoid local stress concentration points, and further reduce the overall stress of the target surface. At the same time, it can further withstand higher proton beam intensity, not only compensating for the reduction of neutron yield caused by the groove 3, but also further improving the neutron yield.
[0037] Preferably, the thickness of the first target layer 1 is (3-8) mm, and the thickness of the second target layer 2 is (10-15) mm. Specifically, the thickness ratio of the first target layer 1 to the second target layer 2 in the above scheme is between (0.2-0.8), which is convenient for balancing
[0038] Further, the ratio of the width of the groove 3 to the depth of the groove 3 is between (0.03-0.06).
[0039] In the above scheme, the present application provides a ratio of the width of the groove 3 to the depth of the groove 3, which is set within this ratio range. Under the same beam intensity, the neutron yield of the neutron target can be almost the same as that of the neutron target without the groove 3. At the same time, the stress of the neutron target is much smaller than that of the neutron target without the groove 3, which offsets the reduction of the neutron yield caused by the groove 3. Furthermore, the groove 3 set within this ratio parameter range can further improve the neutron yield by increasing the beam intensity.
[0040] Preferably, the width of the groove 3 between any two adjacent fan ring target plates 12 is between (0.1-0.5) mm, and the width of the groove 3 gradually decreases from the outer periphery of the neutron target to the center. The depth of the groove 3 is 8.5 mm.
[0041] Preferably, the first target layer 1 is beryllium; the second target layer 2 is copper. The ductility of copper is better than that of beryllium, which can make up for the discontinuity of the geometric structure of the first target layer 1 caused by the groove 3, and reduce the problem of thermal stress concentration.
[0042] Preferably, the fan ring target piece 12 is provided with 8.
[0043] The first target layer 1 and the second target layer 2 are both circularly arranged, and the diameters of the first target layer 1 and the second target layer 2 are both (100-200) mm.
[0044] The diameter of the central target piece 11 is (10-20) mm. The diameter of the central target piece 11 is selected to be between (10-20) mm, so as to balance the problem of thermal stress distribution and thermal stress concentration.
[0045] Embodiment 1:
[0046] In embodiment 1, the neutron target structure provided by the present application is used, and the specific parameters are as follows: the first target layer 1 is beryllium, the second target layer 2 is copper, the thickness of the first target layer 1 is 5 mm, the thickness of the second target layer 2 is 12 mm, the diameters of the first target layer 1 and the second target layer 2 are both 150 mm, the fan ring target piece 12 is provided with 8, the diameter of the central target piece 11 is 15 mm, the width of the groove 3 around the central target piece 11 is 0.3 mm, the width of the groove 3 of any two adjacent fan ring target pieces 12 is between (0.1-0.5) mm, and the width of the groove 3 gradually decreases from the outer periphery of the neutron target to the center, so the average width of the groove 3 of any two adjacent fan ring target pieces 12 can be considered to be 0.3 mm; the depth of the groove 3 is 2.5 mm, that is, the ratio of the width of the groove 3 to the depth of the groove 3 is 0.12. In this embodiment 1, the power of the beam to the first target layer 1 is set to 32 KW, the cooling liquid is water, and the flow rate of the cooling liquid is 15 m 3 / h.
[0047] Based on the specific parameters of the structure of the neutron target provided in embodiment 1, the present application simulates the following data results by using ANSYS software.
[0048] 1. In the case of maintaining the beam intensity at 1 mA, the stress results and neutron yield of the neutron target are simulated as follows, and the specific results are shown in Table 1.
[0049] 2. In the case of maintaining the neutron yield at 1, the stress results of the neutron target are simulated by adjusting the beam intensity, and the specific results are shown in Table 2.
[0050] 3. In the case of not exceeding the stress limit (450-500) MPa, the neutron yield value is increased by increasing the proton beam intensity within a certain range, and the specific results are shown in Table 3.
[0051] Example 2
[0052] The same neutron target as in Example 1 is used, except that in Example 2, the depth of the groove is 5 mm, i.e. the ratio of the width of the groove to the depth of the groove is 0.06.
[0053] Based on the specific parameters of the structure of the neutron target provided in Example 2, the present application simulates the following data results by using ANSYS software:
[0054] 1. In the case of maintaining the beam intensity at 1 mA, the stress results and neutron yield of the neutron target are simulated as follows, and the specific results are shown in Table 1.
[0055] 2. In the case of maintaining the neutron yield at 1, the stress results of the neutron target are simulated by adjusting the beam intensity, and the specific results are shown in Table 2.
[0056] 3. In the case of not exceeding the stress limit (450-500) MPa, the neutron yield value is increased by increasing the proton beam intensity within a certain range, and the specific results are shown in Table 3.
[0057] Example 3
[0058] The same neutron target as in Example 1 is used, except that in Example 3, the depth of the groove is 5.5 mm, i.e. the ratio of the width of the groove to the depth of the groove is 0.05.
[0059] Based on the specific parameters of the structure of the neutron target provided in Example 3, the present application simulates the following data results by using ANSYS software:
[0060] 1. In the case of maintaining the beam intensity at 1 mA, the stress results and neutron yield of the neutron target are simulated as follows, and the specific results are shown in Table 1.
[0061] 2. In the case of maintaining the neutron yield at 1, the stress results of the neutron target are simulated by adjusting the beam intensity, and the specific results are shown in Table 2.
[0062] 3. In the case of not exceeding the stress limit (450-500) MPa, the neutron yield value is increased by increasing the proton beam intensity within a certain range, and the specific results are shown in Table 3.
[0063] Example 4
[0064] The same neutron target as in Example 1 is used, except that in Example 4, the depth of the groove is 6.5 mm, the width of the groove is 0.2 mm, i.e. the ratio of the width of the groove to the depth of the groove is 0.031.
[0065] Based on the specific parameters of the structure of the neutron target provided in Example 4, the present application simulates the following data results by ANSYS software:
[0066] 1. In the case of maintaining the beam intensity at 1 mA, the stress results and neutron yield of the neutron target are simulated as follows, and the specific results are shown in Table 1.
[0067] 2. In the case of maintaining the neutron yield at 1, the stress results of the neutron target are simulated by adjusting the beam intensity, and the specific results are shown in Table 2.
[0068] 3. In the case of not exceeding the stress limit (450-500) MPa, the neutron yield value is increased by increasing the proton beam intensity within a certain range, and the specific results are shown in Table 3.
[0069] Example 5:
[0070] The same neutron target as in Example 1 is used, except that in Example 5, the depth of the groove is 7.5 mm, and the width of the groove is 0.4 mm, i.e. the ratio of the width of the groove to the depth of the groove is 0.053.
[0071] Based on the specific parameters of the structure of the neutron target provided in Example 5, the present application simulates the following data results by ANSYS software:
[0072] 1. In the case of maintaining the beam intensity at 1 mA, the stress results and neutron yield of the neutron target are simulated as follows, and the specific results are shown in Table 1.
[0073] 2. In the case of maintaining the neutron yield at 1, the stress results of the neutron target are simulated by adjusting the beam intensity, and the specific results are shown in Table 2.
[0074] 3. In the case of not exceeding the stress limit (450-500) MPa, the neutron yield value is increased by increasing the proton beam intensity within a certain range, and the specific results are shown in Table 3.
[0075] Example 6:
[0076] The same neutron target as in Example 1 is used, except that in Example 6, the depth of the groove is 8.5 mm, i.e. the ratio of the width of the groove to the depth of the groove is between 0.035.
[0077] Based on the specific parameters of the structure of the neutron target provided in Example 6, the present application simulates the following data results by ANSYS software:
[0078] 1. In the case of maintaining the beam intensity at 1 mA, the stress results and neutron yield of the neutron target are simulated as follows, and the specific results are shown in Table 1.
[0079] 2. In the case of maintaining the neutron yield of 1, the stress results of the neutron target are simulated by adjusting the beam intensity, and the specific results are shown in Table 2.
[0080] 3. In the case of maintaining the stress limit of (450-500) MPa, the neutron yield value is improved by increasing the proton beam intensity in a certain range, and the specific results are shown in Table 3.
[0081] Example 7:
[0082] The same neutron target as in Example 1 is used, except that in Example 7, the depth of the groove is 9.5 mm, that is, the ratio of the width of the groove to the depth of the groove is between 0.032.
[0083] Based on the specific parameters of the structure of the neutron target provided in Example 7, the present application simulates the following data results by using ANSYS software:
[0084] 1. In the case of maintaining the beam intensity of 1 mA, the stress results and neutron yield of the neutron target are simulated as follows, and the specific results are shown in Table 1.
[0085] 2. In the case of maintaining the neutron yield of 1, the stress results of the neutron target are simulated by adjusting the beam intensity, and the specific results are shown in Table 2.
[0086] 3. In the case of maintaining the stress limit of (450-500) MPa, the neutron yield value is improved by increasing the proton beam intensity in a certain range, and the specific results are shown in Table 3.
[0087] Comparative Example 1:
[0088] The same neutron target as in Example 1 is used, except that in the comparative example, the depth of the groove is 0 mm, that is, the first target layer is a complete circular target piece divided by the groove.
[0089] Based on the specific parameters of the structure of the neutron target provided in the comparative example, the present application simulates the following data results by using ANSYS software:
[0090] 1. In the case of maintaining the beam intensity of 1 mA, the stress results and neutron yield of the neutron target are simulated as follows, and the specific results are shown in Table 1.
[0091] 2. In the case of maintaining the neutron yield of 1, the stress results of the neutron target are simulated by adjusting the beam intensity, and the specific results are shown in Table 2.
[0092] 3. The neutron yield value is improved by increasing the range of proton beam intensity while keeping the stress limit (450-500) MPa, and the specific results are shown in Table 3.
[0093] Comparative Example 2:
[0094] The same neutron target as in Example 1 is used, except that in Comparative Example 2, the depth of the groove is 5.5 mm, and the width of the groove is 0.4 mm, i.e., the ratio of the width of the groove to the depth of the groove (3) is between 0.072.
[0095] Comparative Example 3:
[0096] The same neutron target as in Example 1 is used, except that in Comparative Example 3, the depth of the groove is 9.5 mm, and the width of the groove is 0.6 mm, i.e., the ratio of the width of the groove to the depth of the groove is between 0.063.
[0097] In Examples 1-7 and Comparative Examples, the depth of the groove 3 is valued to 9.5 mm, considering the overall thickness of the overall first target layer 1 and the second target layer 2. If the depth of the groove 3 continues to deepen, it is not conducive to the design of the groove of the second target layer 2. At the same time, compared with the 8.5 mm depth of the groove 3, the performance of the neutron yield and the stress value is decreased compared with the 8.5 mm depth of the groove 3. According to the current processing technology level of the neutron target, the width of the groove 3 is best at (0.1-0.5) mm, and it is difficult to achieve the width less than 0.1 mm by using the current processing technology.
[0098] 1. In Examples 1-6 and Comparative Examples 1-3, the stress results and neutron yield data of the neutron target are simulated under the condition that the beam intensity is kept at 1 mA, and the results are shown in Table 1:
[0099]
[0100] In the above specific simulation parameters, when the ratio of the width of the groove 3 to the depth of the groove 3 is between 0.03-0.06 under the same beam intensity, the relative error of the neutron yield is relatively small, which is maintained within 6%, and the simulation results of the stress show that there is a very large difference in the size of the stress. At the same time, it can be seen from Comparative Examples 1, 2 and 3 that when the depth of the groove 3 extends to the second target layer 2, the stress is greatly reduced under the same condition, and the reduction amplitude of the stress is close to 1 times compared with the neutron target without the groove 3, which provides strong support for increasing the proton beam intensity in the future; although the stress of the segmented neutron target is reduced, it does not reach the technical effect of a large reduction.
[0101] 2. The stress results of the neutron target of Examples 1-7 and Comparative Examples 1-3 are summarized in Table 2 below by adjusting the beam intensity while keeping the neutron yield 1 constant:
[0102]
[0103]
[0104] In the above specific simulation parameters, the neutron yield needs to be kept constant by increasing the beam intensity under the same neutron yield. In Examples 3-7, only a slight increase in the proton beam intensity is required to meet the conditions, and the stress value is only slightly increased, which provides space for subsequent increase in the beam intensity and improvement in the neutron yield. However, in Comparative Examples 2 and 3, the proton beam intensity needs to be greatly increased under the condition that the stress value is increased to reach the established neutron yield. By comparing the stress test results of the first group of data and the second group of data, although the intensity of the beam in Examples 1-7 is increased, the stress simulation results show that the stress of the first target layer 1 is still much lower than that of Comparative Example 1.
[0105] 3. The data of Examples 1-7 and Comparative Examples 1-3 are as follows in Table 3 by increasing the proton beam intensity within a certain range while keeping the stress below the stress limit:
[0106]
[0107] By comparing the third group of data and the first group of data, by increasing the proton beam intensity, the neutron yield of Examples 3-7 is improved by (5-15) % compared with the data of Comparative Examples 1-3 and the second group of examples, and the stress is still much lower than that of the comparative examples, and the stress is reduced by more than 40%. The thickness of the first target layer 1 is 5 mm, which shows that when the depth of the groove 3 completely divides the first target layer 1 and partially divides the second target layer 2 without cutting off, the performance of the neutron target structure provided by the present application is better.
[0108] In summary, when the ratio of the width of the groove 3 to the depth of the groove 3 is between (0.03-0.06), the neutron yield of the neutron target not only basically approaches the neutron target without the groove 3, but also under the same conditions, the stress value is greatly reduced, which facilitates subsequent increase in the proton beam intensity and improvement in the neutron yield. At the same time, the depth of the groove 3 is best when it spans the first target layer 1 and the second target layer 2.
[0109] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art, according to the technical solution and inventive concept of the present application, makes equivalent replacement or change within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.
Claims
1. A neutron target having low thermal stress, characterized in that The target comprises a first target layer (1) and a second target layer (2), the non-bombarding surface of the first target layer (1) is welded with one side surface of the second target layer (2); the first target layer (1) is divided into a center target piece (11) and a plurality of fan ring target pieces (12) distributed around the center target piece (11) by a groove (3), the depth of the groove (3) extends from the first target layer (1) to the second target layer (2) and the groove bottom of the groove (3) is located on the second target layer (2), the material ductility of the second target layer (2) is greater than that of the first target layer (1).
2. A low thermal stress neutron target as in claim 1, wherein, The thickness of the first target layer (1) is (3-8) mm, and the thickness of the second target layer (2) is (10-15) mm.
3. A low thermal stress neutron target as in claim 1, wherein, The width of the groove (3) and the depth of the groove (3) are between (0.03-0.06).
4. A low thermal stress neutron target as claimed in claim 3, characterized in that The width of the groove (3) between any two adjacent fan ring target pieces (12) is between (0.1-0.5) mm, and the width of the groove (3) gradually decreases from the outer periphery of the neutron target to the center; the depth of the groove is 8.5 mm.
5. A low thermal stress neutron target as in claim 1, wherein, The first target layer (1) is beryllium, and the second target layer (2) is copper.
6. A low thermal stress neutron target as claimed in claim 5, characterized in that The fan ring target piece (12) is provided with 8.
7. A low thermal stress neutron target as in claim 1 wherein, The first target layer (1) and the second target layer (2) are both circularly arranged, and the diameters of the first target layer (1) and the second target layer (2) are both (100-200) mm.
8. A low thermal stress neutron target as in claim 6 wherein, The diameter of the center target piece (11) is (10-20) mm.
9. A low thermal stress neutron target as in claim 1 wherein, The other side surface of the second target layer (2) is provided with a first groove (21) and a plurality of second grooves (22), the first groove (21) corresponds to the center target piece (11), and the second grooves (22) one-to-one correspond to the fan ring target pieces (12).
10. A low thermal stress neutron target as in claim 9, wherein, The second target layer (2) is fixedly connected with a cooling assembly (4), and the first groove (21) and the second grooves (22) and the cooling liquid output end of the cooling assembly (4) jointly form a cooling liquid flow channel.